This document summarizes an environmental study of a marine cage fish farm in Matanchén Bay, Mexico. Water and sediment samples were collected monthly from stations near the fish cages, upstream as controls, and downstream as potential impact areas. Physicochemical parameters of the water and sediment were analyzed, including nutrients, organic matter, and granulometry. Results showed temporal variations in nutrients in the water column and sediment composition. Nitrates generally had the highest concentrations in potential impact stations. Overall, parameters tended to increase in concentration in potential impact and control stations, indicating effects from the fish farm and seasonal runoff.
Physico-chemical parameters and macrobenthic invertebrates of the intertidal ...Angelo Mark Walag
Physico-chemical parameters and macrobenthic invertebrates of the intertidal zone of Gusa, Cagayan de Oro City, Philippines were assessed from March to May 2014. Water temperature, pH, salinity, dissolved oxygen, biological oxygen demand, and type of substrate were determined in the study were within the normal range. A modified transect-quadrat method was used in an approximately 14,000 m2 of study area. Seven hundred twenty seven individuals belonging to 15 species were found in the area. These organisms belong to four phyla namely: Mollusca, Arthropoda, Echinodermata, and Annelida. The three most abundant organisms found were Coenobita clypeatus, Ophiothrix longipeda, and Cypraea poraria with relative abundance of 73.86%, 4.13% and 3.71% respectively. Most of the macrobenthic fauna identified exhibited a clumped pattern of distribution, while the rest are randomly distributed. The species diversity of the area is 1.19 which is very low compared to reports from related studies.
Production performance of whiteleg shrimp Litopenaeus vannamei at different s...UniversitasGadjahMada
This study examined the effects of different stocking densities on production performance of whiteleg shrimp (Litopenaeus vannamei) cultured in sandy ponds with plastic mulch. Shrimp were stocked at densities of 100, 200, and 300 shrimp/m2 and reared for 75 days. Results showed that final weight, daily growth rate, and survival rate decreased with increasing density, while feed conversion ratio and biomass production increased. The lowest density of 100 shrimp/m2 resulted in the highest final weight of 12.93g, growth rate of 0.1526g/day, and survival rate of 96.54%, but the lowest biomass production of 14.99kg/m2. Water
Status of Phytoplankton Community of Kisumu Bay, Winam Gulf, Lake Victoria, K...theijes
Lake Victoria has undergone remarkable and diverse ecological perturbations which are as a result of physical, chemical and biological processes, together with human activities that take place in the watershed area and within the lake itself. The most observed effects include increases in phytoplankton biomass and frequent algal blooms. In this study species composition, abundance, spatial and temporal distribution of phytoplankton as well as total phytoplankton biomass of Kisumu Bay, (Winam Gulf), Lake Victoria, Kenya was studied for six months in the wake of climate change. Sampling was done every two weeks using a Van Dorn Water sampler to take water samples and algal cells were counted under an inverted microscope with the help of a Sedge-Wick Rafter Cell in order to determine density. Phytoplankton biomass indicated by chlorophyll-content was determined through cold extraction in acetone and subsequent quantification by spectrophotometry. Physicochemical parameters were measured in situ using respective meters, while plant nutrient levels were determined by spectrophotometric methods following standard methods of APHA 1985 and Gems (1992) Handbook. ANOVA test was used to determine any temporal and spatial variability in the biological factors. Regression and Pearson’s correlation analyses were done to establish relationships between these factors. LSD test was done to determine means which were significantly different. The results indicated that a total of 36 genera of algae belonging to Cyanophyta, Bacillariophyta, Chlorophyta and Pyrrophyta were present, with dominance of the classes in terms of number of species being in that order. Chroococcus species was the most abundant and its density was significantly different from all the others. Most algal species were more or less homogenously distributed in the bay (p=1.0000) and over the study period (p=1.0000), but their densities varied significantly between different species (p<0.0001). From these results, it can be concluded that the phytoplankton community within the bay is becoming very dynamic and could possibly portray the status in the whole lake. Diatoms are becoming increasingly dominant. There is continual increasing trend in physico-chemical factors. The information obtained from this work contributes to the understanding of ecological changes in the bay in response to climate change and variability and thus the threat to biodiversity. This information is therefore important for ecological and management purposes of the lake and understanding effects of climate change on ecosystem structure, functioning and productivity.
2011 nutrient enrichment caused by marine cageearambulm3
This document summarizes a study that evaluated the influence of marine cage aquaculture on coral reef communities in turbid waters near Penghu Islands, Taiwan. The study found that levels of ammonium, nitrite, and chlorophyll a released from fish cages distinguished the area closest to the cages (Impact Zone 1) from areas further away (Impact Zone 2 and the reference zone). Coral communities closest to the cages were dominated by stress-tolerant coral species while areas further away supported more diverse coral morphologies. The results suggest that nutrient enrichment from the fish cages is deteriorating suitable habitat for coral reef organisms at the study site.
Environmental conditions and zooplankton community structure in five ponds in...Innspub Net
The degradation of surface water quality in Cameroon is linked to the absence of a functional waste management strategy. For such a strategy to be efficient, a general understanding of aquatic ecosystems will be of importance, these management strategies are particularly lacking in the eastern part of the country. To better understand and appreciate the ecosystems in the town of Bertoua, five ponds where chosen for the physicochemical and zooplankton communities analysis. Sampling on these ponds was conducted from March 2016 to April 2017 on a monthly basis. Samples for physicochemical analysis were collected at 20cm below water surface at the middle of each pond and measured were done following the recommendations of Rodier and Alpha. Biological samples were collected by filtering 50 liters of water through a 64µm mesh opening sieve. Identification was done using standard methods and identification keys. One-way ANOVA analysis was conducted to assess the potential differences between the different ponds base monthly observations. Although they are all hypereutrophic, with regard to the values of the physicochemical parameters, the five ponds showed no significant difference between them but, the structure of the zooplankton community remains very diverse. 118 zooplankton species have been identified in the five ponds. The distribution of zooplankton in these hydrosystems was mainly governed by the presence of organic matter. This study sheds light on the status and biological diversity of ponds in eastern Cameroon, data on which to rely to develop management strategies.
4.Influence of stocking density on production and water quality of a photo-he...earambulm3
- The study examined the effect of stocking density on shrimp production in a photo-heterotrophic intensive system using circular lined ponds with minimal water replacement.
- Five stocking densities were tested (100, 300, 500, 700, 900 shrimp/m3) and water quality, growth, and survival were measured over 98 days.
- Results showed water quality was maintained at all densities but higher densities had increased TAN, nitrate, and phosphorus levels. Growth and survival decreased at densities over 300 shrimp/m3. The 500 shrimp/m3 density achieved the highest biomass and production.
Productivity of phytoplankton using different organic fertilizers in the glas...AbdullaAlAsif1
The experiment intended to estimate the productivity using different organic fertilizer and to identify the species of phytoplankton in the aquarium tanks. The study was conducted in the laboratory Phytoplankton samples for culture were collected from fisheries experimental pond by using conical-shaped monofilament nylon net (phytoplankton net). Three treatment such as cow dung (T₁), chicken manure (T₂) and control (T₃) were designed. Each treatment had two replications. In case of T₁ and T₂, 10 g of fertilizer was used in each aquarium tank. Sampling of phytoplankton for counting and identification was done every week and 1 litre of water sample was taken from each tank. Phytoplankton sample for identification were preserved by Lugol's solution. Three physicochemical parameters namely water temperature, dissolved oxygen (DO) and pH were measured in every sampling week during the study period. Water quality parameters of the aquarium tank varied with the variation of sampling week. There was no significant difference between water temperature, pH and DO in case of three treatment. The mean water temperature, pH and DO were 21.85±1.95 °C, 8.38±0.23 and 5.55±0.58 mg/l, respectively. The abundance of phytoplankton in T₁, T₂ and T₃ were 25-65, 25-105 and 6-20 individual/l, respectively. The phytoplankton abundance were influenced by different organic fertilizer and noticed higher in number by using chicken manure. Irregular relationship between phytoplankton abundance and water temperature was found. Phytoplankton showed positive relationship with DO. In this study 15 species of phytoplankton were identified under four groups namely Chlorophyta, Cyanophyta, Bacillariophyta and Euglenophyta. Chlorophyta (52%) was the dominant group in the aquarium. The findings of the present study will help to improve the management strategies of water quality, for estimating the productivity of phytoplankton and for the best use of organic fertilizer especially chicken manure.
Standard water quality requirements and management strategies for fish farmin...eSAT Journals
A study on standard water quality requirements and management strategies suitable for fish farming is presented. The water quality criteria studied based on physical, chemical and biological properties of water include temperature, turbidity, total suspended solids (TSS), total dissolved solid (TDS), nitrate- nitrogen, pH, biochemical oxygen demand (BOD) and total hardness. Water samples from Otamiri River in Imo state, Nigeria, were analyzed based on the afore-mentioned criteria to assess its suitability as a source of water for fish farming. The results of the analysis compared with international standards revealed that the river temperature of 26.90C, nitrate-nitrogen value of 0.015 mg/l and total suspended solids of 18.60 mg/l fall within the acceptable range for fish farming. However, the pH of 5.82, total hardness of 5.8 mg/l, total dissolved solids of 13.60 mg/l and biochemical oxygen demand of 0.6 mg/l all differed slightly from the standard recommended values. This study will aid fish farmers on the necessary treatment needed to effectively use water from this source for fish farming.
Keywords: Water quality criteria, Otamiri River, biochemical oxygen demand, total suspended and total dissolved solids.
Physico-chemical parameters and macrobenthic invertebrates of the intertidal ...Angelo Mark Walag
Physico-chemical parameters and macrobenthic invertebrates of the intertidal zone of Gusa, Cagayan de Oro City, Philippines were assessed from March to May 2014. Water temperature, pH, salinity, dissolved oxygen, biological oxygen demand, and type of substrate were determined in the study were within the normal range. A modified transect-quadrat method was used in an approximately 14,000 m2 of study area. Seven hundred twenty seven individuals belonging to 15 species were found in the area. These organisms belong to four phyla namely: Mollusca, Arthropoda, Echinodermata, and Annelida. The three most abundant organisms found were Coenobita clypeatus, Ophiothrix longipeda, and Cypraea poraria with relative abundance of 73.86%, 4.13% and 3.71% respectively. Most of the macrobenthic fauna identified exhibited a clumped pattern of distribution, while the rest are randomly distributed. The species diversity of the area is 1.19 which is very low compared to reports from related studies.
Production performance of whiteleg shrimp Litopenaeus vannamei at different s...UniversitasGadjahMada
This study examined the effects of different stocking densities on production performance of whiteleg shrimp (Litopenaeus vannamei) cultured in sandy ponds with plastic mulch. Shrimp were stocked at densities of 100, 200, and 300 shrimp/m2 and reared for 75 days. Results showed that final weight, daily growth rate, and survival rate decreased with increasing density, while feed conversion ratio and biomass production increased. The lowest density of 100 shrimp/m2 resulted in the highest final weight of 12.93g, growth rate of 0.1526g/day, and survival rate of 96.54%, but the lowest biomass production of 14.99kg/m2. Water
Status of Phytoplankton Community of Kisumu Bay, Winam Gulf, Lake Victoria, K...theijes
Lake Victoria has undergone remarkable and diverse ecological perturbations which are as a result of physical, chemical and biological processes, together with human activities that take place in the watershed area and within the lake itself. The most observed effects include increases in phytoplankton biomass and frequent algal blooms. In this study species composition, abundance, spatial and temporal distribution of phytoplankton as well as total phytoplankton biomass of Kisumu Bay, (Winam Gulf), Lake Victoria, Kenya was studied for six months in the wake of climate change. Sampling was done every two weeks using a Van Dorn Water sampler to take water samples and algal cells were counted under an inverted microscope with the help of a Sedge-Wick Rafter Cell in order to determine density. Phytoplankton biomass indicated by chlorophyll-content was determined through cold extraction in acetone and subsequent quantification by spectrophotometry. Physicochemical parameters were measured in situ using respective meters, while plant nutrient levels were determined by spectrophotometric methods following standard methods of APHA 1985 and Gems (1992) Handbook. ANOVA test was used to determine any temporal and spatial variability in the biological factors. Regression and Pearson’s correlation analyses were done to establish relationships between these factors. LSD test was done to determine means which were significantly different. The results indicated that a total of 36 genera of algae belonging to Cyanophyta, Bacillariophyta, Chlorophyta and Pyrrophyta were present, with dominance of the classes in terms of number of species being in that order. Chroococcus species was the most abundant and its density was significantly different from all the others. Most algal species were more or less homogenously distributed in the bay (p=1.0000) and over the study period (p=1.0000), but their densities varied significantly between different species (p<0.0001). From these results, it can be concluded that the phytoplankton community within the bay is becoming very dynamic and could possibly portray the status in the whole lake. Diatoms are becoming increasingly dominant. There is continual increasing trend in physico-chemical factors. The information obtained from this work contributes to the understanding of ecological changes in the bay in response to climate change and variability and thus the threat to biodiversity. This information is therefore important for ecological and management purposes of the lake and understanding effects of climate change on ecosystem structure, functioning and productivity.
2011 nutrient enrichment caused by marine cageearambulm3
This document summarizes a study that evaluated the influence of marine cage aquaculture on coral reef communities in turbid waters near Penghu Islands, Taiwan. The study found that levels of ammonium, nitrite, and chlorophyll a released from fish cages distinguished the area closest to the cages (Impact Zone 1) from areas further away (Impact Zone 2 and the reference zone). Coral communities closest to the cages were dominated by stress-tolerant coral species while areas further away supported more diverse coral morphologies. The results suggest that nutrient enrichment from the fish cages is deteriorating suitable habitat for coral reef organisms at the study site.
Environmental conditions and zooplankton community structure in five ponds in...Innspub Net
The degradation of surface water quality in Cameroon is linked to the absence of a functional waste management strategy. For such a strategy to be efficient, a general understanding of aquatic ecosystems will be of importance, these management strategies are particularly lacking in the eastern part of the country. To better understand and appreciate the ecosystems in the town of Bertoua, five ponds where chosen for the physicochemical and zooplankton communities analysis. Sampling on these ponds was conducted from March 2016 to April 2017 on a monthly basis. Samples for physicochemical analysis were collected at 20cm below water surface at the middle of each pond and measured were done following the recommendations of Rodier and Alpha. Biological samples were collected by filtering 50 liters of water through a 64µm mesh opening sieve. Identification was done using standard methods and identification keys. One-way ANOVA analysis was conducted to assess the potential differences between the different ponds base monthly observations. Although they are all hypereutrophic, with regard to the values of the physicochemical parameters, the five ponds showed no significant difference between them but, the structure of the zooplankton community remains very diverse. 118 zooplankton species have been identified in the five ponds. The distribution of zooplankton in these hydrosystems was mainly governed by the presence of organic matter. This study sheds light on the status and biological diversity of ponds in eastern Cameroon, data on which to rely to develop management strategies.
4.Influence of stocking density on production and water quality of a photo-he...earambulm3
- The study examined the effect of stocking density on shrimp production in a photo-heterotrophic intensive system using circular lined ponds with minimal water replacement.
- Five stocking densities were tested (100, 300, 500, 700, 900 shrimp/m3) and water quality, growth, and survival were measured over 98 days.
- Results showed water quality was maintained at all densities but higher densities had increased TAN, nitrate, and phosphorus levels. Growth and survival decreased at densities over 300 shrimp/m3. The 500 shrimp/m3 density achieved the highest biomass and production.
Productivity of phytoplankton using different organic fertilizers in the glas...AbdullaAlAsif1
The experiment intended to estimate the productivity using different organic fertilizer and to identify the species of phytoplankton in the aquarium tanks. The study was conducted in the laboratory Phytoplankton samples for culture were collected from fisheries experimental pond by using conical-shaped monofilament nylon net (phytoplankton net). Three treatment such as cow dung (T₁), chicken manure (T₂) and control (T₃) were designed. Each treatment had two replications. In case of T₁ and T₂, 10 g of fertilizer was used in each aquarium tank. Sampling of phytoplankton for counting and identification was done every week and 1 litre of water sample was taken from each tank. Phytoplankton sample for identification were preserved by Lugol's solution. Three physicochemical parameters namely water temperature, dissolved oxygen (DO) and pH were measured in every sampling week during the study period. Water quality parameters of the aquarium tank varied with the variation of sampling week. There was no significant difference between water temperature, pH and DO in case of three treatment. The mean water temperature, pH and DO were 21.85±1.95 °C, 8.38±0.23 and 5.55±0.58 mg/l, respectively. The abundance of phytoplankton in T₁, T₂ and T₃ were 25-65, 25-105 and 6-20 individual/l, respectively. The phytoplankton abundance were influenced by different organic fertilizer and noticed higher in number by using chicken manure. Irregular relationship between phytoplankton abundance and water temperature was found. Phytoplankton showed positive relationship with DO. In this study 15 species of phytoplankton were identified under four groups namely Chlorophyta, Cyanophyta, Bacillariophyta and Euglenophyta. Chlorophyta (52%) was the dominant group in the aquarium. The findings of the present study will help to improve the management strategies of water quality, for estimating the productivity of phytoplankton and for the best use of organic fertilizer especially chicken manure.
Standard water quality requirements and management strategies for fish farmin...eSAT Journals
A study on standard water quality requirements and management strategies suitable for fish farming is presented. The water quality criteria studied based on physical, chemical and biological properties of water include temperature, turbidity, total suspended solids (TSS), total dissolved solid (TDS), nitrate- nitrogen, pH, biochemical oxygen demand (BOD) and total hardness. Water samples from Otamiri River in Imo state, Nigeria, were analyzed based on the afore-mentioned criteria to assess its suitability as a source of water for fish farming. The results of the analysis compared with international standards revealed that the river temperature of 26.90C, nitrate-nitrogen value of 0.015 mg/l and total suspended solids of 18.60 mg/l fall within the acceptable range for fish farming. However, the pH of 5.82, total hardness of 5.8 mg/l, total dissolved solids of 13.60 mg/l and biochemical oxygen demand of 0.6 mg/l all differed slightly from the standard recommended values. This study will aid fish farmers on the necessary treatment needed to effectively use water from this source for fish farming.
Keywords: Water quality criteria, Otamiri River, biochemical oxygen demand, total suspended and total dissolved solids.
Coastal marine ecosystem scientific paper swissmitchick
The document summarizes a study assessing the macrobenthic flora and fauna in the intertidal area of Dalipuga Beach in Iligan City, Philippines. Two 1-square-meter quadrats were placed in the transect line to analyze species composition. Only one algae species (Phaeophyta) was found in the first quadrat, while the second quadrat contained both algae and seagrass. Water temperature was 26-27°C, soil temperature was 25-26°C, humidity was 26%, sediment was sand and gravel, and pH and salinity were normal. No macrobenthic fauna was found.
Evaluation of the oyster farming potential of the Cintra bay (southern Morocco)Origins publication
The bay of Cintra is a marine ecosystem located in the southern Moroccan Atlantic known for its
biological richness and therefore for its high fishery productivity. This bay was chosen as a new destination for the
development of aquaculture in the southern regions of Morocco. To highlight its potential in terms of oyster
farming, a first rearing trial of triploid cupped oysters (Crassostrea gigas) as well as parallel monitoring of the
phytoplankton population and ecological parameters were undertaken. The results obtained showed that the oysters
adapt well to the conditions of the new environment where mortality was negligible, or even absent after a month
of launching. In terms of biological performance, the growth of individuals is continuous during the annual cycle
and after eight months the weight could reach 30.5 g which is a minimum weight for marketing. The AFNOR and
Lawrence and Scott indices showed a good physiological state and a better commercial quality of the oysters. The
filling rate of these oysters, with an average weight of 39.7g when lifting, is very high according to the Lawrence and
Scott index (126.3) and the average AFNOR index (around 21.8) rank them in the “Special” category.
AQUATIC GENETIC RESOURCES AND CLIMATE CHANGE_CleanPatrick White
This document provides an overview of the importance of aquatic genetic resources in the context of climate change. It discusses how aquatic ecosystems and the organisms they support play a key role in global carbon and nutrient cycles. Aquatic genetic resources underpin global aquaculture and fisheries, which together provide about half of the world's food fish and are important for food security, nutrition, and livelihoods. Climate change poses challenges for these resources and the sectors that depend on them through impacts like warming, acidification, and changes to freshwater availability. The roles of aquatic genetic resources in adapting to and mitigating climate change impacts are discussed.
Stress of Environmental Pollution on Zooplanktons and theirComparative Studi...theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
2009 assessment effects of cage culture on nitrogenearambulm3
This document summarizes a study that investigated nitrogen and phosphorus dynamics in relation to fallowing periods for a fish cage farm located in a shallow lake in China. The study analyzed total nitrogen and total phosphorus levels in lake water and sediment during two fish rearing cycles from 2000-2001. Key findings include:
1) Nutrient levels increased more during the first rearing cycle than the second.
2) Impacts were greatest near the cages (underneath and at cage sides), with higher sedimentation of nitrogen and phosphorus observed at cage sides.
3) After 3 months of fallowing, water nutrient levels decreased significantly but sediment nutrient levels remained high, indicating recovery occurs during fallowing
An Investigation into how Climate Driven Oceanic Warming may effect the Filtr...Ciara Condit
This study investigated how ocean warming may affect the filtration rates of the blue mussel (Mytilus edulis). Individual mussels were exposed to four temperature treatments (7°C, 16°C, 20°C, and 25°C) and their filtration rates measured. Statistical analysis found filtration rates increased significantly with higher temperatures, with the greatest difference between 7°C and 25°C. While filtration may increase in a warmer climate, overall mussel productivity is likely to decrease due to other climate impacts such as ocean acidification and reduced food availability.
Stomach histological decay of milkfish, chanos chanos (forsskal, 1775)Alexander Decker
This document summarizes a study on the histological decay of the stomach in milkfish (Chanos chanos) reared in a traditional brackishwater pond in East Java, Indonesia. Several factors were found to contribute to deterioration of the stomach, including environmental stress from heavy metals in the water, high ammonia levels, a shift in the natural food composition to cyanobacteria, and infection by the Myxobolus parasite. Earlier harvest, higher mortality, and smaller fish size compared to normal indicated declining productivity of traditional milkfish aquaculture in the region in recent decades.
This project monitored changes in phytoplankton communities in a eutrophic Irish lake over a 6-month period to determine the lake's health. Phytoplankton assemblages followed distinct successional stages that correlated with changing water quality. These assemblages provided evidence that the lake remained near the mesotrophic/eutrophic border despite rehabilitation efforts. The study evaluated phytoplankton's sensitivity as biological indicators of ecological status under the Water Framework Directive.
1) The document evaluates the management effectiveness of the National Natural Park Rosario and San Bernardo Corals marine protected area in Colombia using biological, socioeconomic, and governance indicators.
2) Biological surveys found low coral cover and fish diversity/abundance both inside and outside the MPA, suggesting limited effectiveness of current management. The reefs also showed signs of degradation.
3) Socioeconomic and governance analyses revealed low incomes for local communities, few opportunities, weak governance, and overexploitation of resources inside the MPA. This reflected low adaptive capacity to comply with conservation rules.
The document summarizes the mission and science-based work of the National Park Service at the Cape Cod National Seashore. It discusses inventorying, monitoring, and research efforts across various natural systems to understand resources, track changes over time, and inform adaptive management. Examples of current and future studies are provided covering topics like salt marsh restoration, water quality, species populations, climate change impacts, and more. The work involves interdisciplinary teams of scientists, technicians, and ecologists.
Effect of water parameters on temporal distribution and abundance of zooplank...AbdullaAlAsif1
Seasonal abundance of zooplankton in relation to different physico-chemical conditions of Kaptai lake has been studied. A total of four major groups of zooplankton were identified from study area of Kaptai lake during three seasons observation at pre-monsoon, monsoon and Post-monsoon. These four groups were categorized into rotifers, copepods, cladocerans and others (fish larvae, shrimp larvae, insects, mosquito larvae etc.). The mean abundance of group rotifers, copepods, cladoceras and others were 103, 84.67, 38.33 and 41.83 ind. L-1 respectively. The highest group was rotifers in terms of abundance and composition where compositions were recorded 38 % at three season's observation. The lowest group was cladoceras in term of abundance and composition where compositions were recorded 14 %. The air temperature, water temperature, transparency, water pH, DO, BOD5, PO 4-P, NO 2-N, SiO 3-Si, TSS, TDS, Alkalinity ranged between 21 and 27.5C, 23.5 and 31.5C, 0.8 and 3 m, 7.1 and 7.5, 5.72 and 8.58 mg/l, 8.55 and 12.87 mg/l, 3.22 and 4.13 µg/l, 0.992 and 1.19 µg/l, 161.18 and 201.15 µg/l, 0.28 and 0.48 g/l, 0.18 and 0.68 g/l, 40 and 60 ppm, respectively. Margalef richness index (d), Pielou's evenness index (J'), Shannon-Wiener diversity index (H'), Simpson dominance index (λ) are analyzed by Primer V6 software to quantify the collected species. Through same software SIMPER, Cluster analysis also done to compare similarity between season.
The effects of different water quality parameters on zooplankton distribution...iosrjce
IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) multidisciplinary peer-reviewed Journal with reputable academics and experts as board member. IOSR-JESTFT is designed for the prompt publication of peer-reviewed articles in all areas of subject. The journal articles will be accessed freely online
Intact Oceans and Their Benefits, by Edward Lohnes, Conservation InternationalWILD Foundation
The document discusses several papers that illustrate the benefits of healthy oceans. It summarizes that intact oceans are crucial for life on Earth and provide many services like food and climate regulation. However, oceans face many threats from human activities. Studies show that marine protected areas can help restore ecosystems and biodiversity by limiting fishing and other extractive activities. Recent research also finds that dynamic protection approaches may further help increase fish biomass. Additionally, protecting blue carbon sinks can significantly offset carbon emissions and help mitigate climate change. Comprehensive ocean zoning is needed to manage cumulative human impacts on marine environments.
IRREVERSIBLE? Climate Change, Fisherfolks, and the Coastal Communitymeih
The document discusses the impacts of climate change on coastal communities and fisheries in the Philippines. It notes that the Philippines has extensive coastlines and coastal populations that are highly dependent on marine fisheries for food and livelihood. Climate change is expected to negatively impact coral reefs, fisheries, and coastal resources through rising sea levels, increased temperatures, and more extreme weather. This will threaten food security and biodiversity in the Philippines. The document also discusses observed shifts in species ranges and abundances due to ocean warming globally.
Qualitative and quantitative analysis of phytoplankton in culture pond of Noa...AbdullaAlAsif1
A study was conducted on qualitative and quantitative analysis of phytoplankton in cultured ponds of two fish farms of Noakhali district, Bangladesh from 15 September to 15 November 2012 to identify and estimate the abundance of phytoplankton in various culture ponds of two fish farms. Analyses of phytoplankton samples recorded a total of 4 classes phytoplankton viz.; Bacillariophyceae, Chlorophyceae, Cyanophyceae, Euglenophyceae. Out of 21 phytoplankton genera identified, 5 belong to Cyanophyceae, 7 to Chlorophyceae, 5 to Bacillariophyceae and 4 to Euglenophyceae. Among the identified genera, Euglena, Microcystis, Eurolena were found to be dominant genera. Total phytoplankton abundance was varied from 36×105 cells/L to 94.92×105 cells/L in the experimental ponds. Among all experimental ponds, Chlorophyceae was found dominant (44.4×105 cells/L). Second dominant group was Euglenophyceae (39.6×105 cells/L) observed in pond-1 of Bismillah Agro Production (BAP). Total phytoplankton densities were recorded 47.82×105cells/L and 51×105 cells/L in pond-1 and pond-2 of Subarna Agro Based Initiative (SABI) respectively. In BAP, total phytoplankton densities were recorded 94.92×105cells/L and 36×105 cells/L in pond-1 and pond-2 respectively. Management technique and water quality parameters were also studied during study period namely water temperature, conductivity, salinity, transparency, dissolve oxygen and pH. The present study reveals that phytoplankton species are variable among the culture ponds and their density is also variable. The information provides for more research to compare water quality and pond phytoplankton characteristics in earthen aquaculture systems with and without fish stocking. Further studies on the seasonal changes of water quality parameters and its effects on phytoplankton production in the fish ponds and all year extended monitoring is recommended in future studies.
The document summarizes a study that monitored water quality and benthic ecosystems around fish farms in Igoumenitsa Bay, Greece between 2011-2012. Water samples found increased nutrients like phosphorus near the fish farms, especially in summer, indicating localized eutrophication. A dispersion model showed waste from the farms could spread over 120 meters, mostly towards the coast. The benthic ecosystem was not significantly disturbed, though a biotic index found potential ecological risk in summer. Increased feeding and fish metabolism in summer, combined with seasonal currents, contributed to the localized nutrient increase near the farms.
Utilization of Multiple Habitat Sampling Protocol for Macroinvertebrates as Indicators of Water
Quality in Stream Ecosystem in Lawis,
Buruun, Iligan City
This study was aimed to know the sedimentation rate and the total suspended solid of the estuary in
relation to the implementation of melombo culture practice area. The sedimentation rate was measured using
sediment traps placed in 3 set stations and data were taken for 8 months of two weeks interval. The sediment
traps weremade of PVC pipe, 11.5 cm long and 5 cm diameter and located at 20 cm above the sea bottom.
Sediment samples were firstly soaked in freshwater for approximately 4 hours to remove salt content.
Sedimentation rate was determined as πr
2
h/time length, while Total Suspensi Solid (TSS) followed the formula
of Eaton, et al (1995). Results showed that the sediment trapped in station 1 ranged from 5.6 cm (109.9 cm3
) –
7.7 cm (151.11 cm3
) with an average of 6.61 cm (129.7 cm3
), station 2 from 5.3 cm (104 cm3
) to 8.5 cm (166.8
cm
3
) with an average of 7.18 cm (140.9 cm3
) and station 3 from 3.8 cm (74.6 cm3
) to 7.6 cm (149.2 cm3
) with an
average of 6.8 cm (133.8 cm3
), respectively. Total suspended solids (TSS) ranged from 18.28 to 50.60 with an
average of29.165 (29.59%) for station 1, 27.84 to 47.48 with an average of38.99 (39.56%) for station 2, and
18.28 to 50.60 with an average of 30.405 (30.85%) for station 3, respectively.Based upon the decree of Living
Environment Minister Numbered 51, 2004, for marine biota, the TSS has been above the standard seawater
quality.
This project examined how beach sand composition and tide levels affect the size and age distribution of butter clams. Samples were taken from beaches with varying elevations and sieved to determine sand composition. Statistical analysis found significant differences in clam age and size based on tide level, but not sand composition. The oldest clams were found at higher tide levels, while the youngest were at extreme high and low levels. This data on clam habitat requirements can inform sustainable harvest and farming strategies.
Inorganic and methylmercury do they transfer along a tropical coastal food ...racheltrans
This study evaluated methylmercury (MeHg) and inorganic mercury (Hginorg) concentrations in water, plankton, and fish from Guanabara Bay, a eutrophic coastal area in Brazil. The aims were to compare the trophic transfer and biomagnification of MeHg and Hginorg between different trophic levels in the food web, from plankton to predatory fish. Water, microplankton, mesoplankton, and muscle tissue from 7 fish species with different feeding habits were sampled. Results showed that MeHg concentrations and proportions increased with trophic level, while Hginorg decreased, indicating MeHg was the species that biomagnified. MeHg also reflected the vertical
Estrategias de medicación y técnicas .pptxearambulm3
El documento presenta estrategias para reducir errores en la administración de medicamentos por personal de enfermería. Se proponen seminarios de actualización farmacológica y mejor clasificación de medicamentos similares. El estudio evaluará estas estrategias mediante encuestas a 100 enfermeras en el hospital ISSSTE de Ensenada durante 3 turnos, analizando la variable de error de medicación.
More Related Content
Similar to 3.Environmental variability at a marine cage culture.pdf
Coastal marine ecosystem scientific paper swissmitchick
The document summarizes a study assessing the macrobenthic flora and fauna in the intertidal area of Dalipuga Beach in Iligan City, Philippines. Two 1-square-meter quadrats were placed in the transect line to analyze species composition. Only one algae species (Phaeophyta) was found in the first quadrat, while the second quadrat contained both algae and seagrass. Water temperature was 26-27°C, soil temperature was 25-26°C, humidity was 26%, sediment was sand and gravel, and pH and salinity were normal. No macrobenthic fauna was found.
Evaluation of the oyster farming potential of the Cintra bay (southern Morocco)Origins publication
The bay of Cintra is a marine ecosystem located in the southern Moroccan Atlantic known for its
biological richness and therefore for its high fishery productivity. This bay was chosen as a new destination for the
development of aquaculture in the southern regions of Morocco. To highlight its potential in terms of oyster
farming, a first rearing trial of triploid cupped oysters (Crassostrea gigas) as well as parallel monitoring of the
phytoplankton population and ecological parameters were undertaken. The results obtained showed that the oysters
adapt well to the conditions of the new environment where mortality was negligible, or even absent after a month
of launching. In terms of biological performance, the growth of individuals is continuous during the annual cycle
and after eight months the weight could reach 30.5 g which is a minimum weight for marketing. The AFNOR and
Lawrence and Scott indices showed a good physiological state and a better commercial quality of the oysters. The
filling rate of these oysters, with an average weight of 39.7g when lifting, is very high according to the Lawrence and
Scott index (126.3) and the average AFNOR index (around 21.8) rank them in the “Special” category.
AQUATIC GENETIC RESOURCES AND CLIMATE CHANGE_CleanPatrick White
This document provides an overview of the importance of aquatic genetic resources in the context of climate change. It discusses how aquatic ecosystems and the organisms they support play a key role in global carbon and nutrient cycles. Aquatic genetic resources underpin global aquaculture and fisheries, which together provide about half of the world's food fish and are important for food security, nutrition, and livelihoods. Climate change poses challenges for these resources and the sectors that depend on them through impacts like warming, acidification, and changes to freshwater availability. The roles of aquatic genetic resources in adapting to and mitigating climate change impacts are discussed.
Stress of Environmental Pollution on Zooplanktons and theirComparative Studi...theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
2009 assessment effects of cage culture on nitrogenearambulm3
This document summarizes a study that investigated nitrogen and phosphorus dynamics in relation to fallowing periods for a fish cage farm located in a shallow lake in China. The study analyzed total nitrogen and total phosphorus levels in lake water and sediment during two fish rearing cycles from 2000-2001. Key findings include:
1) Nutrient levels increased more during the first rearing cycle than the second.
2) Impacts were greatest near the cages (underneath and at cage sides), with higher sedimentation of nitrogen and phosphorus observed at cage sides.
3) After 3 months of fallowing, water nutrient levels decreased significantly but sediment nutrient levels remained high, indicating recovery occurs during fallowing
An Investigation into how Climate Driven Oceanic Warming may effect the Filtr...Ciara Condit
This study investigated how ocean warming may affect the filtration rates of the blue mussel (Mytilus edulis). Individual mussels were exposed to four temperature treatments (7°C, 16°C, 20°C, and 25°C) and their filtration rates measured. Statistical analysis found filtration rates increased significantly with higher temperatures, with the greatest difference between 7°C and 25°C. While filtration may increase in a warmer climate, overall mussel productivity is likely to decrease due to other climate impacts such as ocean acidification and reduced food availability.
Stomach histological decay of milkfish, chanos chanos (forsskal, 1775)Alexander Decker
This document summarizes a study on the histological decay of the stomach in milkfish (Chanos chanos) reared in a traditional brackishwater pond in East Java, Indonesia. Several factors were found to contribute to deterioration of the stomach, including environmental stress from heavy metals in the water, high ammonia levels, a shift in the natural food composition to cyanobacteria, and infection by the Myxobolus parasite. Earlier harvest, higher mortality, and smaller fish size compared to normal indicated declining productivity of traditional milkfish aquaculture in the region in recent decades.
This project monitored changes in phytoplankton communities in a eutrophic Irish lake over a 6-month period to determine the lake's health. Phytoplankton assemblages followed distinct successional stages that correlated with changing water quality. These assemblages provided evidence that the lake remained near the mesotrophic/eutrophic border despite rehabilitation efforts. The study evaluated phytoplankton's sensitivity as biological indicators of ecological status under the Water Framework Directive.
1) The document evaluates the management effectiveness of the National Natural Park Rosario and San Bernardo Corals marine protected area in Colombia using biological, socioeconomic, and governance indicators.
2) Biological surveys found low coral cover and fish diversity/abundance both inside and outside the MPA, suggesting limited effectiveness of current management. The reefs also showed signs of degradation.
3) Socioeconomic and governance analyses revealed low incomes for local communities, few opportunities, weak governance, and overexploitation of resources inside the MPA. This reflected low adaptive capacity to comply with conservation rules.
The document summarizes the mission and science-based work of the National Park Service at the Cape Cod National Seashore. It discusses inventorying, monitoring, and research efforts across various natural systems to understand resources, track changes over time, and inform adaptive management. Examples of current and future studies are provided covering topics like salt marsh restoration, water quality, species populations, climate change impacts, and more. The work involves interdisciplinary teams of scientists, technicians, and ecologists.
Effect of water parameters on temporal distribution and abundance of zooplank...AbdullaAlAsif1
Seasonal abundance of zooplankton in relation to different physico-chemical conditions of Kaptai lake has been studied. A total of four major groups of zooplankton were identified from study area of Kaptai lake during three seasons observation at pre-monsoon, monsoon and Post-monsoon. These four groups were categorized into rotifers, copepods, cladocerans and others (fish larvae, shrimp larvae, insects, mosquito larvae etc.). The mean abundance of group rotifers, copepods, cladoceras and others were 103, 84.67, 38.33 and 41.83 ind. L-1 respectively. The highest group was rotifers in terms of abundance and composition where compositions were recorded 38 % at three season's observation. The lowest group was cladoceras in term of abundance and composition where compositions were recorded 14 %. The air temperature, water temperature, transparency, water pH, DO, BOD5, PO 4-P, NO 2-N, SiO 3-Si, TSS, TDS, Alkalinity ranged between 21 and 27.5C, 23.5 and 31.5C, 0.8 and 3 m, 7.1 and 7.5, 5.72 and 8.58 mg/l, 8.55 and 12.87 mg/l, 3.22 and 4.13 µg/l, 0.992 and 1.19 µg/l, 161.18 and 201.15 µg/l, 0.28 and 0.48 g/l, 0.18 and 0.68 g/l, 40 and 60 ppm, respectively. Margalef richness index (d), Pielou's evenness index (J'), Shannon-Wiener diversity index (H'), Simpson dominance index (λ) are analyzed by Primer V6 software to quantify the collected species. Through same software SIMPER, Cluster analysis also done to compare similarity between season.
The effects of different water quality parameters on zooplankton distribution...iosrjce
IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) multidisciplinary peer-reviewed Journal with reputable academics and experts as board member. IOSR-JESTFT is designed for the prompt publication of peer-reviewed articles in all areas of subject. The journal articles will be accessed freely online
Intact Oceans and Their Benefits, by Edward Lohnes, Conservation InternationalWILD Foundation
The document discusses several papers that illustrate the benefits of healthy oceans. It summarizes that intact oceans are crucial for life on Earth and provide many services like food and climate regulation. However, oceans face many threats from human activities. Studies show that marine protected areas can help restore ecosystems and biodiversity by limiting fishing and other extractive activities. Recent research also finds that dynamic protection approaches may further help increase fish biomass. Additionally, protecting blue carbon sinks can significantly offset carbon emissions and help mitigate climate change. Comprehensive ocean zoning is needed to manage cumulative human impacts on marine environments.
IRREVERSIBLE? Climate Change, Fisherfolks, and the Coastal Communitymeih
The document discusses the impacts of climate change on coastal communities and fisheries in the Philippines. It notes that the Philippines has extensive coastlines and coastal populations that are highly dependent on marine fisheries for food and livelihood. Climate change is expected to negatively impact coral reefs, fisheries, and coastal resources through rising sea levels, increased temperatures, and more extreme weather. This will threaten food security and biodiversity in the Philippines. The document also discusses observed shifts in species ranges and abundances due to ocean warming globally.
Qualitative and quantitative analysis of phytoplankton in culture pond of Noa...AbdullaAlAsif1
A study was conducted on qualitative and quantitative analysis of phytoplankton in cultured ponds of two fish farms of Noakhali district, Bangladesh from 15 September to 15 November 2012 to identify and estimate the abundance of phytoplankton in various culture ponds of two fish farms. Analyses of phytoplankton samples recorded a total of 4 classes phytoplankton viz.; Bacillariophyceae, Chlorophyceae, Cyanophyceae, Euglenophyceae. Out of 21 phytoplankton genera identified, 5 belong to Cyanophyceae, 7 to Chlorophyceae, 5 to Bacillariophyceae and 4 to Euglenophyceae. Among the identified genera, Euglena, Microcystis, Eurolena were found to be dominant genera. Total phytoplankton abundance was varied from 36×105 cells/L to 94.92×105 cells/L in the experimental ponds. Among all experimental ponds, Chlorophyceae was found dominant (44.4×105 cells/L). Second dominant group was Euglenophyceae (39.6×105 cells/L) observed in pond-1 of Bismillah Agro Production (BAP). Total phytoplankton densities were recorded 47.82×105cells/L and 51×105 cells/L in pond-1 and pond-2 of Subarna Agro Based Initiative (SABI) respectively. In BAP, total phytoplankton densities were recorded 94.92×105cells/L and 36×105 cells/L in pond-1 and pond-2 respectively. Management technique and water quality parameters were also studied during study period namely water temperature, conductivity, salinity, transparency, dissolve oxygen and pH. The present study reveals that phytoplankton species are variable among the culture ponds and their density is also variable. The information provides for more research to compare water quality and pond phytoplankton characteristics in earthen aquaculture systems with and without fish stocking. Further studies on the seasonal changes of water quality parameters and its effects on phytoplankton production in the fish ponds and all year extended monitoring is recommended in future studies.
The document summarizes a study that monitored water quality and benthic ecosystems around fish farms in Igoumenitsa Bay, Greece between 2011-2012. Water samples found increased nutrients like phosphorus near the fish farms, especially in summer, indicating localized eutrophication. A dispersion model showed waste from the farms could spread over 120 meters, mostly towards the coast. The benthic ecosystem was not significantly disturbed, though a biotic index found potential ecological risk in summer. Increased feeding and fish metabolism in summer, combined with seasonal currents, contributed to the localized nutrient increase near the farms.
Utilization of Multiple Habitat Sampling Protocol for Macroinvertebrates as Indicators of Water
Quality in Stream Ecosystem in Lawis,
Buruun, Iligan City
This study was aimed to know the sedimentation rate and the total suspended solid of the estuary in
relation to the implementation of melombo culture practice area. The sedimentation rate was measured using
sediment traps placed in 3 set stations and data were taken for 8 months of two weeks interval. The sediment
traps weremade of PVC pipe, 11.5 cm long and 5 cm diameter and located at 20 cm above the sea bottom.
Sediment samples were firstly soaked in freshwater for approximately 4 hours to remove salt content.
Sedimentation rate was determined as πr
2
h/time length, while Total Suspensi Solid (TSS) followed the formula
of Eaton, et al (1995). Results showed that the sediment trapped in station 1 ranged from 5.6 cm (109.9 cm3
) –
7.7 cm (151.11 cm3
) with an average of 6.61 cm (129.7 cm3
), station 2 from 5.3 cm (104 cm3
) to 8.5 cm (166.8
cm
3
) with an average of 7.18 cm (140.9 cm3
) and station 3 from 3.8 cm (74.6 cm3
) to 7.6 cm (149.2 cm3
) with an
average of 6.8 cm (133.8 cm3
), respectively. Total suspended solids (TSS) ranged from 18.28 to 50.60 with an
average of29.165 (29.59%) for station 1, 27.84 to 47.48 with an average of38.99 (39.56%) for station 2, and
18.28 to 50.60 with an average of 30.405 (30.85%) for station 3, respectively.Based upon the decree of Living
Environment Minister Numbered 51, 2004, for marine biota, the TSS has been above the standard seawater
quality.
This project examined how beach sand composition and tide levels affect the size and age distribution of butter clams. Samples were taken from beaches with varying elevations and sieved to determine sand composition. Statistical analysis found significant differences in clam age and size based on tide level, but not sand composition. The oldest clams were found at higher tide levels, while the youngest were at extreme high and low levels. This data on clam habitat requirements can inform sustainable harvest and farming strategies.
Inorganic and methylmercury do they transfer along a tropical coastal food ...racheltrans
This study evaluated methylmercury (MeHg) and inorganic mercury (Hginorg) concentrations in water, plankton, and fish from Guanabara Bay, a eutrophic coastal area in Brazil. The aims were to compare the trophic transfer and biomagnification of MeHg and Hginorg between different trophic levels in the food web, from plankton to predatory fish. Water, microplankton, mesoplankton, and muscle tissue from 7 fish species with different feeding habits were sampled. Results showed that MeHg concentrations and proportions increased with trophic level, while Hginorg decreased, indicating MeHg was the species that biomagnified. MeHg also reflected the vertical
Similar to 3.Environmental variability at a marine cage culture.pdf (20)
Estrategias de medicación y técnicas .pptxearambulm3
El documento presenta estrategias para reducir errores en la administración de medicamentos por personal de enfermería. Se proponen seminarios de actualización farmacológica y mejor clasificación de medicamentos similares. El estudio evaluará estas estrategias mediante encuestas a 100 enfermeras en el hospital ISSSTE de Ensenada durante 3 turnos, analizando la variable de error de medicación.
Este documento describe los principales elementos fisicoquímicos y biológicos que actúan en los cuerpos de agua, incluyendo gases, iones, calor, luz, animales y plantas. Explica las zonas en los lagos, los orígenes de los lagos, y clasifica los lagos por su patrón anual de circulación. También resume los conceptos clave de limnología y ecosistemas acuáticos.
1) El documento describe las diferentes etapas del desarrollo científico, incluyendo la ciencia normal, las anomalías, las crisis y las revoluciones científicas. 2) Explica que la ciencia normal implica investigación basada en paradigmas existentes y la resolución de enigmas, mientras que las anomalías y crisis pueden conducir al surgimiento de nuevas teorías. 3) Las revoluciones científicas representan cambios no acumulativos donde viejos paradigmas son reemplazados por nuevos paradigmas incompatibles, lo
Este documento describe los principales elementos fisicoquímicos y biológicos que afectan la calidad del agua en los cuerpos lacustres, incluyendo gases, iones, calor, luz, animales y plantas. También explica conceptos como la estratificación térmica, las zonas en los lagos, los orígenes de los lagos, y las clasificaciones de los lagos según su patrón anual de circulación. Finalmente, presenta información sobre la importancia de la limnología para la acuicultura y la producción de pe
El documento describe los principios básicos de la fisiología animal, incluyendo la organización jerárquica de los seres vivos desde las células unicelulares hasta los sistemas de órganos, y los mecanismos de termorregulación. Explica que los organismos mantienen la homeostasis a través de mecanismos de retroalimentación negativa y la habilidad de ajustarse al medio ambiente. Además, clasifica a los animales como ectotermos u homeotermos dependiendo de si generan o no su propio calor metabólicamente
Theza Cabrera_presentacion de proyecto.pptxearambulm3
Este documento presenta un proyecto de investigación sobre los daños que ocasiona el uso excesivo de la tecnología en el desarrollo social y conductual de niños de preescolar. El proyecto plantea como objetivo principal analizar cómo afecta el uso excesivo de aparatos electrónicos a niños menores de 5 años e incluye una hipótesis, objetivos específicos y una metodología basada en encuestas a padres para evaluar el tiempo de uso, actividades realizadas y posibles efectos en el comportamiento y sueño de
El documento describe los anélidos, que son animales triblásticos y celomados con cuerpo segmentado y simetría bilateral. Los anélidos se dividen en poliquetos, que son principalmente marinos; oligoquetos, que son terrestres o de agua dulce; y hirudíneos, que carecen de sedas. El documento fue creado con fines educativos por Jose A. Pascual.
Este documento describe diferentes medidas de dispersión estadísticas como la desviación media, varianza, desviación estándar y coeficiente de variación. Explica las fórmulas para calcular cada medida y sus propiedades. También incluye ejemplos numéricos para ilustrar cómo calcular estas medidas a partir de conjuntos de datos.
Este documento proporciona información sobre diferentes tipos de gráficos estadísticos como diagramas de sectores, gráficos de columnas, histogramas, polígonos de frecuencias, curvas suavizadas y ojivas. Explica las características y cómo construir cada uno de estos gráficos en Excel. También incluye un ejemplo de cómo interpretar la información en una ojiva.
Este documento discute la evolución biológica del cerebro humano y su papel fundamental en el desarrollo de la ciencia. También describe brevemente los orígenes de la cultura occidental en la antigua Grecia y cómo la razón comenzó a separarse de la religión durante la Edad Media. Finalmente, analiza la complejidad de la relación entre la ciencia y la religión en la actualidad.
El documento discute la naturaleza androcéntrica y masculina de la ciencia occidental. Argumenta que la ciencia se ha construido sobre la base de la experiencia subjetiva de los científicos masculinos, ignorando otras formas de conocimiento. También critica la elevación de la razón y la objetividad por sobre la emoción y la subjetividad, lo cual excluyó a las mujeres de la ciencia. El feminismo científico ha revelado las limitaciones de esta visión masculina y ha buscado incorporar perspectivas y preguntas de investigación
Galileo Galilei nació en Pisa el 15 de febrero de 1564. Realizó sus primeros estudios en Pisa y Florencia. En 1586 inventó la balanza hidrostática y durante esta etapa realizó numerosos trabajos experimentales e inventó varios instrumentos matemáticos.
El documento discute los desafíos que enfrentan las plantas de balanceado en la formulación de dietas para acuicultura. Específicamente, destaca que a menudo las dietas se formulan para reducir costos sin considerar completamente los requerimientos nutricionales de las especies. También analiza estudios sobre la digestibilidad y asimilación de nutrientes para mejorar el diseño de dietas. Finalmente, propone que es necesario estudiar con mayor precisión el efecto de los nutrientes a nivel intestinal para optimizar el desempeño animal y la rentabilidad
La célula es la unidad funcional básica de todos los organismos vivos. Contiene una membrana, citoplasma con organelos como el retículo endoplasmático y mitocondrias, y en eucariotas un núcleo. El retículo endoplasmático sintetiza proteínas y lípidos, mientras que las mitocondrias generan energía. El aparato de Golgi procesa y empaqueta moléculas para su secreción o uso celular. Los lisosomas contienen enzimas para digerir materiales intern
El documento resume los diferentes métodos de transporte celular. Explica que la membrana celular controla el paso de sustancias a través de procesos pasivos como la difusión, la osmosis y la difusión facilitada, o activos como el transporte activo. También describe los mecanismos de endocitosis y exocitosis mediante los cuales las células pueden transportar materiales grandes a través de la membrana celular.
El documento habla sobre la regulación de las funciones corporales y la homeostasis. Explica que el cuerpo mantiene la homeostasis a través del control del volumen y concentración de los líquidos corporales como el líquido intracelular. El riñón juega un papel clave al mantener el volumen hídrico y la concentración de sales a través de la orina.
2.The combined effects of salinity and temperature on the proximate.pdfearambulm3
The document summarizes a study that examined the effects of different temperature and salinity combinations on the growth, survival, and proximate composition of juvenile spotted rose snapper (Lutjanus guttatus). It found that temperature had a significant effect on proximate composition, with higher temperatures increasing protein content and decreasing lipid and water content. The optimal temperature-salinity combination for growth, protein content, lipid content, and energy value was 30-32°C and 35 g/L salinity. Survival was highest at 25 g/L salinity across all temperatures. While temperature influenced composition, salinity had less effect except at the highest level tested (45 g/L), which negatively impacted growth and composition parameters.
1.The spotted rose snapper (Lutjanus guttatus Steindachner.pdfearambulm3
The document reviews growth models used to describe the growth of fish in aquaculture and applies several models to dataset of spotted rose snapper cultured in floating cages off the coast of Mexico. It finds that the Schnute growth model best describes the growth of the spotted rose snapper based on the Akaike information criterion. The study aims to demonstrate the importance of selecting the most appropriate growth model for aquaculture studies in order to improve production efficiency. A total of 558 weight-at-age data points were collected from spotted rose snapper cultured for 270 days in floating cages with a survival rate of 90% and average final weight of 429.84 grams.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
3.Environmental variability at a marine cage culture.pdf
1. 223
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
Revista de Biología Marina y Oceanografía
Vol. 53, N°2: 223-235, 2018
DOI: http://dx.doi.org/10.22370/rbmo.2018.53.2.1295
ARTICLE
Environmental variability at a marine cage culture
operation in the Matanchén Bay, SE Gulf of California,
Mexico
Variabilidad ambiental en un cultivo de jaulas marinas en la Bahía Matanchén, SE del Golfo de
California, México
Eulalio Arámbul1
, Sergio G. Castillo-Vargasmachuca1
, Jesús T. Ponce-Palafox1*
,
Federico Páez-Osuna2
, José Luis Arredondo-Figueroa3
and Héctor M. Esparza-Leal4
1
Programa de Posgrado de Maestría en Ciencias Biológico Agropecuarias, Laboratorio de Bioingeniería Costera, Universidad
Autónoma de Nayarit, Tepic, Nayarit, México 63000. *jesus.ponce@usa.net
2
Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Unidad Académica Mazatlán, Joel
Montes Camarena s/n, Mazatlán, Sinaloa, México 82040
3
Universidad Autónoma de Aguascalientes, Posta Zootécnica, Jesús María, Aguascalientes, México 20131
4
Instituto Politécnico Nacional, CIIDIR Unidad Sinaloa, Boulevard Juan de Dios Bátiz Paredes #250, Guasave, Sinaloa,
México 81101
Resumen.- Este trabajo presenta los resultados del análisis de las condiciones ambientales sobre el perfil físico-químico
de la columna de agua y sedimentos que son producidos por las jaulas flotantes y la influencia de escurrimientos
continentales en una granja de peces marina en el Sur este del Golfo de California, México. Veinte muestras de la columna
de agua y siete del sedimento fueron colectadas mensualmente durante un ciclo anual. Se analizaron parámetros físico-
químicos del agua y del sedimento. En general, los nitratos mostraron la más alta concentración de los nutrientes en las
estaciones de la zona de impacto potencial (1,92 mg L-1
). Hubo una variación temporal en la concentración de NH4
+
, NO3
-
y
PO4
3-
en la columna de agua, y en la concentración de arcilla y materia orgánica en sedimento, con una tendencia a
incrementarse en las estaciones de impacto potencial y control, respectivamente.
Palabras clave: Acuacultura marina, impacto ambiental, calidad del agua, calidad del sedimento
Abstract.- This study investigated the environmental impact of offshore floating sea cages and the influence of runoff on
cage fish farming in SE Gulf of California via the analysis of the physico-chemical profiles of the water column and sediments,
located in SE Gulf of California, Mexico. Water and sediment samples were analyzed for physico-chemical parameters. In
general, nitrates showed the highest concentrations of nutrients in the potential impact station (1.92 mg L-1
). The results
displayed temporal variations in the NH4
+
, NO3
-
, and PO4
3-
in the water column as well as variations in the clay and organic
matter in the sediment. The observed trends of these parameters were toward higher concentration in the potential
impact and control stations.
Key words: Marine aquaculture, environmental impact, water quality, sediment quality
INTRODUCTION
Marine finfish cage aquaculture has been developed in
various regions of the world with great success (Price et
al. 2015). However, this development has been
accompanied by environmental risk. Nowadays, there is
strong interest in advancing an industry ever more
profitable but in harmony with the environment (Grigorakis
& Rigos 2011). Regional efforts have been made in most
of the areas where floating sea-cage aquaculture has
grown (Holmer 2010). One of the main challenges facing
sea-cage aquaculture is the impact of the wastes from sea
farms on organisms in the surrounding areas (Price et al.
2015). The impact of these wastes can be reduced through
improved feed and proper location of farms (Grøttum &
Beveridge 2007). Finfish aquaculture in floating sea cages
has been carried out in three zones: onshore, nearshore,
and offshore (Holmer 2010). In recent years, Mexico has
developed a program to support development of finfish
culture in floating sea cages off the coast (i.e., farms
located 500 m to 3 km from nearshore and at a water depth
of 10 to 50 m). Currently, the information on the
environmental effects on off-coast farms is limited due to
2. 224 Arambúl et al.
Environmental variability in marine cage
the relatively few full-scale off-coast farms under
operation. Studies on the management of floating sea-
cage fish farming have evaluated the visual impact and
ecological footprint, benthic impacts, interactions with
wild fish and predators, use of antifoulants/chemicals,
carbon footprint, and water quality (Holmer 2010).
Sediment impacts are of primary concern in mariculture,
particularly where accumulation of organic matter may
result in anoxia/hypoxia and losses of benthic production
and biodiversity (Hargrave et al. 2008). Water quality is
one of the factors that may have less severe impacts (Sara
2007). The principal source of wastes in floating sea cages
is organic matter coming from the fish feed and feces
(Sanz-Lázaro & Marín 2011). It has been found that
approximately 1/4 of the nutrients supplied via fish feed
are incorporated into the fish meat itself, and 3/4 is widely
dispersed, with fast sinking rates of feed pellets and feces
causing organic enrichment of the bottom sediments in
farm vicinities (Holmer et al. 2005, Holmer 2010). Water
quality is affected by the release of dissolved and
particulate inorganic and organic nutrients. However,
limited impacts have been recorded in many places due
to rapid dispersal (Holmer 2010). Since the shelf area in
Mexico has not been widely monitored with respect to
the impacts of organic enrichment and the influence of
the mainland on farming systems, research related to
expansion of off-coast cage aquaculture in the region is
still needed. The aim of this study was to analyze the
water and sediment variability near a sea-cage fish farm,
and to evaluate the influence of continental runoff into
sea cages located in the Bay Matanchén, at the mouth of
southeastern Gulf of California, Mexico.
MATERIALS AND METHODS
STUDY AREA
This study was conducted at the Matanchén Bay on the
eastern coast of the mouth of the Gulf of California (Fig.
1). The site is known as ‘Punta el Caballo’ beach along the
Nayaritcoast,Mexico(21°25´55.44"N,105°12´26.63"W). The
cultivation area is located at 0.514 km from the mouth of
the Naranjo River (21°26´03.01"N, 105°12´12.17"W), within
the area of influence of riverine discharges during the
flood season, mainly due to the contribution of total solids
(Castillo-Vargasmachuca et al. 2012). The sea-cage fish
farming facility is located in the open sea, about 1.5 km
from the coastline within the polygon concession
allocated to the Cooperative ‘Blakis in Progress S.C. of
R.L’ in Santa Cruz de Miramar, San Blas, Nayarit. This
area has a floating sea-cage fish farm producing 30 tons
year-1
of snapper and tilapia over two cycles per year.
The culture farm comprised two sets of 10 floating cages
each (5 × 5 × 5 m), constructed with nylon-10 (tarred
polyamide) netting each. The cages were equipped with
200-L plastic and 50-L glass sealed drums as the flotation
system, suspended 15 m above the sandy bottom, 5 m
apart, and aligned to the main Pacific current. These cages
were used to rear snapper Lutjanus guttatus and L. peru
(Castillo-Vargasmachucaetal.2007,Castillo-Vargasmachuca
et al. 2012) as well as tilapia Oreochromis niloticus. This
unit had been operating for 2 years (4 production cycles)
when our investigation started of the 5th production cycle.
The culture strategy was one phase. The fish were fed
daily using commercial feed (NUTRIPEC-Purina: 42%
protein, 12% lipids, and 10% moisture), dispensed manually
from a small boat.
SAMPLING STRATEGY
This study covered a one-year cycle with measurements
taken from selected sampling points that are located inside
and around the cage system and are separated by a mean
distance of about 500 m. The particular unit monitored
was a group of 10 cages, arranged in a northwest-
southeast direction. The water depth at this site ranged
from 18 to 20 m, the mean current velocity was 10.4 ± 2.0
cm s-1
and the predominated directions were NW–SE, as
measured (more than 80% of the time) by an automatic
current-meter (Aanderaa Instruments, Inc. Mod. RCM-7,
Norway). Twelve sampling stations were established to
determine the seasonal changes in the physico-chemical
profiles of water and sediment. Samples of the water
column were collected monthly during an annual cycle
and grouped into three zones and seasons of the year for
analysis: 4 points as the facility (2 in cages and 2 outside
cages); 4 upstream sampling areas as the controls; and 4
points in the impact downstream of the farm. At each
sampling point, samples were collected from the surface
(0 m), mid-water (10 m), and the bottom (20 m) (Fig. 2). In
total, there were 8 stations, 200 to 500 m away from the
facility, and four positioned in floating cages, downstream
in the main current direction (Fig. 1). Samples of water
and sediment were collected during 12 sampling trips
(September 2014 through August 2015). In the sampling
stations, samples of unaltered sediment layers were taken
using a Van Veen grab (0.1 m2
; 20 L) equipped with screen
doors. In four stations of the sediments, the sample was
3. 225
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
collected by divers using ‘sampling boxes’ (35 x 35 x 20
cm, 24 L) used to obtain a comparable content to the Van
Veen grab. Special care was taken to collect the top (0-5
cm) of the sediments in both cases.
PHYSICO-CHEMICAL ANALYSIS
The samples of the water column were collected using a
Niskin-type water sampler (3 L). Temperature, salinity, and
dissolved oxygen (DO) were measured utilizing a multi-
parameter instrument YSI Pro-2030 (YSI, Yellow Springs,
OH, USA). The pH was measured with a portable
potentiometer Hi 98127 (Hanna Instruments, TX, USA). The
dissolved nutrients [dissolved inorganic nitrogen DIN=
ammonium (NH4
+
) + nitrates (NO3
-
) + nitrites (NO2
-
)] and
soluble reactive phosphorus (PO4
3-
)] were analyzed. For
this purpose, the water samples were filtered using a
nitrocellulose membrane filter with a pore size of 0,45 µm
(Millipore HA), and the nutrients were determined by
colorimetric methods (Strickland & Parsons 1972) with a
spectrophotometer YSI 9100 (YSI, Yellow Springs, OH,
USA). Chlorophyll ‘a’ (Chl-a) and water organic matter
(WOM) were determined using the time series database
Giovann by employing the superficial (0 and 10 m) water
samples only. These data were obtained in quarterly time
series produced by the Aqua-Modis satellite with a
maximum reading in the study area of 4 km.
Granulometry was performed on the sediment samples
using the Wentworth scale. The combustion method was
used in determining the sediment organic matter (SOM)
(Dell’Anno et al. 2002). The total nitrogen (TN) was
obtained by the Kjeldhal method (AOAC 1985). The total
phosphorus (TP) was evaluated in the dried samples,
which were homogenized by grinding and digested with a
mixture of concentrated perchloric and nitric acid (Sturgeon
et al. 1982). The TP was determined colorimetrically as
molybdate reactive phosphorus (Strickland & Parsons 1972).
In addition, we calculated the N:P ratio (nitrogen:phosphorus)
for water and sediment.
STATISTICAL ANALYSIS
The data was grouped into four seasons according to the
grouping of discriminant analysis (Fig. 5). The data were
logarithmically transformed to create a normal distribution.
Analysis of variance (ANOVA) was used to determine
the overall significance of differences among samples and
seasons on variations in physico-chemical parameters in
waters and sediments. The post hoc Tukey’s HSD test
was applied to determine statistically significant
differences (P < 0.05) following ANOVA. The effects of
spatial and temporal variation were analyzed by cluster
and discriminant analysis using Statistica 5.5 (Statsoft
Inc. OK, USA) package software.
Figure 1. Study area and sampling stations at the Matanchén Bay, Nayarit coast, Mexico / Área de estudio y estaciones de muestreo
en Bahía Matanchén, costa de Nayarit, México
4. 226 Arambúl et al.
Environmental variability in marine cage
Figure 2. Temperature, dissolved oxygen, dissolved inorganic nitrogen (DIN) and phosphates (PO4
3-
) in the water column
at the control, facility and potential impact stations, for an annual cycle (2014-2015) / Temperatura, oxígeno disuelto,
nitrógeno inorgánico disuelto (DIN) y fosfatos (PO4
3-
) en la columna de agua en las estaciones de control, jaulas
flotantes e impacto potencial para un ciclo anual (2014-2015)
5. 227
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
RESULTS
WATER COLUMN ANALYSIS
No significant differences in water temperature, salinity,
pH, and dissolved oxygen were found between the facility,
potential impact, and control stations, but there were
seasonal variations in these parameters (Table 1).
Generally, a relationship was found between the rainy
season and runoff with higher current velocity, temperature,
ammonia, nitrites, nitrates, phosphates, Chl-a, and lower pH.
Specifically, the current velocity (8.1 and 13.4 cm s-1
) and
rainfall (50 and 278.4 mm) were significantly lower in the
fall and higher during the summer season, respectively.
The lowest temperature was recorded in winter (26 °C)
and the highest in summer (31.9 °C) at the facility and
potential impact station, respectively. There were no
significant differences in the temperature of the water
column. The highest salinity (38.0 g L-1
) was recorded in
spring and the lowest in fall (34.6-34.8 g L-1
). The lowest
pH (7.4-7.6) and DO (4.5-5.0 mg L-1
) were recorded in
summer and fall, respectively. The DO concentrations in
the water were lower and significantly different at the
facility (4.5 mg L-1
) in fall season as compared to other
seasons (Table 1). Regarding the concentration of DO in
the water column (0 to 20 m), the greatest difference (6.5
to 3.7 mg L-1
) was found in winter. The greatest variation
of nutrients was measured at the facility in the fall and
winter seasons, and in the potential impact stations
during the spring and summer ones. In general, the highest
concentration of nitrates (1.92 mg L-1
) was found in the
potential impact stations. Differences in the vertical
Table 1. Environmental parameters of the water column by season of the year in the sea cage fish farm in control (C), Facility (FA)
and potential impact (PI) stations / Parámetros ambientales de la columna de agua por época del año en la granja de peces
de jaulas flotantes en las estaciones de control (C), jaulas flotantes (FA) e impacto potencial (PI)
6. 228 Arambúl et al.
Environmental variability in marine cage
SEDIMENT ANALYSIS
The floating sea-cage facility, potential impact and control
stations were characterized by sandy sediments. The
highest percentage of clay was found in the control
station as compared to the facility and potential impact
station, and a greater proportion of silt was identified in
the control station relative to the facility and potential
impact station (Table 2). The highest variability of clay
content was found in the potential impact station.
Significant differences in TP and SOM content were found
between the sediment samples from the facility and control
station. The greatest variability of SOM and NT was
recorded in winter. The lowest current speed (fall season)
was significantly associated with the highest
concentration of WOM, TN, and SOM. The N:P ratio in
the sediment had the highest values (8.8 to 10.5) in fall,
the lowest (3.6 to 6.1) in spring, and the greatest variability
in winter.
Table 2. Sediment parameters (%) by season of the year in the sea cage fish farm in control (C), facility (FA) and potential impact (PI) stations
/ Parámetros del sedimento (%) por época del año en la granja de peces de jaulas flotantes en las estaciones de control (C), jaulas
flotantes (FA) e impacto potencial (PI)
profiles of DIN across the water column were found. The
vertical profiles for PO4
3-
distribution displayed
significantly higher concentrations in the facility in the
winter and in the potential impact stations during the
summer. The significantly lower concentrations of WOM
and Chl-a were recorded to be 0.49 mg L-1
and 4.70 mg m-3
,
respectively in the spring season. It was also found that
the highest standard deviation of the parameters of water
(temperature, salinity, pH, DO, PO4
3-
, Chl-a and N:P ratio)
were recorded during fall. Our findings indicated that the
high levels of ammonium (1.26-1.31 mg L-1
), nitrite (0.19-
0.27 mg L-1
), nitrate (1.60-1.92 mg L-1
), phosphates (0.41-
0.51 mg L-1
), and Chl-a (7.6 mg m-3
) were present in summer.
The N:P ratio in the water showed its highest values (29.1
to 37.8) and the greatest variability in fall and its lowest
values (13.4 to 17.8) in spring.
7. 229
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
The cluster analysis of the water and sediment
parameters revealed two groups: the water parcel
represented by salinity and temperature and the
interaction of the physico-chemical parameters of water
and sediment (Fig. 3). Significant relationships were found
between the clay and the organic matter and nutrients of
the sediment, as well as between the clay and the
phosphorus and nitrites of the water column.
The discriminant analysis showed the differentiation
of three different groups of stations (Fig. 4), and a closer
relationship between facility and potential impact stations
throughout the year. In addition, our analysis
differentiated seasonal characteristics based on the water
quality and sediment samples of the facility, potential
impact, and control stations. Environmental conditions
could be grouped into 4 seasonal clusters, corresponding
to the months and predominant seasons of the year:
October to February (fall-winter), March to May (spring),
June to August (summer), and the last in September (Fig.
5). The main parameters that were found to distinguish
the groups in the discriminant analysis were temperature,
the rainy season, and current velocity.
DISCUSSION
The detection and explanation of the physico-chemical
dynamics of sea-cage fish farms require the knowledge
of water-column dynamics to explain the complex
changing aspects of the underlying sediment (Sara 2007).
The dominant current direction in this study area was
found to be southeast, which minimizes the possibility of
influencing the control station by wastes from sea-cage
fish farms. The current velocities and heights of the water
column during the study periods ranged from 8.1 to 13.4
cm s-1
and 18 to 20 m, respectively. These speeds were
within the magnitude range recorded in sea-cage fish farms
in areas of high aquaculture production (Morata et al.
2015, Price et al. 2015, Tomassetti et al. 2016). In general
terms, the literature has demonstrated that good
management of marine areas recommends placing the
cages in areas of mean current > 7 cm s-1
(Price et al. 2015)
and with water depth that is at least twice that of the
floating cage (Belle & Nash 2008). These guidelines help
promote the dispersion and dilution of the nutrients for
natural assimilation.
Figure 3. Cluster analysis of water column and sediment parameters. SAL, salinity; TEM, temperature; PO4, phosphate;
NO2, nitrite; OMW, organic matter in water; OMS, organic matter in sediment; TP, total phosphate; TN, total nitrogen;
CLA, clay; NO2, nitrate; NH4, ammonium; SIL, silt; PH, pH; OXY, dissolved oxygen; SAN, sand; CHLA, Chl-a; NPW, N:P ratio
in water; NPS, N:P ratio in sediment / Análisis de clúster de los parámetros de la columna de agua y sedimento
8. 230 Arambúl et al.
Environmental variability in marine cage
Figure 4. Discriminant analysis of water column and sediment parameters sample stations, for an annual cycle (2014-2015) / Análisis de
discriminante de los parámetros de las estaciones de la columna de agua y sedimento, de un ciclo anual (2014-2015)
Figure 5. Discriminant analysis of water column and sediment parameters for an annual cycle (2014-2015) / Análisis de discriminante
mensual de los parámetros de las estaciones de la columna de agua y sedimento, durante un ciclo anual (2014-2015)
9. 231
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
No thermocline was observed throughout the year (Fig.
2). The DO concentrations (4.5 to 5.7 mg L-1
) were higher
than the farm’s critical value (3.7 mg L-1
) for sustainable
aquaculture production (Abo & Yokayama 2007). The
lower DO values were observed in the fall season, due to
the high temperature and greater WOM concentration
(Fig. 2). The DO concentration was generally lower in
fall, winter, and summer seasons at the facility relative to
the control and potential impact stations. The lowest DO
was determined in the bottom layer (Fig. 2). This could be
an indication of higher oxygen consumption directly by
decomposition of settled particulate matter and/or fish as
well as oxidation of their metabolic products. These results
are similar to those reported under the cages of
Dicentrarchus labrax and Sparus aurata farms in the
Mediterranean Sea (La Rossa et al. 2002) and salmon farms
in Chile (Soto & Norambuena 2004). The highest
registered concentrations of DIN in the water column were
due to NO3
-
, NH4
+
, and NO2
-
; in order of importance. The
highest concentration of NO3
-
was found probably due
to the rapid oxidation of NH4
+
and NO2
-
for oxygenation
of the water column (Dosdat 2000). Generally, lower
concentrations of DIN were measured from fall to spring
seasons relative to those measured in summer. This
reflects the dynamics caused by summer stratification of
the water column due to increased temperature and
irradiance (Maldonado et al. 2005). Moreover, differences
between the facility and control stations were observed
during the winter season for the concentrations of PO4
3-
in the water column. This can be attributed to the presence
of phosphorus compounds and SOM in the sediment
(Table 2). Some previous studies on small-scale sea-cage
fish farms have not reported differences for any of the
parameters measured in the water column (oxygen or
nutrients) and control station (Kaymakci-Basaran et al.
2010). Sea-cage fish farms are expected to produce waste
characterized in large proportions of N and P in solute
form released into the water column. There may be
concerns about increased primary production and other
trophic impacts near farms. However, some studies of
plankton in the areas of influence of fish farming have
shown no significant differences between cage sites and
controls (Pitta et al. 1999). In some studies, only seasonal
differences have been evidenced around the cage
systems (Price et al. 2015), in a similar manner to the results
here. However, differences between facility and control
stations have often been detected in bays with lesser
circulation and in industrial-scale cage fish farms (La
Rossa et al. 2002, Yucel-Gier et al. 2007, Morata et al.
2015).
It is well documented that most of the nitrogen in the
water column was found in dissolved form, and even the
low particulate nitrogen output (Cho & Bureau 2001)
underwent fast biochemical degradation and reincorporated
into the water column once it settles down (Cromey et al.
2002). On the other hand, the higher values observed in
all stations in our study site might have been influenced
by the nearby floodway stream and domestic sewage
loads, which continuously emit fine sediments (nutrients
from agricultural by-products). It is also known that in
the water column of the study area, ammonia is quickly
oxidized to nitrate, which is less toxic (Dosdat 2000). Our
results have shown that increased nutrients (DIN) only
occur in the lower part of the water column, mainly in
summer (Fig. 2). This is likely a result of the periodic
influence of the Naranjo River, which discharges in the
Matanchén Bay where the fish cages are located,
increasing the sedimentation rate of particulate organic
materials in this area. Increased benthic fluxes of nutrients
at the sea-cage fish farm under riverine influence have
been observed in cage fish farms in other areas of the
world (Baric et al. 2002, Matijevic et al. 2009). It was found
that the water column variation is due to nutrient runoff
along the continental water and to the changes in the
DIN and PO4
3-
ratios induced by anthropogenic activities.
This seasonal incidence has been reported for other
nearshore sea cage systems in Mediterranean waters (Vila
et al. 2001, Olivos et al. 2002). This could be due to several
factors. Specifically, the hydrodynamics of the study area
might have contributed to the dilution and dispersion of
total solids and nutrients supplied by the shore. However,
it is challenging to assess whether the water quality is
being affected by the sea cages in the area of influence
and at longer time scales using the present information
(Grant 2010). This is further complicated by the
anthropogenically-derived nutrients in the coastal marine
water, making it difficult to quantify the proportion of
each of the sources including aquaculture (Price et al.
2015). The observed changes of parameter in the water
column were predominantly due to the seasonal weather
patterns of the Matanchén Bay, since they occurred at
the facility, potential impact, and control stations. Spatial
and temporal distribution of nutrients and their ratios
indicated the weak influence of the floating sea-cage fish
10. 232 Arambúl et al.
Environmental variability in marine cage
farm on the dissolved nutrient pool. However, many
authors have demonstrated that the water column can
also record some effects on short- and medium-temporal
terms (Handerson et al. 1997). In this study, these effects
were not detected, most likely due to by the low level of
production of snapper and tilapia (30 ton year-1
). The
maximum concentration of Chl-a was 7.6 mg m-3
in summer,
which was below the recommended maximum of 10 mg m-3
(Pitta et al. 1999) as an environmental quality standard to
avoid eutrophication, particularly for the coastal zone
(Yucel-Gier et al. 2007).
Small differences in particle size were observed
between the different stations during the annual cycle
(Table 2). There was a slight increase of the finest fraction
in fall and winter seasons. The presence of floating cages
did not appear to result in a decrease in water current
velocity, leading to the settlement of bigger particles close
to the system, as was reported at a marine cage farm in
Gran Canaria Island (Molina-Domínguez et al. 2001). The
OM and TP concentrations in the sediments observed in
other sea-cage fish farm were similar to those measured
in this study (Karakassis et al. 1998, Porrello et al. 2005,
Morata et al. 2015). The highest OMS content was found
at fall season, due to the higher rates of organic matter
deposition from terrigenous contributions probably
associated to Naranjo River by runoff effects for the rainy
season (Castillo-Vargasmachuca et al. 2012). This input
of organic matter at the water column and sediment surface
increases the oxygen consumption due to the increased
metabolism of the system (Morata et al. 2012). Organic
matter in surface sediment is an important source of food
for benthic fauna (Tomassetti et al. 2016). However, an
overabundance of OM may lead to reduction in species
richness, abundance and biomass, and the remediation
of enriched sediments may take several years (Pereira et
al. 2004). The TP concentrations recorded in the present
study were relatively high in the sediment (Karakassis et
al. 1998, 1999, Porrello et al. 2005). The results of this
study suggest that no detectable accumulation of solid
particulate wastes, as well as lower organic enrichment
from the marine cage farm, had taken place after two years
of operation. These findings were mainly because the
current velocity contributes to the dispersion of nutrients
(Black & McDougall 2002), thus avoiding the undesirable
effects of organic sediment accumulation (Yokoyama
2003). In addition, the distance between the sea-cage floor
and the bottom of the sea (12 to 15 m) facilitates waste
dispersal (Porrello et al. 2005). It has generally been
reported that the results of the effects on primary
production resulting from eutrophication are highly
variable (Price et al. 2015). Increased nutrient loading has
little or no detectable impact in some places, and we
conclude this was the case at this site during our study.
However, it is convenient that in the summer (due to the
increase of nutrients in the water column) the biomass of
the farm is adjusted to reduce the environmental impacts
and scaling up to industrial Aquaculture production could
be harmful given that the site does have high
concentration of nutrients in that season.
The molar N:P ratio for the water and sediment stations
varied from 13.4 to 37.8 and 3.8 to 10.54, respectively. The
ratio in water was usually higher than the Redfield atomic
ratio of 16:1 (Turner et al. 2006). In the sediment, it was
below the Redfield ratio, which is indicative of nitrogen-
limited sediment (Guildford et al. 2000) that has already
been reported in the region for several coastal waters
(Páez-Osuna et al. 2013). Phosphorus was limited in some
stations during winter and summer, and in all stations
throughout autumn seasons. This might be because the
rain and ocean currents help in keeping the TN in surface
ocean water, whereas phosphorus is lost as sedimentation
(Páez-Osuna et al. 2013).
The most sensitive parameters in our study were found
to be N:P, Chl-a, ammonium and phosphates in the water,
and clay, SOM, and N:P in the sediment. They showed
significant changes related to the distance from the sea
cages and the annual seasonal cycle (Fall-Winter and
Spring-Summer). However, it is worth mentioning that
although the measured concentrations clearly depict the
influence of the fish farm especially on the sediments,
their values were, in general, considerably lower than
those reported in the related studies on sea-cage fish
farms (Mantzavrakos et al. 2007, Fodelianakis et al. 2015,
Samuelsen et al. 2015, Tomassetti et al. 2016). Few studies
on the coasts of the Nayarit state have investigated the
physical aspects (e.g., depth, latitude, current profile) of
the cage farms floating in the sea, their management
characteristics (e.g., cultured species, volume of cages,
biomass, feeding rate) and water quality, or over repeated
production cycles. Hence, additional research in this
region of Mexico would be beneficial. It is considered
necessary to study the biogeochemical processes
induced by marine cage aquaculture (nutrients, food
pellets, and dissolved oxygen) that can affect food web
dynamics (Piroddi et al. 2011).
11. 233
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
In conclusion, monitoring the physical and chemical
properties of the water column and sediments at a floating
sea-cage fish farm in Matanchén Bay (SE of the mouth of
Gulf of California) revealed changes regarding the natural
state of the environment. A minor influence of fish
aquaculture on the water quality and sediments was
demonstrated. Seasonal changes were also observed in
terms of increased nitrate and phosphate concentrations
in the water column, and clay and OMS in the sediment.
The current (> 5 cm s-1
), depth (12 to 15 m beneath cages),
DO (mean minimum 4.5 mg L-1
), and low level of fish
production (30 ton year-1
) contribute to a rapid turnover
of the organic biodeposits, which were transformed and
diluted at a fast rate. However, it was found that at the
beginning of the autumn season, the rate current attained
the lowest value of the year (8.1 cm s-1
) and the SOM
concentrations (6.1 to 8.7 %) were the highest. Temporal
changes observed for most of the variables show a typical
seasonal pattern in all stations. The impact of farming on
the water column must be further investigated in terms of
continuous input of dissolved organic carbon and
nutrients that increase the background levels, rather than
as a process able to modify the natural seasonal variability.
The comparative analysis of physico-chemical parameters
of the water column and sediments in the cage fish farm
showed that floating culture cages induced a lower
disturbance in the open sea environment due to the
relatively low level of production per operating area and
the prevailing oceanographic conditions.
LITERATURE CITED
Abo K & H Yokayama. 2007. Assimilative capacity of fish
farm environments as determined by the benthic oxygen
uptake rate: studies using a numerical model. Bulletin of
National Fisheries Research and Development Agency 19:
79-87.
AOAC. 1985. Official methods of analysis of the Association
ofAnalytical Chemistry, 14th
edition.Association of Official
Analytical Chemists, Washington.
Baric A, G Kuspilic & S Matijevic. 2002. Nutrient (N, P, Si)
fluxes between marine sediments and water column in
coastal and open Adriatic. Hydrobiologia 475: 151-159.
Belle SM & CE Nash. 2008. Better management practices for
net-pen aquaculture. In: Tucker CS & JA Hargreaves (eds).
Environmental best management practices for aquaculture,
pp. 261-330. Wiley-Blackwell, Oxford.
Black KD & N McDougall. 2002. Hydrography of four
Mediterranean marine cage sites. Journal of Applied
Ichthyology 18: 129-133.
Castillo-Vargasmachuca SG, JT Ponce-Palafox, E Chavez-
Ortiz & JLArredondo-Figueroa. 2007. Effect of the initial
stocking body weight on growth of spotted rose snapper
Lutjanus guttatus (Steindachner, 1869) in marine floating
cages. Revista de Biología Marina y Oceanografía 42(3):
261-267.
Castillo-Vargasmachuca SG, JT Ponce-Palafox, M García-
Ulloa, JLArredondo-Figueroa,ARuiz-Luna, E Chávez-
Ortiz & AG Tacon. 2012. Effect of stocking density on
growth performance and yield of subadult Pacific red
snapper Lutjanus peru (Pisces: Lutjanidae), cultured in
floating sea cages. NorthAmerican Journal ofAquaculture
74: 413-418.
Cho CY & DP Bureau. 2001. A review of diet formulation
strategies and feeding systems to reduce excretory and feed
wastes in aquaculture. Aquaculture Research 32(1): 349-
360.
Cromey CJ, TD Nickell, KD Black, PG Provost & CR
Griffiths. 2002. Validation of fish farm waste resuspension
model by use of a particulate tracer discharged from a point
source in a coastal environment. Estuaries 25(5): 916-929.
Dell’Anno A, ML Mei, A Pusceddu & R Danovaro. 2002.
Assessing the trophic state and eutrophication of coastal
marine systems: a new approach based on the biochemical
composition of sediment organic matter. Marine Pollution
Bulletin 44: 611-622.
Dosdat A. 2000. Environmental impact of aquaculture in the
Mediterranean: nutritional and feeding aspects.
Environmental Impact Assessment of Mediterranean
Aquaculture Farms. Cahiers Options Méditerranéennes
CIHEAM-FAO 55: 23-36.
Grant J. 2010. Coastal communities, participatory research,
and far-field effects of aquaculture. Aquaculture
Environment Interactions 1: 85-93.
Grigorakis K & G Rigos. 2011. Aquaculture effects on
environmental and public welfare the case of Mediterranean
mariculture. Chemosphere 85: 899-919.
Grøttum JA & M Beveridge. 2007. A review of cage
aquaculture: northern Europe. In: Halwart M, D Soto & JR
Arthur (eds). Cage aquaculture: regional reviews and global
overview. FAO Fisheries Technical Papers 498: 126-154.
Guildford SJ, E Robert & RE Hecky. 2000. Total nitrogen,
total phosphorus, and nutrient limitation in lakes and oceans:
Is there a common relationship. Limnology and
Oceanography 45(6): 1213-1223.
Handerson RJ, DAM Forrest, KD Black & MT Park. 1997.
The lipid composition of sealoch sediments underlying
salmon cages.Aquaculture 158: 69-83.
Hargrave BT, M Holmer & CPNewcombe. 2008. Towards a
classification of organic enrichment in marine sediments
based on biogeochemical indicators. Marine Pollution
Bulletin 56: 810-824.
12. 234 Arambúl et al.
Environmental variability in marine cage
Holmer M. 2010. Environmental issues of fish farming in
offshore waters: perspectives, concerns, and research needs.
Aquaculture Environment Interactions 1: 57-70.
Holmer M, D Wildfish & B Hargrave. 2005. Organic
enrichment from marine finfishAquaculture and effects on
sediment biogeochemical processes. In: Hargrave BT (ed).
Environmental effects of marine finfish aquaculture, pp.
181-206. Springer, Berlin.
Karakassis I, E Hatziyanni, M Tsapakis & W Plaiti. 1999.
Benthic recovery following cessation of fish farming: a series
of successes and catastrophes. Marine Ecology Progress
Series 184: 205-218.
Karakassis I, M Tsapakis & E Hatziyanni. 1998. Seasonal
variability in sediment profiles beneath fish farm cages in
the Mediterranean. Marine Ecology Progress Series 162:
243-252.
Kaymakci-Basaran A, M Aksu & O Egemen. 2010. Impacts
of the fish farms on the water column nutrient concentrations
and accumulation of heavy metals in the sediments in the
eastern Aegean Sea (Turkey). Environmental Monitoring
and Assessment 162: 439-451.
La Rossa T, S Mirto, E Favaloro, B Savona, G Sará, R
Danovaro &AMazzola. 2002. Impact on the water column
biogeochemistry of a Mediterranean mussel and fish farm.
Water Research 36: 713-721.
Maldonado M, MC Carmona, Y Echeverría & A Riesgo.
2005. The environmental impact of Mediterranean cage
fish farms at semi-exposed locations: does it need a re-
assessment? Helgoland Marine Research 59: 121-135.
Mantzavrakos E, M Kornaros, G Lyberatos & P Kaspiris.
2007. Impacts of a marine fish farm in Argolikos Gulf
(Greece) on the water column and the sediment.
Desalination 210(1-3): 110-124.
Matijevic S, G Kuspilic, M Morovic, B Grbec, D Bogner, S
Skejic & J Veza. 2009. Physical and chemical properties
of the water column and sediments at sea bass/sea bream
farm in the middleAdriatic (Maslinova Bay).ActaAdriatica
50(1): 59-76.
Molina-Domínguez L, G López-Calero, JM Vergara-
Martín & LRobaina-Robaina. 2001.Acomparative study
of sediments under a marine cage farm at Gran Canaria
Island (Spain). Preliminary results. Aquaculture 192: 225-
231.
Morata T, J Sospedra, S Falco & M Rodilla. 2012. Exchange
of nutrients across the sediment-water interface below a
marine fish farm of Sparus aurata in the Western
Mediterranean Sea. Journal of Soils and Sediments 12: 623-
1632.
Morata T, S Falco, I Gadea, J Sospedra & M Rodilla. 2015.
Environmental effects of a marine fish farm of gilthead
seabream (Sparus aurata) in the NW Mediterranean Sea on
water column and sediment. Aquaculture Research 46: 59-
74.
Olivos A, MO Mas & J Camp. 2002. Continental runoff of
nutrients and their possible influence over stoichiometric
ratios (DIN:P:Si) in the northeastern Mediterranean waters
of Spain (Catalan Sea). Ciencias Marinas 2: 393-406.
Páez-Osuna F, A Piñón-Gimate, MJ Ochoa-Izaguirre, AC
Ruiz-Fernández, G Ramírez-Reséndiz & R Alonso-
Rodríguez. 2013. Dominance patterns in macroalgal and
phytoplankton biomass under different nutrient loads in
subtropical coastal lagoons of the SE Gulf of California.
Marine Pollution Bulletin 77: 274-281.
Pereira PMF, KD Black, DS McLusky & TD Nickell. 2004.
Recovery of sediments after cessation of marine fish farm
production. Aquaculture 235: 315-330.
Piroddi C, G Bearzi & V Christensen. 2011. Marine open
cage aquaculture in the eastern Mediterranean Sea: a new
trophic resource for bottlenose dolphins. Marine Ecology
Progress Series 440: 255-266.
Pitta P, I Karakassis, M Tsapakis & S Zivanovic. 1999.
Natural vs. mariculture induced variability in nutrients and
plankton in the eastern Mediterranean. Hydrobiologia 391:
181-194.
Porrello S, PTomassetti, LManzueto, MG Finoia, E Persia,
I Mercatali & P Stipa. 2005. The influence of marine
cages on the sediment chemistry in the western
Mediterranean Sea. Aquaculture 249: 145-158.
Price C, KD Black, BT Hargrave & JA Morris Jr. 2015.
Marine cage culture and the environment: effects on water
quality and primary production. Aquaculture Environment
Interactions 6: 151-174.
Sanz-Lázaro C &AMarín. 2011. Diversity patterns of benthic
macrofauna caused by marine fish farming. Diversity 3:
176-199.
Sara G. 2007. Aquaculture effects on some physical and
chemical properties of the water column: a meta-analysis.
Chemical and Ecology 23: 251-262.
Soto D & F Norambuena. 2004. Evaluation of salmon farming
effects on marine systems in the inner seas of southern
Chile: a large scale measurement experiment. Journal of
Applied Ichthyology 20: 493-501.
Strickland JDH & TR Parsons. 1972. A practical handbook
of seawater analysis. Bulletin of the Fisheries Research
Board of Canada 167: 1-310.
Sturgeon RE, JAH Desaulniers, SS Berman & DS Russel.
1982. Determination of tract metals in estuarine sediments
by graphite-furnace atomic absorption spectrometry.
Analytica Chimica Acta 134: 283-291.
Tomassetti P, P Gennaro, L Lattanzi, I Mercatali, E Persia,
D Vani & S Porrello. 2016. Benthic community response
to sediment organic enrichment by Mediterranean fish farms:
Case studies. Aquaculture 450: 262-272.
13. 235
Vol. 53, N°2, 2018
Revista de Biología Marina y Oceanografía
Received 12 April 2017 and accepted 30 July 2018
Editor: Claudia Bustos D.
Turner RE, NN Rabalais & D Justic. 2006. Predicting summer
hypoxia in the northern Gulf of Mexico: Riverine N, P, and
Si loading. Marine Pollution Bulletin 52: 139-148.
Vila M, E Garces, M Maso & J Camp. 2001. Is the distribution
of the toxic dinoflagellate Alexandrium catenella expanding
along the NW Mediterranean coast? Marine Ecology
Progress Series 222: 73-83.
Yokoyama H. 2003. Environmental quality criteria for fish
farms in Japan. Aquaculture 226: 45-56.
Yucel-Gier G, F Kucuksezgin & F Kocak. 2007. Effects of
fish farming on nutrients and benthic community structure
in the Eastern Aegean (Turkey). Aquaculture Research 38:
256-267.