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Planning for Marine Cage Fish Farming following Coastal Zone Management Program …

Planning for Marine Cage Fish Farming following Coastal Zone Management Program
- Technological Options
Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Aquaculture Planning and Management, In the University of Hull

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  • 1. THE UNIVERSITY OF HULL Planning for Marine Cage Fish Farming following Coastal Zone Management Program - Technological Options Being a Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Aquaculture Planning and Management, The University of Hull, UK By Subir Kumar Ghosh   ¡ ¢ £ ¡ ¤ ¥ ¡ ¦ § § ¨ § © © ©
  • 2. Contents Sl. No. Chapter Page No. SUMMARY 3 ACKNOWLEDGEMENT 4 1. INTRODUCTION 6 1.1 Background 6 1.2 Literature Review 9 2. METHODOLOGY 13 2.1 Objectives 13 2.2 Study Plan 13 2.2.1 Production Potentials 13 2.2.2 Assessment of Nutrient Load of Farming Systems 14 2.2.3 Comparative Economics of Farming Systems 14 2.2.4 Development Strategy 14 2.3 The Farming Systems 15 2.4 The Factors Influencing Nutrient Loading 17 2.5 Mechanical Waste Recovery 20 2.6 Biological Waste Recovery 21 2.7 Waste Quantification 22 3. RESULTS 23 3.1 Mass Balance Analysis 24 3.2 Production Potential Assessment 35 3.3 Economics 39 4. DISCUSSIONS 46 5. CONCLUSIONS 54 6. REFERENCES 56 7. FIGURES 59 2
  • 3. Summary The increasing demand for food fish has led to increasing demand on aquaculture resources in terms land, water and inputs like energy and fish meal etc. Since aquaculture resource like any other resource is finite hence proper utilization of the resource needs to be based on sound principles of planning taking into account 1. Sustainable use of resource within the limits of ‘the carrying capacity of the environment’ 2. Selection of technology in terms of its nutrient loading and waste mitigation capacity, 3. Common resource use and 4. Economic return. The present assessment of the ‘Area Capacity’ of the Norwegian marine area in terms of aquaculture production is set on projected yield of 300 tons for cage volume of 12000 m3. The benchmark under reference is regulating Norwegian fish farming for nearly a decade while the emission levels has undergone sea change on account of development of new technology. The present study indicates the possibility of harnessing 600 to 3000 tons per unit, given the same cage volume as specified under the coastal zone management program called ‘LENKA’ by adopting the recent technological innovations without altering the benchmark in terms of nutrient loadings. Thus the technological innovations would put the given marine cage farming site to better use. It also makes a comparative study of the economic parameters such as cost of production, rate of return and sensitivity of the technological systems to anticipated risks. Thus a case is made out for sensitizing the planning process to environmental enabling potentials of the technological innovations. The planning process so developed besides permitting higher productivity could be used as a feed back control for generation of newer technology. Newer benchmarks for production could perhaps be set on the basis of newer nutrient emission levels. Thus short term goal could be set based on System2, medium term goal could be based on System3 and slightly long term goal could be set based on the outcome of the commercial trials of System5 adopting integrated fish-mussel-seaweed production. This system seems to be holding great promises in terms of not merely enhancing holding capacity but fulfilling such sustainability dimensions as ‘zero emission’, ‘resource generation’ and ‘integrated production’ beside being cost effective. If operationalised, the technology would render salmon farming truly sustainable. 3
  • 4. ACKNOWLEDGEMENT At the onset I would like to mention that it was a difficult task to under take a study of this magnitude for the purpose of writing a dissertation towards fulfillment of the Postgraduate Degree program. Driven by my interest in this kind of work and the encouragement received from my supervisor I had ventured into this arena without realizing its implications. As may be evident it has taken little too long in completing the work. This is primarily due to the fact that this is one area where considerable research effort and consequent high volume of information generation has taken place in past two decades. Gathering this information besides being time consuming also proved to be somewhat expensive. Besides, the farming sites being located in the North Western part of UK, away from the city of Hull, did not permit frequent visit to the agencies involved in planning/implementation of this kind of projects and hence seeking answers to various doubts. Accessing industry related information also proved to be a difficult job. Within the framework of above constraints it was possible for me to deliver the results primarily because the University of Hull provided me the necessary extension of time to submit the dissertation and acceding to my repeated requests seeking extension of time. I am grateful to the University for providing me the most precious input in this project by allowing the extra margin of time. I am highly obliged to the University for this. I am sure that given the resource at my disposal, it would not have been possible for me to meet the required fund for undertaking my study tour to Scotland for the purpose of visiting the farming sites, the various institutions connected with planning, development, and R & D pertaining marine cage fish farming. The University made this possible by granting me the travel fund. This was a very kind gesture for which I am and shall remain indebted to the University for all times. I sincerely thank all those persons who made this possible. As already indicated, the work required considerable inputs by way of relevant information and literatures. Besides being expensive, it was time consuming and required lot of support from the HIFI as well as the University library in arranging them through the facilities extended by the British Library network. I thank the University Library for their excellent support. I am extremely thankful to my Department in general and to Mr. Stephen Ridgway and Dr. Kevin Crean in particular for extending liberal assistance using Departmental resource. I would also like to thank Dr. K. Haywood for his encouragements. The person to whom I owe the success of this project is my Supervisor Mr. Ridgway who has been a constant source of encouragement. I am grateful to my employer, The National Bank for Agriculture and Rural Development (NABARD), for granting me Bank’s scholarship for higher studies without which it would not have been possible for me to pursue higher studies in UK. I most humbly acknowledge the confidence imposed in me by the Bank and dedicate this dissertation to The National Bank for Agriculture and Rural Development, Mumbai. I have received considerable first hand information related to my area of study from the following organizations: 1. Marine Harvest McConnell Farms Office, Blar Mohr, Fort William 2. Highland Council Planning Dept., Inverness 3. Scottish Environmental Protection Agency, Fort William 4. Sea Fish Industry Authority, Ardtoe, Acharcle, Argyll 5. Institute of Aquaculture, Stirling University, Stirling 6. Stirling Aquaculture, University of Stirling 7. The Crown Estate, Edinburgh 8. The Scottish Natural Heritage, Edinburgh. I am thankful to all these institutions for 4
  • 5. providing me necessary information and helping me in carrying out my project. My special thanks goes to Ms. Judy O’Rourke of the Sea Fish Industry Authority, Ardtoe, without whose help my visit to Ardtoe would not have materialized. I take this opportunity to thank her for the excellent logistic and library support. I acknowledge the help received from Marine Harvest McConnell Farms Office, Blar Mohr, Fort William in showing me the farm and providing economics related information. I acknowledge with a deep sense of gratitude the help and guidance received by me from Dr. Arne Ervik, whose work on the concept of MOM system had provoked me to take up this work. I am grateful to him for giving me patient hearing and offering valuable suggestions. I am grateful to him for introducing me to the works of Prof. Hans Ackefors, on nutrient emission, which has been used by me extensively in this project. My thanks go to Prof. Ackefors for sending me his publication on environmental impact of different farming technologies. The suggestions given by Dr. Beveridge were very useful in restricting the nature of the project work given the limitations. I am highly thankful to Dr. John Bobstock of Stirling Aquaculture for giving me hearing and providing me industry related information. I am thankful to Mr. Øivind Hatteland, Export Sales Manager, AKVA for sending me a copy of the KPMG publication, which was very handy and informative. It would have not been possible for me to pursue my studies in UK had it not been for the sacrifices of my loving wife Soma, who took upon herself the reign of the household during the long period of my absence. I doubt whether I could have ever completed this dissertation (being away from my family) but for the support from my sister-in-law (Madhumita Ray) and my co- brother (Sunirmal Ray). I am highly indebted to both of them for their co-operation and help. 5
  • 6. Planning for Marine Cage Fish Farming following Coastal Zone Management Program – Technological Options (Being a Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Aquaculture Planning and Management) INTRODUCTION Background The increasing demand for food fish has led to increasing demand on aquaculture resources in terms land, water and inputs like energy and fish meal etc. Since aquaculture resource like any other resource is finite hence proper utilization of the resource needs to be based on sound principles of planning taking into account 1. Sustainable use of resource within the limits of ‘the carrying capacity of the environment’ 2. Selection of technology in terms of its nutrient loading and waste mitigation capacity, 3. Common resource use and 4. Economic return. Aquaculture and Global Food Fish Supply One of the most important challenge before mankind is to meet the food for the increasing billions especially, more so in the context of the present scenario of declining agricultural production. The world population has grown from two billion in 1950 to the present level close to six billion. It is expected that our population on this planet is going to be 8.5 billion by the year 2025 and 10 billion by the year 2050 and may stabilize around 12 billion (FAO, 1998). The growth rate of world agricultural production is slowing down. From an annual rate of about 3 percent in the 1960s, it dropped to about 1.6 percent during the decade 1986-1995 (mainly because of the drastic production decline in countries formerly comprising the USSR) and is expected to be in the order of 1.8 percent for the period 1990-2010. (FAO, 1998). A different situation is true for the fisheries sector, production increased at a compound rate of 3.4 percent per year in the period 1960-1990, and this growth rate has been maintained over the past decade. During the last 15 years, this growth has essentially been a result of the rapid increase in aquaculture output, which recorded an annual increase of 11.8 percent in the period 1984-1996 (FAO, 1998). The global fish production in 1996 had reached the level of 110 million metric tons (mt) of which the contribution of aquaculture production was 26.3 tm comprising of 15.6 mt from inland sector and 10.7 mt from marine sector respectively This is excluding the production of aquatic plants, which amounted to 7.7 million tons in 1996 (FAO, 1998). Globally, landings of marine fish are continuing to level off, the annual growth rate having fallen from 6 percent during 1950 –1983 to 1.5 percent during the following decade to 0.6 percent during the 1995-1996 biennium. This is also the general trend for most major inland fishing areas of the world which faces a 6
  • 7. constant threat from increase in the loss and degradation of land, forest resources, biodiversity and habitat as well as the growing scarcity and pollution of freshwater (FAO, 1998). Thus keeping in view the burgeoning population growth and the consequent rise in food fish demand, which is projected to increase from the present level of 84.5 mt to 114.8 mt in 2025, a demand supply gap of 28.5 mt needs to be addressed. The above gap can only be bridged by augmenting production in the aquaculture sector (Ackefors, 1997). Aquaculture provided 20 percent of global fisheries production (and 29 percent of food fish) in 1996. The potential of aquaculture to meet the challenges of food security and to generate employment and foreign exchange has been clearly demonstrated by the rapid expansion of this sector, which has grown at an APR1 of almost 10 since 1984 compared with 3 for livestock meat and 1.6 for capture fisheries production (FAO, 1998). Such rapid growth of aquaculture has generated a number of environmental and resource use conflicts suggesting that the present form of aquaculture development is not sustainable and that there is need for environmental planning based on the principles of sustainability. Sustainable Delopment Sustainability is the dynamics of growth in a finite world. On the road to development, mankind has crossed two important milestones, which has shaped its existence on this planet. The first was ‘The Agricultural Revolution’ of the Neolithic period and the second, ‘The Industrial Revolution’ of the past two centuries. Both the revolutions were associated with productivity to meet growing human needs and demands. In the process of development it has used the natural resources, both renewable and non-renewable to produce goods and services. The success of both the revolutions at the end has led to scarcities whether in terms of pressure on land and water or in terms of fuels and minerals, which can be attributed to finiteness of the resources on one hand and the increasing demand from a rapidly growing population on the other. To add to the misery, the process of development has generated a cost viz. ‘the pollutants’. It has been stated that in our efforts to meet growing human needs, we draw too heavily, too quickly, on an already overdrawn environmental resource account. They may show profit on the balance sheets of our generation, but our children will inherit the losses. Thus as per the Brundtland Report, “sustainable development is the development that meets the needs of the present without compromising the ability of the future generations to meet their own needs”(UNWCED 1987). It is now clear that the planet has a capacity to withstand the impacts of development i.e. it has a capacity to produce - ‘the Limit’ and a capacity to absorb and assimilate the fall outs of development - ‘the Carrying Capacity’. Thus any activity within the limits of ‘limit’ and ‘carrying capacity’ could be carried out on a long-term basis without threatening our existence and was termed ‘Sustainable’ - giving rise to the concept of ‘Sustainability’. The above issues apply to aquaculture sector as well wherein environmental planning is based on the concept of i. Capacity to produce and ii. Capacity to absorb and assimilate the wastes. The environmental economists refer to this as the capacity of natural systems to provide ‘natural capital’ (as ‘source’, ‘sink’ and ‘service’ provider). Thus the ability of natural systems to provide energy and materials, and to absorb the interference of pollution and waste, is the critical threshold within which the world economy can expand. 7
  • 8. The ecological perspective of sustainable development is based on the concept of ‘carrying capacity’ i.e. the maximum impact that a given ecosystem can sustain, which has been put forward in the following words (Meadows, 1992): “The maximum population that can be supported indefinitely in a given habitat without permanently impairing the productivity of the ecosystem(s) upon which that population is dependent. Thus in order to be sustainable, the level and rate of natural resource depletion and pollution emissions should be no greater or faster than the level and rate of regeneration or absorption of environment systems”. The FAO defined it as: ‘Sustainable development is the management and conservation of natural resource base and the orientation of technological and institutional changes in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. Such sustainable development (in the agriculture, forestry and fisheries sectors) conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable’ (FAO, 1996). Thus sustainable development related to aquaculture would mean conservation of natural resource; technological soundness in terms of waste generation and waste mitigation, economic viability and its social acceptance. While the conservation of natural resource and social issues related to common resource use have been addressed by the existing environmental planning process by many workers in the field, the issues pertaining technological soundness and economic viability have not been integrated into the planning process. Thus environmental issues have attracted the attention of many research workers in the field (e.g. Ackefors et al.1979; Gowen et al.1987; Rosenthal et al 1988; Ackefors et al. 1990; Gowen 1994). The discharge of nutrients and wastes from aquaculture has been regulated through legal measures in many countries (Ackefors and Olburs 1995). The need for carrying out aquaculture in environmentally sustainable, socially acceptable and in harmony with principles of common resource use, has led to the formulation of integrated coastal zone management plan by the coastal states as a follow up of 1992 United Nations Conference on Environment and Development, in Rio de Janeiro, Brazil. There is competition for sites and water resource in the coastal zone between aquaculture and other users viz. agriculture, shipping, tourism, salt manufacture, harbors, aqua park etc. (Chua, 1992). To address such environmental issues on a regional scale, the concept of ‘holding capacity’ was developed to denote maximum aquaculture production attainable in a water body without eliciting an unacceptably high degree of environmental change. Several models have been developed for determining the response of standing water to nutrient loading for lake management and the same have been modified for use in cage fish farming (Beveridge 1984; Weston et. al.1994). Mass balance models was developed by Vollenweider (1968), which was modified by Dillon and Riger (1974) and adapted for cage culture by Beveridge (1984). This mass-balance equation is based on movement of phosphorus compounds through a lake system. Such models have been useful in Scotland for environmental impact assessment and management of freshwater lakes for aquaculture. There were some attempts to quantify holding capacities for salmonid culture in marine and brackish waters based on nutrient loading (H6kanson and Wallin 1991) and oxygen consumption 8
  • 9. of solid wastes (Aure and Stigebrandt 1989). Both of these models had their limitations having been developed for specific environments and not applicable for predictive value elsewhere. In order to deal with the environmental issues owing to rapid growth of the salmon industry in Norway coast a national program called ‘Nation-wide Assessment of the Suitability of the Norwegian Coastal Zone and Rivers for Aquaculture’ (LENKA), was started in 1987 and was completed in 1990 (Ibrekk 1993). The planning was based on the assessment of the ‘holding capacity’ of the coastal waters and integration of aquaculture with other coastal activities through identification of suitable coastal habitat for cage farming of salmon and subjecting the same to the ‘holding capacity’ of the site taking into account overall nutrient loading from all existing as well as proposed activities in the area. The next step in the direction of coastal zone management has been the development of ‘Modelling-On growing fish farms-Monitoring’ (MOM), which is a management system used to adjust the local environmental impact of marine fish farms to the holding capacity of the sites. The concept is based on integrating the elements of environmental impact assessment, monitoring of impact and environmental quality standards into one system. Thus it may be evident that the present direction of research /development covering environmental sustainability of marine aquaculture has taken into account the ‘carrying capacity’ of the coastal area as well as the ‘holding capacity’, accounting for competitive use of coastal resource by common users while integrating them into one common management plan. Following this it may be possible to spell out a development plan for aquaculture in a given marine area based on the level of nutrient loading by the cage farming practice of salmon in vogue. However it may be possible to develop alternate production plans for the same marine area considering available technologies with different waste reduction and mitigation efficiency and their economics of operation. It has been indicated that reduction in feed wastage by 30% would increase the potential of aquaculture by 6-8 % and in areas of high level of aquaculture activity such as Hordaland, the effect would be even greater (Ibrekk 1993). The strategy for such planning could be 1. Maximizing fish production based on existing pattern of nutrient loading from a given area, 2. Maximizing production within overall ‘carrying capacity’ limit using least polluting technology, 3. Maximizing return from a given area by adopting least cost production system thereby improving profit margin or 4. a combination of one or more of the above interests. Thus it may be necessary to look into the waste mitigating efficiency of the farming technology and the economics of production of salmon using these while working out a coastal zone management plan. The present exercise is a step in this direction to study the impact of the above elements on decision making if introduced into the existing Norwegian planning based on LENKA. The present assessment of the ‘Area Capacity’ of the Norwegian marine area in terms of aquaculture production from marine cages fish farming is not technology sensitive. It is based on the nutrient loading from traditional cage farming system of salmon with a projected yield of 300 tons from using conventional feed with FCR of 1.5 and accordingly setting the ‘Area Capacity’ norm. Thus it may be possible to improve the production plan by incorporating suitable technological innovations. 9
  • 10. Brief Literature Review There is increasing dependence on aquaculture as a food source for meeting the increasing protein requirement of the burgeoning world population (FAO 1998, Ackefors 1997, Baird et al. 1996). Intensive cultivation of marine fish species has substantially increased in last two decades resulting in increased interaction between fish farming and the environment (Rosenthal et al.1987, 1988; Gowen et al. 1989; Hall et al.1990, Weston 1991, Iwama 1991, Phillips et al.1990,1993 and Weston et al.1994). Of the different types of coastal aquaculture, intensive production has the greatest potential to generate waste. It has been estimated for example that production of 100 tons of salmonids with a feed conversion ratio of 1.5, could result in annual loading of 1 ton of total phosphorus; 97 ton of total nitrogen and approximately 50 ton of organic matter (Ibrekk et al. 1993). The effects of marine fish farming on the surrounding marine areas have been discussed by many authors (Braaten et al.1983, Beveridge 1984, 1996, Holmer 1991 & 1992, Holmer et al. 1996 and Gowen et al.1987). The wastes from the coastal aquaculture operations has the potential to enrich aquatic eco-systems (Aure & Stigebrandt 1990 and Aure et al.,1988), particularly when farms are located in semi-enclosed bays, which have restricted exchange (GESAMP 1996). The major impact has been observed on the benthic macrofauna (Brown et al.1987; Ritz et al. 1990; Weston, 1990; Headerson et al.1995 and Pearson et al. 1983) as well as physical and chemical change in the sediments (Brown et al.1987; Coyne et al. 1994 and Gowen et al. 1988). The most important benthic impacts include azoic sediments (Brown et al.1987, Weston 1990 and Tsutsumi et al. 1991), anoxic sediments (Hall et al.1990, Holmer & Krisstensen1992, 1996, Hargrave et al. 1993 and Wu et al. 1994) out gassing of methane and hydrogen sulphide (Samuelsen et al. 1988, Wildish et al. 1990a). Thus considering the negative environmental impact of marine cage fish culture, a need was felt for proper site selection, assessment of the capacity of any given marine area to withstand environmental loading and its integration in the coastal planning based on common resource use and social acceptance. As a first step to address such environmental issues on a regional scale, the concept of ‘holding capacity’ was developed to denote maximum aquaculture production attainable in a water body without eliciting an unacceptably high degree of environmental change. Several models existed for determining the response of standing water to nutrient loading for lake management and the same were modified for use in cage fish farming (Beveridge 1984; Weston et al. 1994). Mass balance models was developed by Vollenweider (1968), which was modified by Dillon and Riger (1974) and adapted for cage culture by Beveridge (1984). This mass-balance equation is based on movement of phosphorus compounds through a lake system. Such models have been useful in Scotland for environmental impact assessment and management of freshwater lakes for aquaculture. There were some attempts to quantify holding capacities for salmonid culture in marine and brackish waters based on nutrient loading (H6kanson and Wallin 1991) and oxygen consumption of solid wastes (Aure and Stigebrandt 1989). Both of these models had their limitations having been developed for specific environments and not applicable for predictive value elsewhere. The application of Geographical Information System to site selection for coastal aquaculture has also been developed (Ross et al.1993). Issues related to resource planning and management of 10
  • 11. coastal aquaculture have been discussed at length (Baird et al.1996). In addition to environmental and biological issues, the social and economic issues have been integrated in coastal aquaculture planning (Chua et al.1989, 1992 & 1993; GESAMP 1991a; Barg 1992 and Pullin et al.1993). A number of methods have been proposed and used for identifying and evaluating environmental impacts. United Nations Economic and Social Commission for Asia and the Pacific short-listed eight methods (ESCAP, 1985b). Each method has its advantages and disadvantages, and the best known are the checklists, matrices and networks (Pillay 1996). The main drawback with the checklists are that they do not provide any guidance on the ways an environmental component may be affected by one or more development features (Pillay 1996). The matrices suffer from the drawback that they focus on direct impact between two items, and result in compartmentalizing the environment into separate items. The cumulative impacts through different pathways are not evaluated. The network method addresses this problem and traces the causes and effects of the relevant factors however, it does not evaluate the magnitude of the impacts and also does not propose alternative projects (Pillay 1996). The situation arising out of competitive use of the coastal zone by growing users has necessitated regulation of the activities through coastal zone management. As per GESAMP (1996), Coastal Zone Management needs to ensure that ecological change does not exceed pre-determined and acceptable levels, for which a management framework is adopted prior to development that would include the establishment of Environmental Quality Objectives (EQOs) and Standards (EQSs). The framework is also expected to offer scope for an Environment Impact Assessment (EIA) and a Monitoring Program. A coastal zone management programme called LENKA (Nationwide Assessment of the suitability of the Norwegian Coastal Zone and Rivers for Aquaculture) was started in 1987 and ended in 1990. The program developed an efficient and standardized tool for coastal zone planning. The program is based on a methodology for assessing the suitability of marine areas for aquaculture. The marine areas holding capacity is determined by a developed model which is based on (1) an assessment of the maximum acceptable organic loading of the marine areas and (2) an assessment of the area available for aquaculture development (Ibrekk et al. 1993). Several projects have been initiated to improve the accuracy of the LENKA. a mathematical model called “Fjordmilφ”, has been developed (Ibrekk 1993), which gives a quantitative estimate of eutrophication effects of fish farming in fjords. The model gives a quantitative estimate that is considered to be more reliable than the indices used in the LENKA model. The next step in the direction of coastal zone management, site selection for marine fish farming and environmental protection, is development of another concept of management system called MOM (Modelling-On growing fish farms-Monitoring), which is designed to maintain satisfactory environmental conditions in and around fish farms and may be a valuable tool in site selection and coastal zone management. It is directed towards adjustment of the local environmental impact of marine fish farming, specific to the conditions of culture practice and the holding capacity of the sites. The concept is based on integrating the elements of environmental impact assessment, monitoring of impact, and environmental quality into one system (Ervik et al.1997). This forms the core concept on which is based the management framework of GESAMP (1996) discussed earlier. The MOM concept although deals with the local environment impact of marine fish farms, has a functional overlapping with LENKA as regard monitoring of impact in the regional impact zone 11
  • 12. is concerned. The precise monitoring of the impacts under MOM would provide an opportunity for better assessment of holding capacity under LENKA. The following applications for the MOM system have been advocated (Ervik et al. 1997). 1. Simulation of environmental impact of a fish farm on a given site. 2. Adjustment of farming practices to prevent impact from exceeding the EQSs. 3. Assessment of relative differences between sites in terms of holding capacity. 4. Assessment of relative differences between various arrangements of net cages in terms of nutrient loading and dispersion. 5. MOM could be used in conjunction with LENKA for Coastal Zone Management. Sustainable marine farming system also need to address the problems imposed by availability of feed stuff such as the stock of pelagic fishes upon which, the fish meal industry is based ( Baird et al. 1996). Given the holding capacity of a marine area, there may be alternatives in terms of technology of cage fish farming to select from. It is logical to conclude that such alternatives involving improvement in terms of nutrient loading, waste recovery and nutrient recycling would put the given marine cage farming site to better use. It would thus permit comparative assessment of holding capacity of a given marine area, cost of production and economics of operation in terms of technological development. 12
  • 13. Methodology The Objectives The present study has been designed to study the following issues: 1. Assessment of nutrient loading from five selected salmon farming technologies using different type of feed, feeding technique and waste recovery mechanism. 2. Comparative assessment of production potentials of representative Norwegian marine sites deploying alternate farming systems. 3. Comparative assessment of the cost of production and economics of salmon farming following the five different production techniques. 4. Utilizing the nutrient loading and economic performances of the production systems in drawing up strategy for coastal zone planning addressing one or more of the following issues: i. maximizing fish production using least polluting technology, ii. maximizing return from a given area by adopting production system generating maximum profit margin iii. adopting least cost production system for a better market share of the product. The Study Plan 1. The Production Potentials Comparative assessment of production potentials of representative Norwegian marine sites deploying alternate farming systems falling in ‘A’-category zone in Northern Norway using alternate technologies has been attempted. These technologies offer varying scope for reduction in nutrient loading and waste recovery. Production potentials of Norwegian coastal zone as assessed under the LENKA system (Ibrekk, 1993) has been considered. The traditional farming system with defined nutrient loading and production potential provides the bench mark for assessment of ‘Holding Capacity’ and ‘Area Capacity’ of the Norwegian coastal waters, and the same has been adopted here for assessment of the production potentials using alternate farming technology. The ‘Holding Capacity’ assessment is based on nutrient loading from salmonid farming, general knowledge of the marine environment and detailed studies of areas with intensive aquaculture activity (Aure and Stigebrandt 1989). The ‘Area capacity’ is primarily calculated based on the marine area in a zone available for aquaculture, excluding areas unsuitable for aquaculture and areas already used or reserved for other purposes. The net area is converted to production potentials using the standard set for Norwegian waters (Ibrekk, 1993). The ‘Area Capacity’ so assessed is matched with the ‘Holding Capacity’ and lower of the two values would determine the gross available capacity for future planning (Figure 1). Thus as may be evident, the production potential is key to the assessment of ‘Holding Capacity’ and ‘Area Capacity’ of the marine sites and the same has been quantified based on average fish farm’s standard production of 25 kg /m3 (300 tons of fish produced per 12000 m3). With a feed 13
  • 14. conversion ratio of 1.5, annual loading from an average farm has been estimated to be 3 tons total phosphorus, 27 tons total nitrogen and approximately 150 tons of organic matter (Ibrekk, 1993). It is expected that the production potential would undergo upward change with reduction in nutrient loadings. This in turn would enhance the Area Capacity’ and the ‘Holding Capacity’ and the consequent ‘Gross Available Capacity’ for future planning. 2. Assessment of Nutrient Load Discharge of nutrients and organic material is inevitable in open cage system. The main factors involved in the process are 1. the volume of production, 2. the feeding technology, 3. the quality of feed and 4. the waste mitigating measures deployed. Hence a comparative analysis of nutrient loading for the following salmon cage farming systems was done using available data. • Traditional Farming System using conventional feed and feeding mechanism • Improved Farming System using efficient feed and feeding mechanism • Improved Farming System using HND feed and efficient feeding mechanism • Farming System using efficient feed and Lift-up feed collector • Closed Bag Integrated Farming System The systems under reference differs from the point of view of factors influencing nutrient loading. The factors influencing nutrient loading are as under. • Feed quality • Feeding method • Waste recovery • Nutrient recycling (Biological Waste Recovery) The factors influencing nutrient loading have thus been taken into consideration in the present study through selection of the above technologies. These factors influencing the nutrient loading are discussed followed by methodology for assessment of the waste loading . 3. Comparative Economics The cost of production of salmon was worked out following the Norwegian case studies on Atlantic salmon (Bjdrndal 1990) and information collected during field study conducted in connection with the present project work. The comparative economics of the farming systems under consideration was studied using discounted cash flow technique as developed by the Economic Development Institute, International Bank for Reconstruction and Development (Gittinger 1981). 4. Development Strategy The variations in nutrient loading between the farming systems have been utilized to assess their production potentials. Selection of the least impact farming system is expected to result in maximization of production from a given marine area with known holding capacity. 14
  • 15. The comparative study of the IRR of the farming systems would provide an opportunity to maximize return by proper selection of technology with or without maximizing production. Least cost production is an important criteria in marketing the product and hence an assessment of this parameter is necessary. Even though we may hit upon a least polluting farming system however its applicability would be ultimately determined by the marketing factor such as cost of production. The Farming Systems i. Traditional Farming System using conventional feed and feeding mechanism (System 1) Considering the Norwegian regulations, farm size of 12000 m3 has been considered with overall production limit of 300 tons. A wide variety of cage designs has been developed over the last 20 years; however, the common features are a floating collar, usually rectangular, a suspended net bag and a mooring system. In the present study steel cage system has been considered (Fig.2a & 2b). The design of cage which is frequently used in Scottish and Norwegian farms, comprises a square or rectangular frame of cage superstructure with walkways in between rows of cages. A steel handrail about 0.75m high, is attached to the inside of the walkway, and from this, the cage bag is suspended. Typically, the cages are connected to each other with ropes and shackles to form a floating rectangular raft of 15-20 individual cages with a central walkway. The raft is moored to the sea bed or to the shore using anchors, chains, ropes and shock-absorbing systems. In the present case 16 cages with cage volume of 800 m3 each have been considered of which 15 would be under production with one stand-by cage. Thus the effective production volume is estimated to be 12000 m3. Considering a stocking rate of 7.5 smolt / m3, 85% survival and an average harvest weight of 4kg salmon, the final harvest is expected to be 300 kg. The production is based on the assumptions under ‘LENKA’ system. The feeding system is considered to be automatic feeder type based on a feeding program pre-set by the farmer to dispense dry pellet as discussed subsequently. A 12V battery and a control unit connected through cabling along walkways and cage superstructure can regulate feeding in number of cages adopting centralized feeding. Feeding is synchronized in all the cages using the timing device. In the traditional Farming System use of conventional feed with FCR value of 1.5 (‘N’= 8%; ‘P’ = 1%) has been considered corresponding to nutrient loading under ‘LENKA’ system. ii. Improved Farming System using efficient feed and feeding mechanism (System 2) The farming system is similar to the earlier system excepting for the feeding system, type of feed used and the production program. In this system improved feed with FCR value of 1.0 (‘N’= 7.5%; ‘P’ = 0.9%) has been considered. A strict feeding regime is envisaged using computer aided ‘Adaptive Feeding System’ that controls automatic feeders by accurately matching feed delivery to fish appetite. The Aquasmart AQ1 with advanced sensor, communications system and software is one such system with which an entire farm can be monitored and controlled from a 15
  • 16. centrally located PC (Fig.3). This enables minimising feed loss to the extent of 4% of total nutrient supply. The production program is based on the production potentials of such cage systems under Norwegian conditions as described by Bjdrndal (1990). Accordingly a cage volume of 12000 m3 is expected to produce 370 tons of fish, stocked at the rate of 10 smolt/ m3 with 15% survival and average weight of 3.7 kg/fish. iii. Improved Farming System using HND feed and efficient feeding mechanism (System 3) The farming system is similar to the earlier system excepting for the type of feed used. In this system high energy nutrient dense diet with FCR value of 0.83 (‘N’= 7.2%; ‘P’ = 0.9%) has been considered. The low-protein, high-fat composition of these feeds with protein sparing effect is expected to reduce protein catabolism and utilize the same for anabolic process thus improving FCR while reducing excretion of nitrogenous products. A strict feeding regime is envisaged using computer aided ‘Adaptive Feeding System’ as in the case of the earlier system. The production program is also similar to the previous system. iv. Farming System using efficient feed and Lift-up feed collector (System 4) The Lift-up Kombi system is provided with a fine meshed funnel shaped net cloth, which is provided under the cage to which a tube is attached at the bottom to remove dead fish, excess feed and large faecal particles. These are collected by lifting the water from the bottom of the cage using the water lift and passed through the filtration unit that retains the particulate matter. The Lift-up Kombi system is known to collect upto 100% surplus feed, sized 6 mm and larger and nearly 70% of 4 mm particles (Ervik et al, 1994). The description of the system is presented subsequently. From the farming system point of view it is similar to system2. It is based on use of the same feed and feeding system as well as production programme as in system2. The additional feature being the reuse of waste feed and removal of particulate faecal matter. v. Closed Bag Integrated Farming System (System 5) The concept of clean technology is based on principles of waste removal deploying biological process that would take care of the particulate matter and the dissolved nutrient, generated on account of uneaten feed, undigested feed and excretion. Integrating farming of mussels and seaweed with fish is known to be very effective in recycling nutrients and wastes. In fact such floating enclosed system has been developed and tested in full-scale for the last 8 years in Norway. A theoretical model linking the production of salmon, blue mussel and seaweed in floating enclosed unit was performed during 1992-94 to minimize eutrophication from fish farming activities (Bodvin et. al.1996). Detail description of the model is discussed subsequently. The model plant is based on production data from a full-scale pilot farm built in Flekkefjord (Skaar & Bodvin, 1993) as described by Bodvin et.al. (1996). The standard plant with production volume of 6000 m3, consisting of 12 fish units, each with a volume of 500 m3is linked to 12 mussel units which in turn is linked to 12 seaweed units. The fish unit with stocking rate of 15 smolt m3 and 85% survival is estimated to produce 300 tons of fish. In order to trap the particulate emissions from the fish unit 1350 tons (fresh weight) of mussel is required. The dissolved outflow from the fish unit as well as the mussel unit is estimated to support 3000 tons 16
  • 17. of seaweed. With the removal of the particulate emissions from the mussel unit, the filtered water emerging from the seaweed unit is rendered waste-free. The Factors Influencing Nutrient Loading Feed Quality The feed coefficient and the content of phosphorus (‘P’) and nitrogen (‘N’) in the feed are two important factors to consider while assessing environmental impact of aquaculture (Ackefors, 1997). Mass balance models have shown that the discharge of nutrients and organic materials have decreased over the past two decades owing to reduction in feed conversion ratio and content of nitrogen and phosphorous in commercial salmon feed. While the feed coefficient has decreased from 2.3 to less than 1.3, the nitrogen content in the feed has decreased from 7.8% to 6.8% and that of phosphorous from 1.7% to 1.1% (Ackefors and Enell, 1990). This has resulted in lowering of discharge of nutrient per tine of produced fish. In case of nitrogen it has decreased from 129 kg to 53 kg and for phosphorus from 31 kg to 9.5 kg (Ackefors, 1997). In recent days FCR as low as 0.85 has been reported. Thus feed quality is an important factor in lowering of environmental impact of marine cage fish farming. In the present study, three different feeds have been selected for assessment of nutrient loading of the chosen technologies. In the traditional Farming System use of conventional feed with FCR value of 1.5 (‘N’= 8%; ‘P’ = 1%) has been considered. Though present day feed are much lower in ‘N’ & ‘P’ content however the assessment of ‘Area Capacity’ under ‘LENKA’ is based on this kind of feed and hence for the shake of comparison it was necessary to include this as control. The improved feed with FCR value of 1.0 (‘N’= 7.5%; ‘P’ = 0.9%) has been considered for the remaining technologies excepting one in which HND diet has been considered. FCR for the HND diet is taken as 0.83 (‘N’= 7.2%; ‘P’ = 0.9%). Thus it would be possible to compare the least efficient feed with quality feed and the nutrient dense feed. The quality feed has also been considered as the basis for mass balance modeling of the two technologies concerning i.waste recovery (Lift-up) and ii. nutrient recycling (Integrated farming). Feeding Feeding is one of the most important and expensive jobs in salmon farming. The main aim of the farmer is to achieve maximum growth from the food that is fed. No food has to be wasted as this can have a detrimental effect not only on the profitability of the farm, but also on the seabed beneath the cages. In modern day salmon farming there are three methods of administering the food to the fish. These are: 1. Feeding till Satiation A. Hand feeding. Following this method feed release is triggered by fish behavior and hence feeding is to satiation level. In this kind of feeding practice, the operative would be feeding the fishes manually by broadcasting the feed while moving from cage to cage. The farmer determines how much food is to be fed to a pen by working out the biomass of the fish within the cage. A certain percentage of this biomass is then fed to the fish daily. This percentage figure varies throughout the year and is dependant upon fish size, seawater temperature and the stock type as well as the experience of the operative in feeding the fishes. For Semi-intensive cage farming, hand feeding may be the best method since it is possible to assess fish appetite and adjust feeding rates however it may 17
  • 18. result in overfeeding since the end point in this method is usually the point where fish stop eating. However the down side of this mode of feeding is higher labor cost and its application on large- scale commercial application. B. Demand Feeding It is a mechanical form of feeding based on the feeding behavior of the fish. Demand feeders typically consist of a feed hopper fitted with a plate that is connected to the pendulum rod that projects down into the water. When the pendulum is touched, the plate moves thereby releasing small quantities of feed. The fish can feed whenever it wants but the method could be wasteful in sea condition where, the pendulum could be stimulated by wave actions. It is more commonly used in the land-based than water-based systems (Beveridge 1996). 2. Automatic Feeding Automatic feeders depends on a feeding program pre-set by the farmer indicating ration and frequency of delivery. The farmer determines how much food is to be fed to a pen by working out the biomass of the fish within the cage. A certain percentage of this biomass is then fed to the fish daily. This percentage figure varies throughout the year and is dependant upon fish size, seawater temperature and the stock type. Dry pellet automatic feeders typically consists of a plastic feed hopper mounted on a triggering device that releases a certain quantity of feed when triggered. These are operated either by batteries or by compressed air / pressurized water (Beveridge 1986). Electrical The electrically operated systems are operated either using centralized power supply with common control unit or using individual power source and control device for independent operating of each unit. The control unit sends the required electrical impulse determining the number and duration of feeding. The operation of the feeders during daytime is ensured using a photocell. A number of cages adopting the centralized feeding can fed by a 12V battery and a control unit connected through cabling along walkways and cage superstructure. Feeding is synchronized in all the cages using the timing device. Compressed air / pressurized water system Cannon feeding is based on either compressed air or pressurized water system. Compressed air is less popular at cage sites. The compressor pressurizes an air chamber, from which bursts of air is released and fed via high-pressure pipeline connecting the feeders on the cages. The feeders consist of a hopper from which pellets fall into a delivery pipe connected to the compressed air line. When air is released into the delivery pipe pellets are blown into the cages. Compressed air feeders can operate from boat or from shore based facility (when the cages are linked by catwalk to the shore based facilities). Pressurized water systems are also used to deliver food from a centralized unit via pipeline to individual cages (Fig.4). While automatic feeding system is less labor intensive than hand feeding, it is found to be wasteful from feed utilization point of view. Thus it may result in higher feed conversion, feed cost and nutrient loading (Beveridge, 1996) 18
  • 19. 3. Computer controlled strict feeding Regime These are relatively new adaptive feeding systems and are responsive to changes in the environment and hence an improvement over the automatic feeding system relying heavily on pre-set feeding program. These systems consist of a hydroacoustic or video sensor attached to the bottom of the cage net which is linked to a computer (Juell 1991, Juell et. al.1993; Bjordal et. al. 1993; Blyth 1992). A feeding program is preset so that a certain amount of food is fed in a certain amount of meals. If the fish are being overfed then the sensor picks up the uneaten food reaching the bottom of the pen and sends the information back to the computer, which in turn reduces the amount of food fed. Conversely the computer will increase feed input until feed pellets are detected at the bottom of the pen. Using these systems feed wastage can be reduced to 4% level and greatly improves FCR (Baird et al. 1996). Some of the most effective types of feeding systems are the ones manufactured by Aquasmart and AKVA. Three computer aided feeding systems based on hand feeding, cannon feeding and adaptive fish feeding techniques developed by Aquasmart is discussed here. i. Aquasmart PS1 Feed Monitoring System The features of PS1 Feed Monitoring System (Fig.5) are as under: • PS1 can be used with hand feeding, feed cannons, or centralized feeding systems • an underwater sensor which detects pellet sizes from 2mm to 16mm • temperature tolerance from -20 to +50 degrees Celsius • internal 12V DC battery with 100 to 240V AC recharge • radio communication • Windows-based software • and can be integrated with all centralized feeders ii. Aquasmart PS2 Feeding Control System for Feed Cannons The PS2 software can also be linked to feed cannons to record feeding rate during the meal. As the feed operator feeds the fish, the PS2 unit (Fig.6) sends information gathered by the sensor via telemetry to the computer. From here the operator can adjust the feed in relation to the appetite of the fish. If the feeding rate is too high an alarm sounds to warn the operator. iii. Aquasmart AQ1 Adaptive Fish Feeding System The AQ1 Adaptive Feeding System controls automatic feeders by accurately matching feed delivery to fish appetite. The AQ1 advanced sensor, communications system and software means an entire farm can be monitored and controlled from a centrally located PC (Fig. 7). This advanced feed optimization system features: • an underwater sensor which detects pellet sizes from 2mm to 16mm • temperature tolerance from -20 to +50 degrees Celsius • radio communication • Windows-based software • creating a complete management record of feeding Using the feeding systems based on feeding behaviour of the fish that reflects its satiation level, we may be relying on the hypothalamus control of the fish. This physiological control is stimulated by the stretch receptors in the fore-end of the gut and possibly by the blood sugar 19
  • 20. level. Such natural physiological controls have evolved to deal with the natural food encountered in the wild. However, the nutrient content of the artificial feed being of much higher order, the supply of nutrient may be much higher than required resulting in poor FCR (Beveridge 1996). The hand feeding and the use of feed cannon are based on the above concept accounting for greater feed waste estimated to be 20% of total feed supply. The automatic feeding control systems used in conjunction with the above feeding systems is likely to have a check on the total food supply through its pre-set computer controlled feeding program as well as its monitoring system scanning the cage volume for detection of unutilised feed particles. This enables minimising feed loss to the extent of 4% of total nutrient supply. Mechanical Waste Recovery Approximately 25% of nitrogen and 75% of phosphorus wastes from open fish cage systems appear in particulate form (Hall et.al 1990; Gowen et al 1988 and Ackefors et al 1990). Mass balance models for organic carbon indicates that 7 to 66% of it is sedimented under the cages (Ackefors, 1997). Several mechanical devices have been designed to collect this particulate fraction of the wastes generated from the cage sites, which include i. Viking fish model by the Swedish company (Viking fish AB), ii. the Refa lift-up pellet sampler by a Norwegian company and iii. the Lift-up Kombi waste feed and dead fish collector (Enell et al 1984; Braathen 1992; and Ackefors, 1997). The Lift-up Kombi system is provided with a fine meshed funnel shaped net cloth, which is provided under the cage to which a tube is attached at the bottom (Fig.8). To this is attached the compressed air pipe, providing the air lift suction. Dead fish, excess feed and and large faecal particles are trapped by the lower fine-meshed net and led to the bottom of the net where a hose is connected. The waste food is collected by lifting the water from the bottom of the cage using the water lift and passed through the filtration unit that retains the particulate matter. The sludge can be used as manure (Ackefors, 1997). The Lift-up Kombi system is known to collect upto 100% surplus feed, sized 6 mm and larger and nearly 70% of 4 mm particles (Ervik et al, 1994). It is stated that “ The surplus feed collector can also reduce the general impact of fish farms on their recipients. This is most important for marginal recipients, since the life span of these locations are increased significantly. The negative environmental feedback on fishfarm in such environment will be diminished, - instead of resulting in poor health conditions and high needs of antibacterials. The higher cost of the equipment are shown to be balanced by the benefits of automatic dead fish collection, increased growth, reduced feed conversion rates and lower mortality of the fish.” Recovery of waste using Lift-up system can be based on the following assumptions. • Approximately 25% of nitrogen wastes from open fish cage systems appear in particulate form • Approximately 75% of phosphorus wastes from open fish cage systems appear in particulate form • Approximately 80% of the particulate matter emitted from the cages are collected by the Lift-up systems Using the data on nutrient load derived from mass balance equation and the above information, the recovery of nutrients can be calculated using the following expression wherein, ‘R’ is 20
  • 21. recovery of nutrient; ‘P’ is % particulate form, ‘r’ is % recovery and ‘NL’ is nutrient load from the system. R = NL x P/100 x r/100 The recovery of wastes using the Lift-up system would depend on the nutrient content of the feed itself. In the present study improved feed with FCR of 1.0 has been considered since this form the basis of present day farming practice. Nutrient Recycling (Biological Waste Recovery) The basic pre-requisite for sustainable salmon farming would be use of clean technology based on principles of minimum nutrient / waste loading on the surrounding aquatic environment. Since production of organic wastes can not be avoided hence a clean system would either remove it mechanically or use it up within the production system itself. The goal must be a production process where the water is used only as a carrier which leaves the production plant ‘untouched’ by the production process (Bodvin et.al. 1996). This can be achieved by employing biological process that would take care of the particulate matter and the dissolved nutrient, generated on account of uneaten feed, undigested feed and excretion. Integrating farming of mussels and seaweed with fish is known to be very effective in recycling nutrients and wastes (Figure 9). Using filter feeders such as mussel / oyster / clam for reducing particulate matter and macro-algae for removing dissolved nutrient is known to be an effective biological alternative. However, this can only be effective in an enclosed system (Shpigel et al. 1993) and results from production of salmonides, mussels and macro-algae indicate such possibilities (Bodvin et.al. 1996). In fact such floating enclosed system with 50 – 60 % lower investment cost and reduced energy expenditure has been developed and tested in full-scale for the last 8 years in Norway. A theoretical model linking the production of salmon, blue mussel and seaweed in floating enclosed unit was performed during 1992-94 to minimize eutrophication from fish farming activities. Commercial viability of such aquaculture technique is expected to enable the industry to meet the Declaration of The North Sea. The model plant is based on production data from a full scale pilot farm built in Flekkefjord (Skaar & Bodvin,1993) as described by Bodvin et.al. (1996). The standard plant with production volume of 6000 m3, consisting of 12 fish units, each with a volume of 500 m3 and pumping capacity of 5.5 m3 min-1 delivers the particulate and dissolved emissions to the next unit, which is the mussel unit. Outlet water is transferred from the salmon units to 12 enclosed units (500 m3 each) with blue mussels using airlift system. The outlet is set to 50 kg total ‘N’ and 8 kg of total ‘P’ per metric ton of salmon produced. Of this the mussel units are designed to convert 25% of particulate ‘N’ and ‘P’ emissions. The dissolved ‘N’ and ‘P’ emissions from the salmon as well as mussel units are transferred to the seaweed units. The particulate wastes from the mussel units are collected in sediment trap and removed. The stocking rate of mussel is worked out considering i. all water has to be pumped at least once and that would require a pumping capacity three times larger than the water flux and ii. the standard pumping capacity of 2-3 l h-1 for a standard market size mussel weighing 25 g. The required mussel was thus assessed to be 112.5 metric tons or 9.4 metric tons fresh weight (FW) per unit or 18 kg FW per m-3. With a monthly exchange of mussels in each unit, the total turnover is assessed to be 1350 metric tons. In this model no specific estimates for a mass balance with mussel concerning total ‘P’ are used and the same is assessed using the principles for the fish unit. Seaweed production has been modelled on the basis of total utilisation of the dissolved ‘N’ by the seaweed unit. Considering a ‘N’-content of 4% for seaweed dry weight and 20% dry matter content, a total production of 1700 metric tons fresh weight (FW) of seaweed year-1 is envisaged. This in turn is based on the assumption of 4.5 metric tons of seaweed production day-1 requiring 45 metric ton of standing stock with a daily 21
  • 22. growth rate of 10%. With 12 production units of 1000 m3, the standing stock would amount to 3.75 kg FW m-3. Considering the ‘P’-content in seaweed ( 0.2%) and dry matter content (20%), a production of about 3000 metric tonne is envisaged (Bodvin et. Al.1996). The mass balance equations for this biological system is discussed subsequently (table 14-20). Waste Quantification There are two methods for estimating material lost to the environment i.e. 1. Direct method, involving sampling and analysis of the water column and sedimenting particulate material 2. Indirect method, using mass balance equation. In the present study, mass balance equation has been used for quantifying the waste load from the selected farming systems under consideration. Following Mass Balance Equation assessment of nutrient loading in terms of Nitrogen (‘N’), Phosphorus (‘P’) and Total Solids (TS) from salmon cage farming were made. Nutrient loss through uneaten food, faecal matter and excretion can be estimated using data on feed quality and quantity, food conversion ratio (FCR), digestibility and faecal composition. The present assessment of Nitrogen and Phosphorus flow through salmonid cages has been based on the works of Beveridge (1984), Ackefors and Enell (1990) and Holby and Hall (1991). The flow chart of nutrients from feed to fish and finally to the environment as wastes is shown in Figure 10-12. As is evident from this chart, given the information on Fish Production, Feed Conversion Ratio, Feed Waste (%) and, Feed digestibility (%) derived parameters such as Feed Supply, Feed Consumed, Fecal Production can be worked out. Further, information on nutrient content of feed, nutrient content of feces and nutrient in fish biomass would enable assessment of nutrient loading. Thus total nutrient loading (NL) could be derived using the following equation wherein ‘NS’ stands for nutrient supply in feed and ‘NR’ stands for nutrient retained in fish . NL = NS - NR Information on solid wastes by way uneaten feed and feacal production could be utilized to work out the load on account of suspended solids as under. TSS = UF + FP ‘TSS’ stands for Total Suspended Solids, ‘UF’ for Unconsumed Feed ‘FP’ stands for Fecal Production. 22
  • 23. Results The results of the study is presented in three sections 1. Mass Balance analysis 2. Production Potential assessment and 3. Economics of production using the cage systems under reference (Table 1). Table 1. Cage Systems Under Consideration Item System1 System2 System3 System4 System5 Site type A category of A category of A category of A category of A category of Northern Northern Northern Northern Northern Norway Norway Norway Norway Norway Type of Farm Floating unit Floating unit Floating unit Floating unit Floating unit 3 3 3 3 3 Cage volume 12000m 12000m 12000m 12000m 6000m Cage type Steel cage Steel cage Steel cage Steel Cage* Closed bag** 3 3 3 3 3 Cage size 800m 800m 800m 800m 500m No. ofCage 16 16 16 16 12 No.of nets 16 16 16 16 0 Water Flow Natural flow of Natural flow of Natural flow of Natural flow of Flow on account sea water sea water sea water sea water in of Air-lift of addition to flow water from fish due to air-lift unit to mussel and to seaweed Stocking rate of 7.5 10 10 10 15 smolt/ m3 Duration of 24 24 24 24 24 rearing (months) Mortality 15 15 15 15 15 Production in MT 300 370 370 370 300 Type of Feeding Automatic Aquasmart Aquasmart Automatic Automatic system feeder adaptive adaptive feeding feeder feeder feeding system system Type of Feed Dry pelleted Improved feed HND diet Improved feed Improved feed (FCR:1.5) (FCR:1.0) (FCR:0.83) (FCR:1.0) (FCR:1.0) Feeding principle Feeding to Strict feeding Strict feeding Feeding to Feeding to satiation regime regime satiation satiation Feed Waste 20% 5% 5% 4% 10%*** Special Feature if Designed to Represents Indicates the The possibilities Biological any meet the The existing impact of further of mechanical solution to norms under farming system improvement in recovery of nutrient loading ‘LENKA’ feed quality waste feed system Processing Hired Hired Hired Hired Hired facility Packaging Hired Hired Hired Hired Hired facilities *Lift up Kombi system to meet Norwegian Govt Regulation **Refers to close bag system (Bodvin,1996), built in Flekkefjord in 1990 ***There is apparent feed wastage, which although not eaten by fish, is removed by the filter feeders System1= Traditional farming system with conventional feed (FCR: 1.5) & no feeding control System2= Farming System with improved feed (FCR: 1.0) & strict feeding regime System3= Farming System with HND feed (FCR: 0.83) & strict feeding regime System4= Farming System with Lift up feed system System5= Integrated farming involving fish, mussel & sea weed 23
  • 24. Mass Balance Analysis i. Traditional Farming System using conventional feed and feeding mechanism (System) Following the traditional system 16 cages with cage volume of 800 m3 each have been considered of which 15 would be under production with one stand-by cage. Thus the effective production volume is estimated to be 12000 m3. Considering a stocking rate of 7.5 smolt / m3, 85% survival and an average harvest weight of 4kg salmon, the final harvest is expected to be 300 kg. The use of automatic feeder type with pre-set feeding program would ensure feeding till satiation but since it is not adapted to regulate feeding on the basis of behavioral response of the fish, considerable feed wastage)(20%) is involved in this mode of feeding. In the traditional Farming System use of conventional feed with FCR value of 1.5 (‘N’= 8%; ‘P’ = 1%) has been considered following the provisions under ‘LENKA’ system. The mass balance analysis of nitrogen, phosphorus and suspended solids have been worked out (table 2-4) Table 2. Mass Balance Equation for Nitrogen (System 1) Sl.No Items Formula Estimation . 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1.5 3 Feed Supply (kg) C=AxB 1500 4 Feed Wastage (%) Dw 20 5 Feed Waste (kg) D = C x Dw / 100 300 5 Feed Consumed (kg) E = C (100 – Dw)/ 100 1200 6 Feed Undigested (%) F 25 7 Fecal Production (kg) G = E x F / 100 300 8 Nitrogen Content of Feed (%) H 8 9 Nitrogen Content of Feces (%) I 4 10 Nitrogen in Feed Supply (kg) J = C x H / 100 120 11 Nitrogen in Feed Waste (kg) K = D x H / 100 24 12 Nitrogen Ingested (kg) L = E x H / 100 96 13 Nitrogen Retained in Fish @ 3% (kg) M = A x 3 /100 30 14 Total Nitrogen Excreted (kg) N=L–M 66 15 Nitrogen in Feces (kg) O = G x I / 100 12 16 Nitrogen in Catabolic Product (kg) P=N–O 54 17 Total Nitrogen Load (kg) Q=K+O+P 90 18 Recovery of Nitrogen Load if any (kg) R 0 19 Net Nitrogen Load on environment (kg) S=Q-R 90 24
  • 25. Table 3. Mass Balance Equation for Phosphorus (System 1) Sl.No Items Formula Estimatio . n 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1.5 3 Feed Supply (kg) C=AxB 1500 4 Feed Wastage (%) Dw 20 5 Feed Waste (kg) D = C x Dw / 100 300 5 Feed Consumed (kg) E = C (100 – Dw)/ 100 1200 6 Feed Undigested (%) F 25 7 Fecal Production (kg) G = E x F / 100 300 8 Phosphorus Content of Feed (%) H 1 9 Phosphorus Content of Feces (%) I 1.5 10 Phosphorus in Feed Supply (kg) J = C x H / 100 15 11 Phosphorus in Feed Waste (kg) K = D x H / 100 3 12 Phosphorus Ingested (kg) L = E x H / 100 12 13 Phosphorus Retained in Fish @ 0.4 % (kg) M = A x 0.4 /100 4 14 Total Phosphorus Excreted (kg) N=L–M 8 15 Phosphorus in Feces (kg) O = G x I / 100 4.5 16 Phosphorus in Catabolic Product (kg) P=N–O 3.5 17 Total Phosphorus Load (kg) Q=K+O+P 11 18 Recovery of Phosphorus Load if any (kg) R 0 19 Net Phosphorus Load on environment (kg) S=Q-R 11 Table 4. Mass Balance Equation for Total Solids (System 1) Sl.No Items Formula Estimate . 1 Unconsumed Feed (kg) D = C x Dw / 100 300 2 Fecal Production (kg) G = E x F / 100 300 3 Total Solid Load (kg) H=D+G 600 4 Recovery of Solid Load if any (kg) R 0 5 Net Solid Load on environment (kg) S=H-R 600 Following the traditional farming system the expected nutrient load on the environment on the basis of mass balance analysis amounts to 90 kg Nitrogen, 11 kg phosphorus and 600 kg solid waste (Fig.13). ii. Improved Farming System using efficient feed and feeding mechanism (System 2) In this system improved feed with FCR value of 1.0 (‘N’= 7.5%; ‘P’ = 0.9%) has been considered. A strict feeding regime is envisaged using computer aided ‘Adaptive Feeding System’ that controls automatic feeders by accurately matching feed delivery to fish appetite. This enables minimising feed loss to the extent of 4% of total nutrient supply. In this model feed wastage to the extent of 5% has been considered. The production program is based on a cage volume of 12000 m3 that is expected to produce 370 tons of fish, stocked at the rate of 10 smolt/ m3 with 15% survival and average weight of 3.7 kg/fish. The mass balance analysis of nitrogen, phosphorus and suspended solids have been worked out (table 5-7). 25
  • 26. Following the Improved farming system involving quality feed and adaptive feeding technique the expected nutrient load on the environment using mass balance analysis is estimated to be 45kg Nitrogen, 5 kg phosphorus and 240 kg solid waste (Fig.14). A better food conversion and reduced nutrient loss is achieved compared to system 1 on account of better feed utilization nutrient profile. Table 5. Mass Balance Equation for Nitrogen (System 2) Sl.No Items Formula Estimation 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1 3 Feed Supply (kg) C=AxB 1000 4 Feed Wastage (%) Dw 5 5 Feed Waste (kg) D = C x Dw / 100 50 5 Feed Consumed (kg) E = C (100 – Dw) / 100 950 6 Feed Undigested (%) F 20 7 Fecal Production (kg) G = E x F / 100 190 8 Nitrogen Content of Feed (%) H 7.5 9 Nitrogen Content of Feces (%) I 4 10 Nitrogen in Feed Supply (kg) J = C x H / 100 75 11 Nitrogen in Feed Waste (kg) K = D x H / 100 3.75 12 Nitrogen Ingested (kg) L = E x H / 100 71.25 13 Nitrogen Retained in Fish @ 3% (kg) M = A x 3 /100 30 14 Total Nitrogen Excreted (kg) N=L–M 41.25 15 Nitrogen in Feces (kg) O = G x I / 100 7.6 16 Nitrogen in Catabolic Product (kg) P=N–O 33.65 17 Total Nitrogen Load (kg) Q=K+O+P 45 18 Recovery of Nitrogen Load if any (kg) R 0 19 Net Nitrogen Load on environment (kg) S = Q - R 45 Table 6. Mass Balance Equation for Phosphorus (System 2) Sl.No Items Formula Estimatio . n 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1 3 Feed Supply (kg) C=AxB 1000 4 Feed Wastage (%) Dw 5 5 Feed Waste (kg) D = C x Dw / 100 50 5 Feed Consumed (kg) E = C (100 – Dw)/ 100 950 6 Feed Undigested (%) F 20 7 Fecal Production (kg) G = E x F / 100 190 8 Phosphorus Content of Feed (%) H 0.9 9 Phosphorus Content of Feces (%) I 1.5 10 Phosphorus in Feed Supply (kg) J = C x H / 100 9 11 Phosphorus in Feed Waste (kg) K = D x H / 100 0.45 12 Phosphorus Ingested (kg) L = E x H / 100 8.55 13 Phosphorus Retained in Fish @ 0.4 % (kg) M = A x 0.4 /100 4 14 Total Phosphorus Excreted (kg) N=L–M 4.55 15 Phosphorus in Feces (kg) O = G x I / 100 2.85 26
  • 27. 16 Phosphorus in Catabolic Product (kg) P=N–O 1.7 17 Total Phosphorus Load (kg) Q=K+O+P 5 18 Recovery of Phosphorus Load if any (kg) R 0 19 Net Phosphorus Load on environment (kg) S=Q-R 5 Table 7. Mass Balance Equation for Total Solids (System 2) Sl.No Items Formula Estimation . 1 Unconsumed Feed (kg) D = C x Dw / 100 50 2 Fecal Production (kg) G = E x F / 100 190 3 Total Solid Load (kg) H=D+G 240 4 Recovery of Solid Load if any (kg) R 0 5 Net Solid Load on environment (kg) S=H-R 240 iii. Improved Farming System using HND feed and efficient feeding mechanism (System 3) In this system high energy nutrient dense diet with FCR value of 0.83 (‘N’= 7.2%; ‘P’ = 0.9%) has been considered. A strict feeding regime is envisaged using computer aided ‘Adaptive Feeding System’ as in the case of the earlier system. The production program is based on a cage volume of 12000 m3 that is expected to produce 370 tons of fish, stocked at the rate of 10 smolt/ m3 with 15% survival and average weight of 3.7 kg/fish. The mass balance analysis of nitrogen, phosphorus and suspended solids have been worked out (table 8-10). Table 8. Mass Balance Equation for Nitrogen (System 3) Sl.No Items Formula Estimation . 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 0.83 3 Feed Supply (kg) C=AxB 830 4 Feed Wastage (%) Dw 5 5 Feed Waste (kg) D = C x Dw/ 100 41.5 5 Feed Consumed (kg) E = C (100 – Dw)/ 788.5 100 6 Feed Undigested (%) F 18 7 Fecal Production (kg) G = E x F / 100 142 8 Nitrogen Content of Feed (%) H 7.2 9 Nitrogen Content of Feces (%) I 4 10 Nitrogen in Feed Supply (kg) J = C x H / 100 59.76 11 Nitrogen in Feed Waste (kg) K = D x H / 100 2.99 12 Nitrogen Ingested (kg) L = E x H / 100 56.77 13 Nitrogen Retained in Fish @ 3% (kg) M = A x 3 /100 30 14 Total Nitrogen Excreted (kg) N=L–M 26.77 15 Nitrogen in Feces (kg) O = G x I / 100 5.68 16 Nitrogen in Catabolic Product (kg) P=N–O 21.09 17 Total Nitrogen Load (kg) Q=K+O+P 29.76 18 Recovery of Nitrogen Load if any (kg) R 0 19 Net Nitrogen Load on environment (kg) S = Q – R 29.76 27
  • 28. Table 9. Mass Balance Equation for Phosphorus (System 3) Sl.No Items Formula Estimation . 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 0.83 3 Feed Supply (kg) C=AxB 830 4 Feed Wastage (%) Dw 5 5 Feed Waste (kg) D = C x Dw/ 100 41.5 5 Feed Consumed (kg) E = C (100 – Dw)/100 788.5 6 Feed Undigested (%) F 18 7 Fecal Production (kg) G = E x F / 100 142 8 Phosphorus Content of Feed (%) H 0.9 9 Phosphorus Content of Feces (%) I 1.5 10 Phosphorus in Feed Supply (kg) J = C x H / 100 7.47 11 Phosphorus in Feed Waste (kg) K = D x H / 100 0.37 12 Phosphorus Ingested (kg) L = E x H / 100 7.1 13 Phosphorus Retained in Fish @ 0.4 % (kg) M = A x 0.4 /100 4 14 Total Phosphorus Excreted (kg) N=L–M 3.1 15 Phosphorus in Feces (kg) O = G x I / 100 2.13 16 Phosphorus in Catabolic Product (kg) P=N–O 0.97 17 Total Phosphorus Load (kg) Q=K+O+P 3.47 18 Recovery of Phosphorus Load if any (kg) R 0 19 Net Phosphorus Load on environment (kg) S=Q-R 3.47 Table 10. Mass Balance Equation for Total Solids (System 3) Sl.No Items Formula Estimate . 1 Unconsumed Feed (kg) D = C x d / 100 41.5 2 Fecal Production (kg) G = E x F / 100 142 3 Total Solid Load (kg) H=D+G 183.5 4 Recovery of Solid Load if any (kg) R 0 5 Net Solid Load on environment (kg) S=H–R 183.5 Following this farming system involving high nutrient dense (HND) diet and adaptive feeding technique the expected nutrient load on the environment using mass balance analysis is estimated to be 29.76 kg Nitrogen, 3.47 kg phosphorus and 184 kg solid waste (Fig.15). A better food conversion and reduced nutrient loss is achieved compared to system 1&2. The low-protein, high-fat composition of these feeds with protein sparing effect help in reducing protein catabolism and consequent stimulation of anabolic process thus improving FCR while reducing excretion of nitrogenous and phosphorus wastes. iv. Farming System using efficient feed and Lift-up feed collector (System 4) The Lift-up Kombi system removes dead fish, excess feed and and large faecal particles. The Lift-up system is known to collect up to 100% surplus feed, sized 6 mm and larger and nearly 70% of 4 mm particles (Ervik et al, 1994). The present assessment is based on 80% recovery of waste feed and particulate ‘N’ and ‘P’ excretion. 28
  • 29. The production program is based on a cage volume of 12000 m3 that is expected to produce 370 tons of fish, stocked at the rate of 10 smolt/ m3 with 15% survival and average weight of 3.7 kg/fish. The mass balance analysis of nitrogen, phosphorus and total solids have been worked out (table 11-13). Table 11. Mass Balance Equation for Nitrogen (Lift up System) Sl.No Items Formula Estimation . 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1 3 Feed Supply (kg) C=AxB 1000 4 Apparent Feed Wastage (%) Da 20 5 Recovery of feed @ 80 % Rf = C x Da/100 x 160 80/100 6 Net feed waste (kg) D = (C x Da) – Rf 40 7 Net feed wastage (%) Dw = (D / C) x 100 4 8 Feed Consumed (kg) E = C (100 – Dw) / 100 960 9 Feed Undigested (%) F 20 10 Fecal Production (kg) G = E x F / 100 192 11 Nitrogen Content of Feed (%) H 7.5 12 Nitrogen Content of Feces (%) I 4 13 Nitrogen in Feed Supply (kg) J = C x H / 100 75 14 Nitrogen in Feed Waste (kg) K = D x H / 100 3 15 Nitrogen Ingested (kg) L = E x H / 100 72 16 Nitrogen Retained in Fish @ 3% B.W. M = A x 3 /100 30 17 Total Nitrogen Excreted (kg) N=L–M 42 18 Nitrogen in Feces (kg) O = G x I / 100 7.68 19 Nitrogen in Catabolic Product (kg) P=N–O 34.32 20 Total Nitrogen Load (kg) Q=K+O+P 45 21 Particulate Nitrogen Load (@ 25 %) (kg) Pn = Q x 25 / 100 11.25 22 Recovery of Particulate ‘N’ (@ 80%) Rn = Pn x 80 / 100 9 (kg) 23 Net particulate ‘N’ Load on environment Sn = Pn – Rn 2.25 (kg) 24 Dissolved Nitrogen Load (@ 75 % (kg) Dn = Q x 75 / 100 33.75 25 Total ‘N’ Load on environment (kg) Tn = Sn + Dn 36 Following lift-up system involving reuse of waste feed and recovery of particulate excretory matter, the expected nutrient load on the environment using mass balance analysis is estimated to be 36 kg Nitrogen, 2 kg phosphorus and 43 kg solid waste (Fig.16). Thus a reduction in nutrient loss is achieved when compared to system 1&2. The trend is somewhat different when compared to system 3 wherein, the emission of nitrogen is observed to be lower in system 3 but the emission of phosphorus and suspended solid is lower in system 4. This could be attributed to low generation of nitrogenous wastes in system 3 on account of protein sparing in HND diets and its low recovery in system 4 owing to lower particulate fraction (25%) compared to phosphorus and suspended solids. While the generation of phosphorus waste is actually higher in system 4, the lower loading is on account of substantial recovery of phosphorus in which particulate fraction is as high as 75%. 29
  • 30. Table 12. Mass Balance Equation for Phosphorus (Lift up System) Sl.No Items Formula Estimation . 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1 3 Feed Supply (kg) C=AxB 1000 4 Apparent Feed Wastage (%) Da 20 5 Recovery of feed @ 80 % Rf = C x Da/100 x 160 80/100 6 Net feed waste (kg) D = (C x Da) - Rf 40 7 Net feed wastage (%) Dw = (D / C) x 100 4 8 Feed Consumed (kg) E = C (100 – Dw) / 100 960 9 Feed Undigested (%) F 20 10 Fecal Production (kg) G = E x F / 100 192 11 Phosphorus Content of Feed (%) H 0.9 12 Phosphorus Content of Feces (%) I 1.5 13 Phosphorus in Feed Supply (kg) J = C x H / 100 9 14 Phosphorus in Feed Waste (kg) K = D x H / 100 0.36 15 Phosphorus Ingested (kg) L = E x H / 100 8.64 16 Phosphorus Retained in Fish @ 3% B.W. M = A x 3 /100 4 17 Total Phosphorus Excreted (kg) N=L–M 4.64 18 Phosphorus in Feces (kg) O = G x I / 100 2.88 19 Phosphorus in Catabolic Product (kg) P=N–O 1.76 20 Total Phosphorus Load (kg) Q=K+O+P 5 21 Particulate ‘P’ Load @ 75 % (kg) Pp = Q x 75 / 100 3.75 22 Recovery of Particulate ‘P’ (@ 80%) (kg) Rp = Pp x 80 / 100 3 23 Net particulate ‘P’ Load on Environment Sp = Pp – Rp 0.75 (kg) 24 Dissolved Phosphorus Load (@ 75 % Dp = Q x 25 / 100 1.25 (kg) 25 Total ‘P’ Load on environment (kg) Tp = Sp + Dp 2 Table 13. Mass Balance Equation for Total Solids (Lift-up System) Sl.No Items Formula Estimation . 1 Net feed waste (kg) D = (C x Da) - Rf 40 2 Net particulate ‘P’ Load on Env. (kg) Sp = Pp – Rp 0.75 3 Net particulate ‘N’ Load on Sn = Pn – Rn 2.25 environment (kg) 4 Net Solid Load on environment (kg) S = D + Sp + Sn 43 V. Closed Bag Integrated Farming System (System 5) The model plant is based on production data from a full scale pilot farm built in Flekkefjord (Skaar & Bodvin, 1993) as described by Bodvin et.al. (1996). The standard plant comprising 1. fish production section of 6000 m3 (12 fish units, each with a volume of 500 m3) linked to 2. mussel production section of 6000 m3 (12 mussel units, each with a volume of 500 m3), which in turn is linked to 3. seaweed section of 12000 m3 (12 seaweed units, each with a volume of 1000 m3). The fish unit with stocking rate of 15 smolt m3 and 85% survival is estimated to produce 30
  • 31. 300 tons of fish. In order to trap the particulate emissions from the fish unit 1350 tons (fresh weight) of mussel is required. The dissolved outflow from the fish unit as well as the mussel unit is estimated to support 3000 tons of seaweed. With the removal of the particulate emissions from the mussel unit, the filtered water emerging from the seaweed unit is rendered waste-free. The mass balance analysis of nitrogen, phosphorus and solids have been worked out (table 14-16). Table 14. Mass Balance Equation for Nitrogen ( Biological Waste Recovery) Fish Unit Sl.No Items Formula used Estimation . 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1 3 Feed Supply (kg) C=AxB 1000 4 Feed Wastage (%) D 10* 5 Feed Consumed (kg) E = C (100 – D)/100 900 6 Feed Undigested (%) F 20 7 Fecal Production (kg) G = E x F / 100 180 8 Nitrogen Content of Feed (%) H 7.5 9 Nitrogen Content of Feces (%) I 4 10 Nitrogen in Feed Supply (kg) J = C x H / 100 75 11 Nitrogen in Feed Waste (kg) K = C x D/100 x H/ 100 7.5 12 Nitrogen Ingested (kg) L = E x H / 100 67.5 13 Nitrogen Retained in Fish @ 3% B.W. (kg) M = A x 3 /100 30 14 Total Nitrogen Excreted (kg) N=L–M 37.5 15 Nitrogen in Feces (kg) O = G x I / 100 7.2 16 Nitrogen in Catabolic Product (kg) P=N–O 30.3 17 Total Nitrogen Load (kg) Q=K+O+P 45 18 Recovery of Nitrogen Load if any (kg) R 45 19 Net Nitrogen Load from fish unit on S = Q - R 0 environment (kg) Recovery of Nitrogen Load 20 Nitrogen Load - Particulate @13.5% (kg) Np1 = Q x 13.5 / 100 6 Supply to Mussel Unit 21 Nitrogen Load - Dissolved @86.5% (kg) Nd 1= Q x 86.5 / 100 39 Supply to Seaweed unit *Feed wastage @ 10% has been considered taking into account 1. lack of strict feeding regime and 2. greater feed availability considering closed environment of the unit 31
  • 32. Mussel Unit Sl.No Items Formula used Estimation . 1 Nitrogen Load From Fish Unit - Np1 6** Particulate (kg) 2 Nitrogen Transferred to Mussel biomass Nm = Np1 x 25 / 100 1.5 @25% of supply (kg) 3 Nitrogen in Feces @ 25% of supply Nf = Np1 x 25 / 100 1.5 4 Dissolved Nitrogen load - @50% (kg) Nd2 = Np1 x 50 / 100 3 5 Total Nitrogen load from Mussel Unit (kg) Tn = Nf + Nd2 4.5 6 Recovery of Nitrogen load from feces (kg) Using sediment trap 1.5 7 Recovery of Dissolved Nitrogen load (kg) Supply to Seaweed Unit 3 8 Total recovery of Nitrogen load from Item 6 + 7 4.5 Mussel Unit (kg) 9 Net Nitrogen Load from Mussel Unit on Item (5 – 8) 0 environment (kg) Sea Weed Unit Sl.No Items Formula used Estimation . 1 Dissolve 'N' Load of Fish Unit (kg) Nd1 39 2 Dissolve 'N' Load of Mussel Unit (kg) Nd2 3 3 Total Dissolved 'N' Load on Sea weed (kg) Nd = Nd1 + Nd2 42 4 Dissolve 'N' utilized by Seaweed Unit (kg) 42*** 5 Net Nitrogen Load from Sea Weed Unit Item ( 3 – 4 ) 0 on environment (kg) **Nitrogen Assimilation by Mussel unit 1. Particulate ‘N’ supply per ton fish = 6 kg 2. Total particulate ‘N’ supply from 300 ton fish = 1800 kg 3. Quantity of biomass that can be generated, considering 25% retention =.450 kg 4. Mussel’s pumping capacity with flow rate of 60 m3 min-1 @ 3times flow = 180 m3 min-1 5. Requirement of mussel considering flow rate of 2.5 l h-1 (25 gm size)= 4.32 m(approx. 4.5m) 6. Considering fresh weight (FW) of 25 gm, the requirement of mussel = 112.5 metric tons 7. With an exchange of mussel @ 112.5 mt. once a month, total annual requirement = 1350 mt. 8. Actual biomass produced on the basis of filtration requirement being higher than the nutrient etention, the total particulate ‘N’ load is expected to be bio-utilized ***Nitrogen Assimilation by Seaweed unit 1. Dissolved ‘N’ supply per ton of fish integrated with mussel = 42 kg 2. Total dissolved ‘N’ load from the entire unit / year = 12600 kg 3. Requirement of seaweed production (DW) in order to bind the dissolved ‘N’ load @ 4%(DW) = 315 mt 4. Fresh Weight of required seaweed production / year, considering 20% dry matter = 1575 mt 5. The per day production requirement of seaweed = 4.32 mt 6. The requirement of standing biomass @ 10% growth day-1= 43.2 mt 7. Considering 12 production units of 1000m3 capacity each, the standing stock m-3 = 3.6 kg 32
  • 33. Table 15. Mass Balance Equation for Phosphorus (Biological Waste Recovery)Fish Unit Sl.No Items Formula Estimation 1 Fish Production (kg) A 1000 2 Feed Conversion Ratio B 1 3 Feed Supply (kg) C=AxB 1000 4 Feed Waste (%) D 10 5 Feed Consumed (kg) E = C (100 – D) / 100 900 6 Feed Undigested (%) F 20 7 Fecal Production (kg) G = E x F / 100 180 8 Phosphorus Content of Feed (%) H 0.9 9 Phosphorus Content of Feces (%) I 1.5 10 Phosphorus in Feed Supply (kg) J = C x H / 100 9 11 Phosphorus in Feed Waste (kg) K = C x D/100 x H / 0.9 100 12 Phosphorus Ingested (kg) L = E x H / 100 8.1 13 Phosphorus Retained in Fish @ 0.4 % of M = A x 3 /100 4 B.W. (kg) 14 Total Phosphorus Excreted (kg) N=L–M 4.1 15 Phosphorus in Feces (kg) O = G x I / 100 2.7 16 Phosphorus in Catabolic Product (kg) P=N–O 1.4 17 Total Phosphorus Load (kg) Q=K+O+P 5 18 Recovery of Phosphorus Load if any (kg) R 5 19 Net Phosphorus Load from fish unit on S = Q - R 0 environment (kg) Recovery of Phosphorus Load 20 Phosphorus Load - Particulate @70% (kg) Pp1 = Q x 70 / 100 3.5 - Supply to Mussel Unit 21 Phosphorus Load - Dissolved @30% (kg) - Pd 1= Q x 30 / 100 1.5 Supply to Seaweed unit Mussel Unit Sl.No Items Formula / Notation Estimation 1 Particulate Phosphorus Load - From Fish Pp1 3.5** Unit (kg) 2 Phosphorus Transferred to Mussel biomass Pm = Pp1 x 25 / 100 0.875 @ 25% of supply (kg) 3 Phosphorus in Feces @ 50% of supply(kg) Pf = Pp1 x 50 / 100 1.75 4 Dissolved Phosphorus load @25% (kg) Pd2 = Pp1 x 25 / 100 0.875 5 Total ‘P’ load from Mussel Unit (kg) Tp = Pf + Pd2 2.625 6 Recovery of ‘P’ load from feces (kg) Using sediment trap 1.75 7 Recovery of Dissolved ‘P’ load (kg) Supply to Seaweed Unit 0.875 8 Total recovery of ‘P’ load from Mussel Item 6 + 7 2.625 Unit (kg) 9 Net Phosphorus Load from Mussel Unit Item (5 – 8) 0 on environment (kg) 33
  • 34. Sea Weed Unit Sl.No Items Formula / Notation Estimation . 1 Dissolve ‘P’ Load of Fish Unit Pd1 1.5 2 Dissolve ‘P’ Load of Mussel Unit Pd2 0.875 3 Total Dissolved 'P' Load on Seaweed (kg) Pd = Pd1 + Pd2 2.375 4 Dissolve 'P' utilized by Seaweed Unit (kg) 2.375*** 5 Net Phosphorus Load from Sea Weed Item ( 3 – 4 ) 0 Unit on environment (kg) **Phosphorus Assimilation by Mussel unit 1. Particulate ‘P’ supply per ton fish =3.5 kg 2. Total particulate ‘P’ supply from 300 ton fish = 1050 kg 3. Quantity of biomass that can be generated, considering 25% retention =.263 kg 4. Actual biomass produced on the basis of filtration requirement being higher than the nutrient retention, the total particulate ‘P’ load is expected to be bio-utilized ***Phosphorus Assimilation by Seaweed unit 1. Dissolved ‘P’ supply per ton of fish integrated with mussel production =2.375 kg 2. Total dissolved ‘P’ load from the entire unit / year = 713 kg 3. Requirement of seaweed production dry weight basis (DW) in order to bind the dissolved ‘P’ load @ 0.2%of (DW) = 356 mt 4. Fresh Weight of required seaweed production / year, considering 20% dry matter = 1780 mt 5. Since the above requirement is higher than the requirement for retention of dissolved ‘N’, hence the higher of the two requirements have been considered in designing the farming system 6. The per day production requirement of seaweed = 4.87 mt 7. The requirement of standing biomass @ 10% growth day-1= 48.7 mt 8. Considering 12 production units of 1000m3 capacity each, the standing stock m-3 = 4.0 kg 34
  • 35. Table 16. Mass Balance Equation for Total Solids (Biological Waste Recovery) Sl.No Items Formula Estimation . Outflow from Fish Unit 1 Particulate waste from fish unit A = Np1+ Pp1 9.5 supplied to mussel unit (kg) 2 Recovery of particulate waste from fish R1 9.5 unit by mussel unit 3 Net particulate waste from Fish unit S1 = A- R1 0 Outflow from Mussel Unit 1 Particulate waste from fish unit A 9.5 supplied to mussel unit 2 Transfer of nutrient to mussel unit as B = Nm + Pm 2.375 Biomass 3 Dissolved nutrient released from the C = Nd2 + Pd2 3.875 mussel unit 4 Solid waste from the Unit (Gross) Sg = A- (B + C) 3.25 5 Recovery of Solid Waste from Mussel R2 3.25^ unit using sediment trap 6 Solid waste from the Mussel Unit (Net) S2 = Sg – R2 0 Outflow from Seaweed Unit 1 Solid waste S3 = S1 + S2 0 Total Solid (SS) Load 1 Total Solid (SS) Load SS = S1 + S2 + S3 0 As the suspended solids from the fish unit is totally utilized by the mussel unit and the solid waste from the mussel unit is recovered using sediment trap hence the resultant suspended solid waste from the system is nil. Following integrated fish-mussel-seaweed farming the expected nutrient load on the environment in terms of ‘N’, ‘P’ and ‘SS’ could be theoretically reduced to zero thereby rendering it a clean technology (Fig.17). Commercialization of the concept holds great promise in terms of increased holding capacity of marine sites and sustainability of salmon farming. Production Potential Assessment Comparative assessment of production potentials using alternate technologies has been attempted. These technologies offer varying scope for reduction in nutrient loading and waste recovery as evident from the results presented in the previous section and summarized in table 17&18. Production potentials of Norwegian coastal zone as assessed under the LENKA system (Ibrekk, 1993) has been used as the benchmark. Average fish farm’s standard production of 25 kg /m3 (300 tons of fish produced per 12000 m3, requiring sea area of 2 km2 ) is the bench mark under consideration. Using the above production program with a feed conversion ratio of 1.5, annual loading from an average farm has been estimated to be 3 tons total phosphorus, 27 tons 35
  • 36. total nitrogen and approximately 150 tons of organic matter (Ibrekk, 1993). It is this reference nutrient emission level within which the production potentials of the alternate technologies have been evaluated (table 19). Table 17. Mass Balance Estimate for Nitrogen (1 tonne fish production) Item System1 System2 System3 System4 System5 Feeding Conventional Srtict feeding Srtict feeding Conventional Conventional Feeding regime regime with with mechanical biological waste waste recovery recovery Feed Conventional Improved feed HND feed Improved Improved feed feed feed Feed Wastage(%) 20 5 5 4 10 FCR 1.5 1 0.83 1 1 N' Content of feed 8 7.5 7.2 7.5 7.5 (%) Fish Production kg 1000 1000 1000 1000 1000 Feed used(Kg) 1500 1000 830 1000 1000 Feed waste (kg) 300 50 41.5 40 100 Feed consumed 1200 950 788.5 960 900 % undigested feed 25 20 18 20 20 Fecal Production* 300 190 142 192 180 N' supplied in feed 120 75 59.76 75 75 N' in feed waste 24 3.75 2.99 3 7.5 N' ingested 96 71.25 56.77 72 67.5 N' retained in Fish 30 30 30 30 30 N' excreted (Total) 66 41.25 26.77 42 37.5 N' in feaces 12 7.6 5.68 7.68 7.2 N' excreted as 54 33.65 21.09 34.32 30.3 catabolic product Total 'N' load 90 45 29.76 45 45 Recovery of 'N' load 0 0 0 9 45 N' load on 90 45 29.76 36 0 environment Assumptions: 1. Waste output in system5 is based on the fish unit and the recovery on the basis of total system, the component wise details already discussed 2. Loss of feed under strict feeding regime is 5% 3. Loss of feed in lift up system is based on assumption of initial loss of 20% followed by a recovery of 80% 4. Feed utilization in system5 is assumed considering 1. lack of feeding control on one hand and 2. better availability of feed on account of closed nature of the bag on the other 5. Recovery of 'N' in lift up is based on assumption that there would be 80% recovery of particulate ‘N’, which forms 25% of total ‘N’ load 6. Total Recovery of 'N' from system5 is based on assumption of integrated farming 36
  • 37. Table 18. Mass Balance Estimate for Phosphorus (1 ton fish production) Item System1 System2 System3 System4 System5 Feeding Conventional Srtict feeding Srtict feeding Conventional Conventional Feeding regime regime with with mechanical biological waste waste recovery recovery Feed Conventional Grower feed HND feed Grower feed Grower feed feed Feed Wastage(%) 20 5 5 4 10 FCR 1.5 1 0.83 1 1 P' Content of feed (%) 1 0.9 0.9 0.9 0.9 Fish Production kg 1000 1000 1000 1000 1000 Feed used(Kg) 1500 1000 830 1000 1000 Feed waste (kg) 300 50 41.5 40 100 Feed consumed 1200 950 788.5 960 900 % undigested feed 25 20 18 20 20 Fecal Production* 300 190 142 192 180 P' supplied in feed 15 9 7.47 9 9 P' in feed waste 3 0.45 0.37 0.36 0.9 P' ingested 12 8.55 7.1 8.64 8.1 P' retained in Fish 4 4 4 4 4 P' excreted (Total) 8 4.55 3.1 4.64 4.1 P' in feaces 4.5 2.85 2.13 2.88 2.7 P' excreted as catabolic 3.5 1.7 0.97 1.76 1.4 product Total 'P' load 11 5 3.47 5 5 Recovery of 'P' load 0 0 0 3 5 P' load on 11 5 3.47 2 0 environment Assumptions: 1. Waste output in system5 is based on the fish unit and the recovery on the basis of total system, the component wise details already discussed 2. Loss of feed under strict feeding regime is 5% 3. Loss of feed in lift up system is based on assumption of initial loss of 20% followed by a recovery of 80% 4. Feed utilization in system5 is assumed considering 1. lack of feeding control on one hand and 2. better availability of feed on account of closed nature of the bag on the other. 5. Recovery of 'P' in lift up is based on assumption that there would be 80% recovery of particulate ‘P’, which forms 75% of total ‘P’ load 6. Total Recovery of 'P' from system5 is based on removal by mussels & seaweed 37
  • 38. Based on the reference nutrient levels, the permissible limits from a farm with a production volume of 12000 m3 operating in a marine area of 2 km2 has been set at 180 tons (TS), 27 tons (N) and 3 tons (P). The level of total solids have been upwardly revised to accommodate the minimum potential criteria when applied to the traditional farming practice, which is type of farming that provides the back drop for ‘LENKA’ system of planning. The approximation involved in setting the limit as regard this parameter (Ibrekk et.al. 1993) has been availed to revise the limit. Table 19. Impact of Nutrient Load on Production Potentials/Holding Capacity Cage system Nutrient load (kg/ton) of fish Fish production (t) considering Holding Rank permissible nutrient loading capacity in a marine area of 2 sq. km under (Lowest of ‘LENKA’ planning system column 5, 6 & 7) Total Total 'N' Total 'P' Total solids Total 'N' Total 'P' In terms of In terms solids Fish yield of yield (tons) capacity 1 2 3 4 5 6 7 8 9 Permissible limit (kg) 180000* 27000 3000 Traditional Farming 600 90 10# 300 300 300 300 V Efficient feed with 240 45 5 750 600 600 600 IV strict feeding regime lift up collector 43 36 2 4186 750 1500 750 III HND feed with strict 184 30 3.47 978 900 864 864 II feeding regime Integrated fish- 0 0 0 unlimited unlimited unlimited unlimited I mussel-seaweed system * The level of total solids has been upwardly revised from the level of 150 ton to 180 tons taking in to account the minimum production potential of 300 tons set for the Norwegian marine sites using feed with FCR of 1.5 and the approximation involved in setting of this parameter. # The actual value is 11kg/tonne, rounded off to meet the minimum production norm. Transforming the nutrient loadings into fish production potential has been attempted for all the five farming systems (Table 19). As evident from the results, the minimum production is expected from the traditional farming involving production potential of 300 tons. The production potential could be enhanced to 600 tons using the farming system2 involving strict feeding regime and improved feed with FCR of 1.0. Total ‘N’ and ‘P’ being the limiting factors for this system. Using the lift-up system the level could be further enhanced to 750 tons, the limiting factor being the total ‘N’ load. The greater part of the nutrient load being in dissolved state, the lift up system was not effective in reducing the nitrogen load on environment. The system using HND diet provides a production potential of 864 tons i.e. 2.88 times the original target set under ‘LENKA’ system. Using the integrated farming system, the theoretical production level may be unlimited since the pollution level is ‘zero’. However this may not be practically feasible considering physical limitation of space. In the absence of any prescribed spacing norm for this type of farming an assessment has been made based on the assumptions (Table 20). According to this assessment considering horizontal space utilization (50% of available space), it may be possible to produce 30000 tons of fish in a marine area of 2 km2. Thus the expected production may be 100 times the original target set under ‘LENKA’ system. 38
  • 39. Table 20. Potential of Integrated Farming System based on Physical Space Consideration Sr. No. Assumptions Assessment 1 Area occupied by a fish unit 200m2 2 Area occupied by 12 fish units 2400 m2 3 Area occupied by 12 mussel units 2400 m2 4 Area occupied by 12 seaweed units 4800 m2 5 Total area 9600 m2(say 10000 m2 ) 6 Considering space between units (100%) 20000 m2 7 Marine area under consideration (2 k m2) 2000000 m2 8 No of units of the cage systems in the given area (that 100 can be accommodated physically) 9 Production potential of single unit of the cage system 300 tons 10 Production potential of 100 units 30000 tons 11 Increase in potential over original capacity 100 times Economics of Cage Farming The cost of production of salmon was worked out following the Norwegian case studies on Atlantic salmon (Bjdrndal 1990) and information collected during field study conducted in connection with the present project work. The comparative economics of the farming systems under consideration was studied using discounted cash flow technique as developed by the Economic Development Institute, International Bank for Reconstruction and Development (Gittinger 1981). As far as possible current prices have been gathered for carrying out economic analysis of the farming systems. However, the assessment is handicapped owing to limited access to the industry related information and cost details. Despite efforts it was not possible to get the current rates pertaining some of the investment components and hence there is dependence on the above case study for assessment of the production costs. Wherever possible cost have been updated based on current information. Efforts to collect the actual cost of the lift- up system and the closed bag system did not bear any fruit and hence indirect assessment has been made using personal judgment and references in published work. The inaccuracy in this regard was unavoidable in order to preserve the basic tenet of the project which aims at comparative assessment of the production cost / profitability and not at providing a guideline for investment. Besides, importance of the study lies in introducing the concept of economics in such planning and not providing the ultimate answer. The monetary values are expressed in Norwegian krone (NOK). The basic configuration and investment components of systems 1-4 are similar and all the farming systems under consideration are floating units comprising float, sea-pen system, moorings, feeding equipment with silo, generator, safety equipments, house, boats and miscellaneous equipments. The investment costs have been considered for units of 12000 m3 . The construction of these farms have been considered as turn-key installations. For the system4 (Lift-up system), additional cost on account of the collection structure below the pens have been considered. 39
  • 40. The farm production plan and estimated operating costs are based on the following assumptions: Item System1 System2 System3 System4 System5 3 3 3 3 3 Cage volume 12000m 12000m 12000m 12000m 6000m Stocking rate of 7.5 10 10 10 15 smolt/ m3 Smolt Price 9 9 9 9 9 (kr. / smolt) Duration of 24 24 24 24 24 rearing (months) Mortality 15 15 15 15 15 Av. Wt./ fish (kg) 4 3.7 3.7 3.7 4 Production in MT 300 370 370 370 300 Type of Feed Dry pelleted Improved feed HND diet Improved feed Improved feed FCR 1.5 1.0 0.83 1.0 1.0 Feed price 8.0 8.25 8.5 8.25 8.25 (kr./kg) Feeding principle Feeding to Strict feeding Strict feeding Feeding to Feeding to satiation regime regime satiation satiation Feed Waste 20% 5% 5% 4% 10%*** Fish Insurance 0.35 0.35 0.35 0.35 0.35 (kr./kg) nd nd nd nd nd Harvesting 2 yr.-25% 2 yr.-25% 2 yr.-25% 2 yr.-25% 2 yr.-25% rd rd rd rd rd 3 yr.-75% 3 yr.-75% 3 yr.-75% 3 yr.-75% 3 yr.-75% Processing Hired Hired Hired Hired Hired facility Packaging Hired Hired Hired Hired Hired facilities System1= Traditional farming system with conventional feed (FCR: 1.5) & no feeding control System2= Farming System with improved feed (FCR: 1.0) & strict feeding regime System3= Farming System with HND feed (FCR: 0.83) & strict feeding regime System4= Farming System with Lift up feed system System5= Integrated farming involving fish, mussel & sea weed Depreciation has been assessed on the following assumptions: Sl.No. Items (life of asset) Rate of Depreciation / Interest (%) 1 Interest on Investment/Working capital 7 2 Nets (4 years) 25 3 Feeding equipments (10 years) 10 4 Other investments ( 10 years) 10 Project Cost & Cash-Flow Analysis Taking account of the investment cost and the operating cost the project cost has been arrived at (table 21) . The cash flow analysis has been done taking into account the i. Capital cost in year1, ii. Replacement cost for the depreciated items viz. nets iii. Operating cost : 50% during year1 and 100% from year2 onward and iv. Income @ 25% during 2nd year and @ 100% from 3rd year onward (Table 22-26). 40
  • 41. Table 21. Project Cost of Cage Farming Systems (Amount in NOK) Item Traditional Improved 1 HND diet Lift up Integrated Investment cost Float 825000 825000 825000 825000 125000 House 270000 270000 270000 270000 270000 Cages 1300000 1300000 1300000 1300000 650000 Gangway 100000 100000 100000 100000 0 Crane & winches 50000 50000 50000 50000 50000 Moorings 300000 300000 300000 300000 300000 Feeding System 300000 500000 500000 300000 300000 Nets 500000 500000 500000 750000 0 Safety equipments 180000 180000 180000 180000 180000 Generator & equipments 100000 100000 100000 100000 100000 Boat 175000 175000 175000 175000 175000 Transport/Installation charges 200000 200000 200000 250000 150000 S. total (Investment cost) 4300000 4500000 4500000 4600000 2300000 Interest on Investment cost @4.5% 193500 202500 202500 207000 103500 Depreciation on nets@25% 125000 125000 125000 187500 0 Depreciation on feeding equipment@10% 30000 50000 50000 30000 30000 Depreciation on others@10% 350000 350000 350000 355000 200000 Depreciation on Investment cost 505000 525000 525000 572500 230000 S. total (Interest & Depreciation) 698500 727500 727500 779500 333500 Operating cost Variable Smolts@ NOK 8/smolt 720000 960000 960000 960000 720000 Feed@ NOK 7-7.5/kg 3150000 2682500 2303250 2682500 2175000 Insurance (fish) @ 0.35 NOK/kg 105000 129500 129500 129500 105000 Wages (workers) @ 180000/man 540000 540000 540000 540000 540000 S.total (variable cost) 4515000 4312000 3932750 4312000 3540000 Interest on working capital @ 4.5% 203175 194040 176973.75 194040 159300 Fixed Wages manager 200000 200000 200000 200000 200000 Administration 100000 100000 100000 100000 100000 Electricity 150000 150000 150000 150000 150000 Insurance (Facilities) 43000 45000 45000 46000 23000 Maintenance 215000 225000 225000 230000 115000 Travel 150000 150000 150000 150000 150000 Miscellaneous 100000 100000 100000 100000 100000 S. total (Fixed cost) 958000 970000 970000 976000 838000 S. total Operating cost 5473000 5282000 4902750 5288000 4378000 Total Project cost 9773000 9782000 9402750 9888000 6678000 Production (kg) 300000 370000 370000 370000 300000 Income @ NOK 27.5/KG 8250000 10175000 10175000 10175000 8250000 IRR 19.41 38.67 43.86 38.74 48.45 BCR 1.05 1.32 1.42 1.32 1.41 Production cost 6374675 6203540 5807224 6261540 4870800 Production in kg 300000 370000 370000 370000 300000 Production cost/kg (NOK) 21 17 16 17 16 Packing & Delivery @ NOK2/kg 600000 740000 740000 740000 600000 Operating cost + sale cost 6073000 6022000 5642750 6028000 4978000 Landed cost 23 19 18 19 18 41
  • 42. Cash Flow Analysis Table 22. Technology 1 - Traditional farming Year 1 2 3 4 5 6 7 8 9 10 Particulars Investment Cost 4300000 0 0 0 500000 0 0 500000 0 Operating cost +Sales cost 3036500 6073000 6073000 6073000 6073000 6073000 6073000 6073000 6073000 6073000 Total Cost 7336500 6073000 6073000 6073000 6573000 6073000 6073000 6073000 6573000 6073000 Income 0 2062500 8250000 8250000 8250000 8250000 8250000 8250000 8250000 8250000 Net Benefit -7336500 -4010500 2177000 2177000 1677000 2177000 2177000 2177000 1677000 2177000 IRR 7.78% PWC 31968397 PWB 29552289 BCR 0.924 :1.00 NPW -2416107.91 (+) Table 23. Technology 2 - Improved (With efficient feed/ feeding system) Year 1 2 3 4 5 6 7 8 9 10 Particulars Investment Cost 4500000 0 0 0 500000 0 0 500000 0 Operating cost+Sales cost 3011000 6022000 6022000 6022000 6022000 6022000 6022000 6022000 6022000 6022000 Total Cost 7511000 6022000 6022000 6022000 6522000 6022000 6022000 6022000 6522000 6022000 Income 0 2543750 10175000 10175000 10175000 10175000 10175000 10175000 10175000 10175000 Net Benefit -7511000 -3478250 4153000 4153000 3653000 4153000 4153000 4153000 3653000 4153000 IRR 26.40% PWC 31908526 PWB 36447823 BCR 1.142 :1.00 NPW 4539296.47 (+) Table 24. Technology 3 - Improved (With HND feed/efficient feeding system) Year 1 2 3 4 5 6 7 8 9 10 Particulars Investment Cost 4500000 0 0 0 500000 0 0 500000 0 Operating cost+Sales cost 2821375 5642750 5642750 5642750 5642750 5642750 5642750 5642750 5642750 5642750 Total Cost 7321375 5642750 5642750 5642750 6142750 5642750 5642750 5642750 6142750 5642750 Income 0 2543750 10175000 10175000 10175000 10175000 10175000 10175000 10175000 10175000 Net Benefit -7321375 -3099000 4532250 4532250 4032250 4532250 4532250 4532250 4032250 4532250 IRR 30.86% PWC 30170050 PWB 36447823 BCR 1.208 :1.00 NPW 6277773.17 (+) 42
  • 43. Table 25. Technology 4 - Lift up system with efficient feed Year 1 2 3 4 5 6 7 8 9 10 Particulars Investment Cost 4600000 0 0 0 750000 0 0 750000 0 Operating cost+Sales cost 3014000 6028000 6028000 6028000 6028000 6028000 6028000 6028000 6028000 6028000 Total Cost 7614000 6028000 6028000 6028000 6778000 6028000 6028000 6028000 6778000 6028000 Income 0 2543750 10175000 10175000 10175000 10175000 10175000 10175000 10175000 10175000 Net Benefit -7614000 -3484250 4147000 4147000 3397000 4147000 4147000 4147000 3397000 4147000 IRR 25.61% PWC 32218347 PWB 36447823 BCR 1.131 :1.00 NPW 4229476.25 (+) Table 26. Technology 5 - Clean Technology ( Closed bag integrated farming system) Year 1 2 3 4 5 6 7 8 9 10 Particulars Investment Cost 2300000 0 0 0 0 300000 0 0 0 0 Operating cost+Sales cost 2489000 4978000 4978000 4978000 4978000 4978000 4978000 4978000 4978000 4978000 Total Cost 4789000 4978000 4978000 4978000 4978000 5278000 4978000 4978000 4978000 4978000 Income 0 2062500 8250000 8250000 8250000 8250000 8250000 8250000 8250000 8250000 Net Benefit -4789000 -2915500 3272000 3272000 3272000 2972000 3272000 3272000 3272000 3272000 IRR 31.17% PWC 24948780 PWB 29552289 BCR 1.185 :1.00 NPW 4603508.51 (+) The results indicate that the traditional system of farming is not remunerative with IRR (=7.78) and the production cost at NOK 21. The total cost of the produce inclusive of expenses on sales would be NOK 23. The sale price being NOK 27.5, the margin of profit would be under considerable pressure if there is any increase in cost of feed or fall in price of fish. The best return was encountered with the integrated farming system (IRR = 31.17) followed by the system using HND diet (IRR = 30.86). The return for the System2 (using strict feeding regime and feed with FCR of 1) and from the system 4 (using lift-up system) were more or less similar IRR being 26.4 and 25.16 respectively. The cost of production for both the systems is NOK 17, marginally higher compared to the System 3 (using HND feed) and System 5 (using integrated farming), wherein the cost of production is NOK 16. Thus from the point of view of return on investment and the production cost, System 3 and System 5 would perform better compared to the other systems. The return from the integrated system could be even higher if the benefits from sale of produce from the mussel and seaweed units are taken into account, which in the present case has not been done on account of lack of adequate information. The cost of production has been arrived at after taking into account operating cost, interest & depreciation on investment cost, interest on working capital (table 27). The Cost of production of all except the traditional system compares well with the Norwegian Industry average for the year1997 estimated at NOK 16.75 (KPMG 1999). The margin for all the systems excepting System1 is comfortable, which may be revealed by the sensitivity analysis.
  • 44. Table 27 Profit margin per unit volume of sales Item Traditional Improved HND Diet Lift up System Integrated Cost of Production/kg 21 17 16 17 16 Selling Expense 2 2 2 2 2 Total Cost 23 19 18 19 18 Sale price 27.5 27.5 27.5 27.5 27.5 Margin 4.5 8.5 9.5 8.5 9.5 It is evident from the results (table 28) that the production cost structure of the farming systems under the present investigation closely match that of the Norwegian fish industry. All the major items excepting interest structure are in agreement. In the present analysis, depreciation has also been added to the interest component. It is not very clear if this component has been considered in the production cost estimate of the Directorate (KPMG 1999). As may be evident, the most important variable is the feed cost, which could determine the profitability of the operation. Thus a rise in feed cost or wastage on account of this input could alter profit margin considerably. Hence a prudent operator needs to keep an eye on feed consumption keeping the cost under check. Though smolt price is the next biggest component yet it is not a matter of concern at the moment since the price in this regard has been falling steadily in recent time on account of over production. Table 28. Production cost Structures of the Five Farming Systems vis-à-vis the Norwegian Industry Average (Items expressed as % of Production cost) Norwegian Item Traditional Improved 1 Improved2 Lift up Clean Average # Cost of smolt 11 16 16 15 15 16 Cost of Feed 49 43 40 43 45 50 Insurance 2 2 2 2 2 2 Labor 12 12 13 12 15 10 Other operating cost 12 12 13 12 13 16 Total Interest+Depreciation 14 15 16 16 10 6* # Source Directorate of Fisheries (Published by KPMG management consulting * It is not clear if Depreciation is taken into account A sensitivity analysis was conducted to study the effect of rise in feed cost (10%), fall in price of salmon (10%) and a combination of both factors on the profitability of the farming systems. Both rise in feed cost and falling price of Norwegian salmon are possible threats to the industry. Table 29. Sensitivity Analysis: Impact of rising Feed Cost and fall in Salmon price on IRR Item Traditional Improved HND Diet Lift up System Integrated IRR based on present 7.78 26.4 30.86 25.61 31.17 costs & sale price Rise in Feed Cost (10%) 3.28 23.29 28.14 22.51 27.59 Fall in Sale price (10%) 3.11 17.44 22.08 16.58 21.19 Rise in Feed Cost (10%) + -9.00 14.09 19.24 13.25 17.45 Fall in Sale price (10%)
  • 45. Analysis of the risk perception on both counts show considerable fall in profitability. The greater impact was associated with fall in sale price of salmon (Table 28). The traditional farming was rendered non-viable on both occasions. The combination of the factors may be disastrous for traditional farming (IRR = -9). Although the combined impact of both the risk factors on the remaining systems is considerable yet, the profitability of the systems would enable them to withstand the tastes of economic viability (IRR ranging between 13.25 – 19.24). Further it may be observed that although the return is more in the integrated system over the one using HND diet (maintaining strict feeding regime), the impact of all the three risks factors discussed here are more pronounced in case of the former system .
  • 46. Discussions Mass Balance Analysis Three different feeds have been selected for assessment of nutrient loading using the chosen technologies under the present study. In the traditional farming system (System1) use of conventional feed with FCR value of 1.5 (‘N’= 8%; ‘P’ = 1%) has been considered. Though present day feed are much lower in ‘N’ & ‘P’ content however the assessment of ‘Area Capacity’ under ‘LENKA’ is based on this kind of feed and hence for the shake of comparison it was necessary to include this as control. The improved feed with FCR value of 1.0 (‘N’= 7.5% ; ‘P’ = 0.9%) has been considered for the remaining technologies excepting one (Sustem3) in which HND diet has been considered. FCR for the HND diet is taken as 0.83 (‘N’= 7.2% ; ‘P’ = 0.9%). The aim is to compare the least efficient feed with quality feed and the nutrient dense feed in terms of their nutrient loadings. The quality feed has also been considered as the basis for mass balance modeling of the two technologies concerning i.waste recovery (Lift-up) and ii. nutrient recycling (Integrated farming). The results of the nutrient loadings analysis using the three types of feed under investigation have been revalidated using available information (Table 30). As it may appear, the mass balance assessments made under the present study are in close agreement with similar study undertaken( Enell et al 1991, Cho et al 1994). The difference between System1 & System1A is on account of ‘N’ content of the feed itself. Table30. Revalidation of Nutrient loading using the three feeds under study with available information (published) on such feed use (Quantity in kg/ton fish) Item System1 System1A System2 System2A System3 System3A Feed Convention Convention Improved Improved HND feed HND feed al feed al feed feed feed Feed Wastage(%) 20 NA 5 NA 5 NA FCR 1.5 1.5 1 1 0.83 0.83 % undigested feed 25 NA 20 NA 18 NA ‘N’ Supply in feed 120 108 75 NA 60 NA ‘N’ retained in fish 30 30 30 30 30 30 ‘N’ (Solid) 36 17 11 10 8.76 6 ‘N’ (Dissolved) 54 61 34 40 21 33 Total 'N' load 90 78 45 50 29.76 39 ‘P’ Supply in feed 15 13.5 9 9 9 8 ‘P’ retained in fish 4 4 4 4 4 4 ‘P’ (Solid) 7.5 7.3 3.3 4 2.5 3 ‘P’ (Dissolved) 3.5 2.2 1.7 2 0.97 1.5 Total 'P' load 11 9.5 5 6 3.47 4.5 Total Solids 600 NA 240 240 184 190 System1 Traditional Farming (Present study) System1A Traditional Farming (Enell & Ackefors 1991) System2 Efficient feed with strict feeding regime (Present study) System2A Efficient feed with strict feeding regime (Cho et al 1994) System3 HND feed with strict feeding regime (Present study) System3A HND feed with strict feeding regime (Cho et al 1994)
  • 47. Similar revalidation in case of Lift-up Kombi system is handicapped owing to lack of published data on mass balance analysis involving the model. However the present analysis has been carried out within the framework of available information. The Lift-up Kombi system is known to collect upto 100% surplus feed, sized 6 mm and larger and nearly 70% of 4 mm particles (Ervik et al, 1994). It is stated (SFT 1993) that “ The surplus feed collector can also reduce the general impact of fish farms on their recipients. This is most important for marginal recipients, since the life span of these locations are increased significantly. The negative environmental feedback on fish farm in such environment will be diminished, - instead of resulting in poor health conditions and high needs of antibacterials. The higher cost of the equipment are shown to be balanced by the benefits of automatic dead fish collection, increased growth, reduced feed conversion rates and lower mortality of the fish.” The results of the present analysis indicate 80% reduction in total solids compared to System2 which provides the basic production program using the improved feed (FCR=1). The results of the mass balance analysis of the integrated farming system, shows a total recovery of nutrient from the system combining biological removal (involving particulates by mussels and dissolved nutrients by seaweeds) with mechanical removal of sediments from mussel unit. The results are in close conformity with the findings of Bodvin et al (1996). According to Bodvin et. al.(1996) production of 300 metric tons of salmon is expected to generate 15 tons of nitrogen and 2.4 tons of phosphate using, a standard high energy dry feed with a feed conversion factor of 1. Of the above, the 13 metric tonnes of ‘N’ and 0.7 metric tons of ‘P’ are dissolved. Outlet water is transferred from the salmon units to enclosed mussel units. A standing stock of 112.5 metric tons of mussels (WW) is necessary to filtrate 60 m3 min–1 . If all particles are filtered through the mussel, 25% of the nitrogen is accumulated as increased biomass. 25-30% is released as faeces and 45-50% as dissolved matter. Particles are removed by a sedimentation trap. Outlet water from the 12 mussel filter units, containing 13.9 metric tons of dissolved N (0.9 metric tons from the mussels), is transferred to closed units with seaweeds. A standing stock of 45 metric tons (FW) of seaweed is theoretically needed to bind up all dissolved N from the salmon and mussel production. The above assumptions are in agreement with the results of mass balance analysis of the present study. The mass balance analysis of the farming systems (System1 to System3) indicates a progressive fall in nutrient load on environment both in terms of ‘N’ and ‘P’ levels starting from System1 to System3, which can be attributed to the improvement in feed quality and feeding practices followed (table 31). The results obtained using low protein diet (System2) and high energy nutrient dense diet (HND) used in System3 are on expected line as discussed by several authors (Cho et al 1994,Ackefors 1997 and Stigebrandt 1999). Similar trend as in the case of ‘N’ and ‘P’ is witnessed in respect of the Total solid loadings (TS). The falling trend in total solid level is associated with lesser feed wastage following detection of un-eaten feed through hydro-acoustic equipment and computer aided control of the feeding regime in System2 and System3. Though the type of feed used in System4 and System5 are same as in System2, the nutrient loads in terms of ‘P’, ‘N’ and ‘TS’ in these systems are different from System2 on account of recovery of nutrient in both the systems. The recovery in System4 being mechanical described earlier, is effective against particulate matter. As a result there is substantial recovery of phosphorus emission which appears more in particulate form (75%) than Nitrogen (25%). Thus the fall in respect of ‘P’ is more appreciable than ‘N’. There is substantial fall in the level of total solids (82%). The situation is considerably different for System5 wherein the recovery of both solid as well as dissolved nutrient is total. This system being integrated with mussel and seaweed units, the solid waste from the fish unit is taken
  • 48. care by the mussels which are particle feeders. The solid wastes from the mussel units are removed using sediment traps in mussel units. The dissolved nutrients from both the fish as well as mussel units are fully recovered using seaweed as the biological filter. Table31.Comparative account of nutrient loading following the five farming systems Item System1 System2 System3 System4 System5 Feed Conventional Improved feed HND feed Improved Improved feed feed feed Total 'N' load 90 45 29.76 45 45 Recovery of 'N' load 0 0 0 9 45 N' load on 90 45 29.76 36 0 environment Total 'P' load 11 5 3.47 5 5 Recovery of 'P' load 0 0 0 3 5 P' load on 11 5 3.47 2 0 environment Total Solids (kg/ton 600 240 184 43 0 fish) The above observations follow the established trends in fish nutrition programme and consequently the principles governing reduction in nutrient loading based on improvement in feed quality. Feed is the source of nutrient supply to the farming system. In order to be least polluting, the system should be able to assimilate the supplied nutrients to its maximum ability. This is possible if the loss on account of uneaten feed is minimum, digestibility of the feed as well as the bio-availability of the nutrients is high. The loss on account of uneaten feed is a function of the feed quality, feed distribution and fish behaviour. The feed quality refers to its water stability characteristics, sinking speed, palatability, colouration whereas feed distribution is in turn a function of human understanding of fish physiology and feeding behaviour. Feeding techniques are mostly based on attainment of satiation level as reflected in the behaviour of the fish. However automatic feeding based on ‘release of predetermined amount of feed at regular intervals’ is not receptive to such behavioural changes in feeding thus resulting in unutilised fish feed. Such feed wastage could be as high as 40% (Thrope et al. 1990). In the present study using automatic feeder under normal feeding control (System1) feed loss has been considered to be 20%. The fish model described as part of MOM (Monitoring-Ongrowing fish farms-Modelling) has considered feed loss on this account to the extent of 25-26% (Stigebrandt 1999). Using the feeding systems based on feeding behaviour of the fish that reflects its satiation level (Hand feeing, Demand feeding), one may be relying on the hypothalamus control of the fish, the physiological control being stimulated by the stretch receptors in the fore-end of the gut and possibly by the blood sugar level. Such natural physiological controls have evolved to deal with the natural food encountered in the wild. However, the nutrient content of the artificial feed being of much higher order, the supply of nutrient may be much higher than required, resulting in poor FCR (Beveridge 1996). The hand feeding and the use of demand feeder which operates on the above concept, could be wasteful on this count. However the wastage in this case may not be in the form of feed loss but in the shape of higher FCR. Feed wastage in fact could be as low as (1.4%) of total feed supply (Thrope et al. 1990). However hand feeding/demand feeding is not included in the present study since the emphasis is now on maintaining strict feeding regime (working on detection of uneaten feed and feeding behaviour as a feed back control on computerised feeding programme). The automatic feeding control systems used in conjunction with hydro- acoustic feed detection is likely to have a check on the total food supply through its pre-set computer controlled feeding program as well as its monitoring system scanning the cage volume for detection of unutilised feed particles. This enables minimising feed loss as well as FCR. The feed loss could be to the extent of 4% of total nutrient supply (Baird et al. 1996).
  • 49. In the present study feed loss under strict feeding regime has been considered @ 5% involving System2 & 3. Similar wastage has been considered for this type of feeding involving lake trout (Cho et al. 1994). After ensuring minimum loss on account of uneaten feed, the task before a fish farm manager would be to ensure maximum retention of nutrient, which could be attained through proper selection of highly digestible ingredients, selection of ingredients with low P/N ratio, meeting optimum protein / energy ratio (DP/DE), increase the density of energy and protein keeping P/E constant. Formulation of such low protein high lipid diets are required to prevent use of protein as the energy source resulting in loss of body weight of fish. Presence of high level of dietary digestible lipid would ensure use of protein only for anabolic process resulting in increased body weight (Cho et al 1994,Ackefors 1997 and Stigebrandt 1999). In selection of the three type of feeds in the present study, the above parameters have been taken into account as reflected in their ‘N’ & ‘P’ content as well as P/N ratio. Similar trend may be observed as regards digestibility of the feeds used, increased bio-availability as reflected in FCR values and BOD (total solids) wastes of the different feed used in the present study (Table 31 & 32). Table 32. The fate of Nutrient Supplied in feed following the five farming systems Item System1 System2 System3 System4 System5 Feed Conventional Improved HND feed Improved Improved feed feed feed feed Feed Wastage(%) 20 5 5 4 10 FCR 1.5 1 0.83 1 1 % undigested feed 25 20 18 20 20 N' Content of feed (%) 8 7.5 7.2 7.5 7.5 N' retained in Fish (%) 25 40 50 40 40 N' excreted (Dissolved) (%) 45 45 35 46 40 N' excreted(Solid) (%) 30 15 15 14 20 Total 'N' load (%) 75 60 50 60 60 Recovery of 'N' load (%) 0 0 0 12 60 N' load on environment (%) 75 60 50 48 0 P' Content of feed (%) 1 0.9 0.9 0.9 0.9 P' retained in Fish (%) 27 44 53 44 44 P' excreted (Dissolved) (%) 23 19 13 20 16 P' excreted(Solid) (%) 50 37 34 36 40 Total 'P' load (%) 73 56 47 56 56 Recovery of 'P' load (%) 0 0 0 33 56 P' load on environment (%) 73 56 47 23 0 Assumptions: 1. Loss of feed under strict feeding regime is 5% 2. Loss of feed in lift up system is based on assumption of initial loss of 20% followed by a recovery of 80% 3. Feed utilization in system5 is assumed considering 1. lack of feeding control on one hand and 2. better availability of feed on account of closed nature of the bag on the other 4. Recovery of 'N' in lift up is based on assumption that there would be 80% recovery of particulate ‘N’, which forms 25% of total ‘N’ load 5. Total Recovery of 'N' from system5 is based on assumption of integrated farming Thus feed coefficient and the content of phosphorus (‘P’) and nitrogen (‘N’) in the feed are two important factors to consider while assessing environmental impact of aquaculture (Ackefors, 1997). Taking cue from such recent developments in feed formulations in lowering nutrient discharge, an effort was made to compare the different types of feed in terms of their nutrient loading characteristics as reflected in System1,2&3. Further, effort was
  • 50. made to superimpose impact of feeding efficiency (System 1,2&3) and nutrient recovery mechanisms (Systems 4&5) on the performance of improved feed to study the relative nutrient loadings. While the ‘N’ loading has steadily fallen from the level of 75% in System1 to 50% in System3 on account of better feed quality as well as feeding technique, the ‘P’ loading has fallen from 73% in System1 to 47% in System3 (Table32). In quantitative terms, the above fall in nitrogen loading per ton of fish is from 90 kg to 30kg while that of phosphorus is from 11 kg to 3.47 kg (Table 31). The difference in loading in terms of both ‘N’ and ‘P’ between System2 and System3 is a reflection of feed quality, the feeding technique remaining same. Further fall in nutrient loading in System 4&5 as compared to System2 is a reflection of the impact of nutrient recovery vis-à-vis better feeding mechanism, feed quality remaining constant. A trade-off between efficient feeding mechanism and efficient feed recovery was necessary since they are mutually exclusive. If there is no feed loss there is no need for recovery. Although there may still be need for recovery of undigested matter yet, the same was not considered for the present study since analyzing the impact would have been difficult. Observations made by Ackefors (1997) on time-series data on discharge of nutrients and organic materials as a function of reduction in feed conversion ratio and content of nitrogen and phosphorous in commercial salmon feed is relevant in the above context. He indicated that during the past two decades while the feed coefficient has decreased from 2.3 to less than 1.3, the nitrogen content in the feed has decreased from 7.8% to 6.8% and that of phosphorous from 1.7% to 1.1% (Enell et al 1990 and Ackefors 1997). This has resulted in lowering of discharge of nutrient per tonne of produced fish. In case of nitrogen it has decreased from 129 kg to 53 kg and for phosphorus from 31 kg to 9.5 kg (Ackefors, 1997). Production Potential Assessment Comparative assessment of production potentials using alternate technologies is a new dimension in coastal zone planning. The present process is not sensitive to differential nutrient loading associated with technological innovations, which could be used as a planning tool. The Norwegian licensing norm in respect of marine fish farming may be cited as an example. As already discussed the farming operation has been restricted to 300 tons / unit of 12000m3 in a marine area of 2 km2 based on the permissible nutrient loading linked to holding capacity and area capacity assessment. However, the same area using the reduced nutrient loading characteristics of the improved technologies as discussed earlier could be put to much higher production either by allowing greater production volume from the same area or by allowing more units in the same marine area. Using the reference nutrient emission level as defined in the Norwegian coastal zone management plan, it is possible to produce 600 tons using the farming system2, 750 tons using lift-up system, 864 tons using System3 and approximately 30000 tons using the clean technology as against the benchmark of 300 tons. Considering vertical use of the water area, the potentials of the closed bag system integrating fish, mussel and seaweed farming could be many times over. Thus the planning process needs to be integrated with technological developments and the production potential evaluated in time and space. The concept of ‘holding capacity’ was developed to denote maximum aquaculture production attainable in a water body without eliciting an unacceptably high degree of environmental change. The validity of the concept would depend on the flexibility of the planning process to address such changes with rapidly evolving technology. From the ecological stand point, sustainable development is based on the concept of ‘carrying capacity’ and as reflected in the definition (Chapter 1 of this document), the
  • 51. objective is sustenance of maximum population indefinitely in a given habitat without permanently impairing the productivity of the ecosystem(s) upon which that population is dependent. The above objective would be best served if the planning approach addresses the issue pertaining enhancement of holding capacity in relation to technological advancements as depicted in the present study. ‘Modelling-On growing fish farms-Monitoring’ (MOM), which is a management system used to adjust the local environmental impact of marine fish farms to the holding capacity of the sites is a step in this direction (Ervik et al.1997). The concept is based on integrating the elements of environmental impact assessment, monitoring of impact and environmental quality standards into one system. Following this it may be possible to revise the holding capacity assessment based on feed back from monitoring studies that in turn would set the quality standards. However, the revision would be limited to existing nutrient loadings following cage farming practices in vogue. Hence the planning based on the above would be reactive. A pro-active planning process would look for alternate production plans for the same marine area using available technology with different waste reduction and mitigation efficiency. It has been indicated that reduction in feed wastage by 30% would increase the potential of aquaculture by 6-8 % and in areas of high level of aquaculture activity such as Hordaland, the effect would be even greater (Ibrekk 1993). Thus the present study may be considered to be a step in proactive planning which could capture the dynamics of changing technology in environmental context. Such dynamics of planning could be utilized as incentives for farms adopting cleaner technology (based on verifiable records) to produce more through higher productivity permits. All technologies with lower emission may not be feasible from practical application point of view such as the lift-up system or on grounds of economics of operation discussed subsequently. Such evaluation needs to be integrated to the planning process. There could be some spin-off benefits out of such planning process wherein incentive is linked to better waste management by way of enhanced in-house R&D addressing these problems. With increasing competition for sites and water resource in the coastal zone between aquaculture and other users viz. agriculture, shipping, tourism, salt manufacture, harbours, aquapark etc. (Chua et al.1992) it may be necessary to realize higher production volume from a given area necessitating such technological evaluation. Economics of Salmon Farming It is evident from the study that the traditional system of farming is not remunerative with IRR being 7.78 and the cost of landing being NOK 23 as against sale price of NOK 27.5. The sensitivity analysis shows the IRR falling below the bank rate. With the combined fall in sale price (10%) and rise in feed cost (10%) the IRR turned negative. The best return was encountered with the integrated farming system (IRR = 31.17) followed by the system using HND diet (IRR = 30.86).The return for the System2 (using strict feeding regime and feed with FCR of 1) and for the system 4 (using lift-up system) were more or less similar, IRR being 26.4 and 25.16 respectively. The cost of production for both the systems are NOK 17, marginally higher compared to the System 3 (using HND feed) and System 5 (using integrated farming), wherein the cost of production is NOK 16. Thus from the point of view of return on investment and the production cost, System 3 and System 5 would perform better compared to the other systems. The return from the integrated system could be even higher if the benefits from sale of produce from the mussel and seaweed units are taken into account. The Cost of production of all except the traditional system compares well with the Norwegian
  • 52. Industry average for the year1997 estimated at NOK 16.75 (KPMG 1999). Thus based on economic viability if one was to select the technology, the choice in the first place would be between System5 and System3. Since system 5 is not yet commercialized, obviously the choice would be System3. The most important variable is the feed cost, which could determine the profitability of the operation. Thus a rise in feed cost or wastage on account of this input could alter profit margin considerably. Hence from the economic stand point technology using efficient feed and feed management systems may be need to be encouraged. Since fall in salmon price is a major threat to the industry, hence lowering cost of production becomes another important concern for the industry. Though smolt price is the next biggest component yet it is not a matter of concern at the moment since the price in this regard has been falling steadily in recent time on account of over production. To remain competitive in the global market there is downward pressure on sale price discussed subsequently. However both EU market and American market have imposed anti-dumping restrictions on Norwegian salmon. The greater impact on account of risk was associated with fall in sale price of salmon over rise in feed cost. Although the combination of the two risk factors proved disastrous for traditional farming yet, the remaining systems retained viability (IRR 13.25 – 19.24). The Norwegian interest rate being 4.5% and the inflation rate being 3.5% such returns may render the operation attractive. Further it may be observed that although the return is more in the integrated system over the one using HND diet (maintaining strict feeding regime), the impact of all the three risks factors discussed here are more pronounced on the former. This may be due to the fact that the wastage of feed is more in the integrated system compared to the other system, although the nutrient loading is nil considering its biological recovery by the mussels. Thus any future commercial application of the system would need to address this problem through suitable incorporation of feeding management. This would highlight the role of economic analysis in improvement of technology and planning. The present trend in the industry (fig.18) would suggest that the salmon farming in Norway has to work under an environment of increasing feed cost, likely to go upward mainly on account of dependence on high quality fish meal; fall in smolt price due to overcapacity and possible fall in sale price of fish due to trade related embargo. The interest rate and inflation rate being quite low farther fall in interest rate may not be a major factor contributing to the bottom line. Working within this framework, ‘feed’ would appear to be the single major constraint and its increasing role in production cost over the years would suggest that the technology relying on efficient feed with low FCR and effective feed management would at the end succeed in meeting the market requirements dictated by lower production cost and higher return. Since the feed producers are facing high raw material prices and the profit margin of the feed industry is very slender (2.7%) a likely hike in feed cost possibly can not be avoided. The rise in fish price (20%) and fish oil (60%) over the past year is a concern for the industry with no solution in sight (KPMG 1999). The natural resource base in respect of the above raw material is not expanding and hence sustainability of this resource hungry industry would depend on new technological development in the industry part replacing fish meal as an ingredient. Research in this regard is afoot but may take time. Till such time the alternate feed ingredient is found, the industry would have to manage with farming systems consuming minimum feed with low FCR values, equipped with efficient feed distribution system. Thus the industry information is in tune with the present assessment and hence corroborates the findings in this regard.
  • 53. Operating within the above framework of feed related issues, one would require to address three other economics related issues which are crucial for the survival of the industry. These issues are: 1.economies of scale, 2.cost of production and 3.environmental cost. It is stated that the profitability of operation of salmon farming is under strain owing to market related issues. The processing industry today can realise NOK 46 per kg of salmon fillet. Going by the prevailing raw material cost of NOK 27.5, the fillet yield of 70% and other direct costs, the cost of production works out to be NOK 47.30 yielding a gross profit of NOK –1.30 (KPMG 1999). The units are able to operate only through long term contracts with fish farmers for supply of required volume of supply. This in turn puts pressure on the supplier side to produce at a cost which is affordable and in required volume. The companies which have been able perform better are the ones with two permits. The acquisition of permits at market price require large capital spending. Under the present situation allowing more production from the existing permit using environment friendly techniques as reported under the present study could be sound proposition and may allow the required economy of scale for the farming units. The cost of production beside feed would depend on other costs (Table 27). Though these parameters are under constant surveillance of the industry and being regulated, there may be scope for cutting down the cost through secondary production as in the case of integrated fish-mussel-seaweed production system. Though futuristic at this stage, such ideas need to be explored in order to meet the challenges before the industry. As discussed in the beginning the cost of pollution is going to be an increasing concern globally more so with the developed economies where public concern over environmental issues is very strong. Paying for such costs could put further pressure on the profit margins. The problem could be better addressed by use of low polluting / self cleaning systems such as the integrated farming. The system beside being self cleaning is also self generating as regard scarce high quality protein ingredients for fish food is concerned. Mussel meat and sea weed beside being additional out put from the system generating higher profit, could be important from the resource generation point of view. Thus salmon farming, an otherwise resource hungry production system as it is known to be, could turn into a resource generating system – the ultimate goal in terms of sustainable development may be a reality.
  • 54. Conclusions The results of the nutrient loadings analysis suggests progressively decreasing loading starting from System1 to System5 in terms of phosphorus and total solids. In case of nitrogen the overall trend remains the same with the exception of System4 using Lift-up system wherein the ‘N’ load is more than the load in System3. Using this information it has been possible to reassess the ‘Holding Capacity’ of the representative marine sites in terms of nutrient loading using the five different farming systems. Whereas following the existing norms as delimited under the ‘LENKA’ system of planning, a farm with 12000 m3 operating in a 2 km2 sea area is permitted 300 ton fish production, the possible production following the farming systems under consideration could be 300, 600, 864, 750 and 3000 tons for systems1,2,3,4 and 5 respectively adopting the same bench mark in terms of nutrient loadings. The benchmark under reference is regulating Norwegian fish farming for nearly a decade while the emission levels has undergone sea change on account of development of new technology primarily related to feed quality and efficient feeding system. Thus a case is made out for sensitizing the planning process to environmental enabling potentials of the technological innovations. As par the need of the hour beside being cost sensitive, the industry needs scale of economy for the production units. It is known that the better profitable companies are the one having more than one permit. The cost of acquisition of such permit at market price is prohibitive. Revalidation of the production norm taking cue from the above transformation in production technology, the level of production could at least be doubled thus preempting need for the second permit. Such revalidation is being suggested not as an one time affair but as an ongoing process linked to technological enabling factors. The planning process so developed beside permitting higher productivity through holding capacity enhancement (in terms of production) would provide incentive for generation of newer technology thereby promoting the very purpose behind its regulatory function. As on date the bench mark for production could perhaps be set on the basis of nutrient emission level under System2 following efficient feeding management and use of quality feed (FCR:1.0). The medium term goal could be adoption of System3 using HND diet and following strict feeding regime. This system has the potential of raising the holding capacity to three times its present level. A slightly long term goal could be set based on the outcome of the technologies under trial. Going by the outcome of the mass balance study, assessment of the production potential and economics of production, the System5 adopting integrated fish-mussel-seaweed production (Clean technology) seems to be holding great promises in terms of not merely enhancing holding capacity but fulfilling such sustainability criteria as ‘zero emission’, ‘resource generation’ and ‘integrated production’. In terms of economics, the production could prove to be low cost if the integrated production cycle is taken into consideration. As such the system compares well with the best of available technologies in terms of rate of return and production cost. The additional production dimensions could result in better return. The above observations are in agreement with established trends in fish feed management strategy as well as environmental regulations. ‘Modelling-On growing fish farms- Monitoring’ (MOM), which is a management system used to adjust the local environmental impact of marine fish farms to the holding capacity of the sites is a step in this direction (Ervik et al.1997). It has been indicated that reduction in feed wastage by 30% would increase the potential of aquaculture by 6-8 % and in areas of high level of aquaculture
  • 55. activity such as Hordaland, the effect would be even greater (Ibrekk 1993). The present exercise is an extension of this idea which merits further investigation. The suggested framework for development of the sector could be a small step in realizing the goals set out by The FAO while defining ‘sustainable development’. These goals as applicable to aquaculture sector would ensure management and conservation of natural resource base and the orientation of technological and institutional changes in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. It would conserves land, water, plant and animal genetic resources, beside being environmentally non-degrading, technically appropriate, economically viable and socially acceptable
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  • 59. Figure 1. Method of Calculating Available Gross Capacity (LENKA)
  • 60. Figure 2a: Conventional Floating Steel Cage Farm Figure 2b. Traditional Steel Cages with Catwalks
  • 61. Figure 3a. Polar Circle Cages with Automated Feeding System Figure 3b. Centralized Feeding System in use for Steel Cages
  • 62. Figure 4. Feeder boat delivering food to the fish via a water cannon
  • 63. Figure5. Aquasmart PS1 Feed Monitoring System for Hand feeding Figure 6. Aquasmart PS2 Feeding Control System for Feed Cannons
  • 64. Figure7a. Aquasmart AQ1 Adaptive Fish Feeding System Controlling Auto Feeder Transponder Doppler Video Online Monitoring Figure 7b. Akva Sensor System for Hydroacoustic Feed Detection
  • 65. Compressor Filtration Unit Outlet Compressed Air Wide Meshed Net Cage Air Lift Pipe Fine Meshed Net Wate r Funnel flow Wastes Hose Extra Load Figure 8. Schematic Sketch of the Lift – Up Kombi Waste Feed Collector
  • 66. Total food Supply Feed In gested Fs = Fp x FCR Fi = Fs – Uf Total ‘N’ in Feed Total ‘N’ in Feed In gested N1 = A x N /100 N3 = Fi x N / 100 N = % ‘N’ in Feed ‘N’ Ret ain ed in Fish N4 = Fp x A / 10 0 Excretion A = ‘N’ % in Fis h Nitrogen in Urine + Gills N6 = N3 – ( N4 +N5) Fish Prod uct i on = F P Fecal M atter Fm = Fi x Udf Uneaten Food Udf = % Undigested Feed Uf = Fs x W astage % (W ) ‘N’ in Fecal M atter Total ‘N’ in Uneaten Food N5 = Fm x B / 100 N2 = Uf x N / 100 B = ‘N’ % in Feces Figure 10: Flow Chart of nutrient wastes (Nitrogen)
  • 67. Total food Supply Feed Ingested Fs = Fp x FCR Fi = Fs – Uf Total ‘P’ in Feed Total ‘P’ in Feed Ingested P1 = A x P /100 P3 = Fi x P / 100 P = % ‘P’ in Feed ‘P’ Retained in Fish P4 = Fp x A’/ 100 A’ = ‘P’% in Fish Excretion Phosphorus P6 = P3 – ( P4 +P5) Fish Production = FP Fecal Matter Fm = Fi x Udf Uneaten Food Udf = % Undigested Feed Uf = Fs x Wastage % (W) ‘P’ in Fecal Matter Total ‘P’ in Uneaten Food P5 = Fm x B’ / 100 P2 = Uf x P / 100 B’ = ‘P’ % in Feces Figure11: Flow Chart of nutrient wastes (Phosphorus)
  • 68. Total food Supply Feed Ingested Fs = Fp x FCR Fi = Fs – Uf Feed di ges ted & Retaine d i n F ish Fd = Fi x D / 100 Fish Prod uct i on = F P Uneaten Food Fecal M atter Uf = Fs x Wastage % (W) Fm = Fi - Fd Suspended Solids SS = Uf + Fm Figure 12. Flow Chart of Suspended Solid wastes
  • 69. Gross Feed Gross Feed Waste Supply ‘N’ = 60 kg ‘N’ = 15 kg ‘P’ = 7.2 kg ‘P’ = 1.8 kg Feed Recovery ‘N’ = 12 kg ‘P’ = 1.44 kg Net Feed Waste ‘N’ = 3 kg ‘P’ = 0.36 kg Net Environnmental Gross Loading on Recovery of Loading Lift-up Collector particulates ‘N’ = 45 kg ‘N’ = 9 kg ‘N’ = 36 kg ‘P’ = 5 kg ‘P’ = 3 kg ‘P’ = 2kg
  • 70. Figure 18 : Development in Norwegian production cost structure (1986-1996) Development in production cost structure 60 50 Smolt % Production cost Feed 40 Insurance 30 Labour Other op. 20 cost Interest 10 0 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 Year Reconstructed from :The Value chain in the fish farming industry, KPMG 1999