This document summarizes research on managing a recirculating aquaculture system (RAS) to sustainably produce shrimp. The RAS was designed to conserve water, recycle nutrients, and prevent escapement of shrimp. Water quality parameters like dissolved oxygen, salinity, and ammonia were monitored daily or biweekly. Initial data showed difficulties maintaining adequate dissolved oxygen levels in the nursery and leaks in the RAS. With improvements to aeration and sealing, the RAS aims to provide a sustainable alternative to traditional aquaculture and fisheries facing declining yields.

1. Recirculating Aquaculture System Management
1, 2Jannice Newson, 1, 3Citralina Haruo, 1Cindy Yao, 1Dr. James Diana
Introduction
Aquaculture is the cultivation of animals in freshwater or saltwater
(Pillay & Kutty 2005). Aquaculture has been gaining more and more
popularity over the past 31 years as a food production system (Food and
Agriculture Organization, 2008). This has been especially significant
with an increasing global population (Hannesson 2002), a decreasing
amount of aquatic animals available for wild capture due to pollution and
overfishing.
Having a recirculating aquaculture system (RAS) offers a sustainable
option that addresses managing water quality, production yield, and
waste treatment within the system. The RAS in this study aims to raise
Litopenaeus vannamei, whiteleg shrimp, which is a widely cultivated
species (Brown 2013). For RAS to be able to compete in the shrimp
industry, it must be efficient, predictable, and stable (Verstraete et al.
2007). The RAS design works to make these goals achievable. The
results of this research will highlight the advantages and limitations of
running a RAS for food production.
Purpose
Outdoor aquaculture results in environmental degradation, including use
of sensitive coastal areas, escapement of exotic species, and discharge of
waste and nutrients (Boyd and Clay 1998). In contrast, RAS conserves
water, prevents escapement, and recycles nutrients. RAS may serve as a
sustainable solution to the seafood industry for food production. The
RAS in this study focuses on achieving sustainable and efficient
production of shrimp through microbial management of nutrients,
primarily through nitrification, which is shown below.
Design
The shrimp are first placed in the nursery, and after two weeks, they are
put into the RAS. The RAS is built from standard plywood, which is a
low cost material that would be more easily accessible than a fish tank.
The design conserves water, recycles nutrients, and prevents
escapement (Brown 2013). Water conservation is achieved through the
constant recycling of water in the RAS. The RAS in built in three tiers,
where water flows from the sump tank, through the tiered portion, and
goes through the biofilter tank before ending up back in the sump tank.
(Figure 2) The biofilter keeps ammonia out of the toxicity range
which is at or above 1 mg/L, and since nitrate does not become toxic
until 200 mg/L, nitrification is a suitable process for waste treatment
(Brown 2013).
Monitoring
In order to ensure the RAS is running properly, specific monitoring must
occur. Dissolved oxygen (DO), salinity, temperature, and pH are
monitored daily using an YSI meter. Ammonia, nitrite, and nitrate are
monitored biweekly using chemical analysis. The desired range of values
for each of these parameters is indicated in Table 1 below.
Water Quality Parameter Desired Range
Dissolved Oxygen > 5 mg/L
Temperature ~ 26 °C
pH 7.5 – 8.6
Salinity 35 ppt
Ammonia < 1 mg/L
Nitrite < 5 mg/L
Nitrate < 200 mg/L
0
5
10
15
20
25
30
35
40
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
AmountFed(g)
Days Since Shrimp Introduction
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
DissolvedOxygen(mg/L)
Days Since Shrimp Introduction
Results and Discussion
Initial data from the nursery has been compiled into Figures 2 and 3.
Difficulties with using this system include water leakage in the RAS and
maintaining DO levels in the nursery. Possible improvements include
placing an additional aerator in the nursery and using a thinner mesh
covering for the drain pipe in the nursery for easier water displacement.
With decreasing aquatic animal populations, traditional fisheries may
experience decreases in yield and increase in costs. Although outdoor
aquaculture can alleviate the concern for decreasing aquatic animal
production, its effects can contribute to destruction of wetlands
(Goldberg & Triplett 1997), invasive species due to escapement, and
algal blooms and eutrophication due to discharge of nutrients. RAS
provides an alternative that is possibly more sustainable.
Figure 1: The design of the RAS, highlighting each layer of the three tiers and the tanks
stationed on the ground. This figured is derived from ME 450 design team at University
of Michigan.
Table 1: The parameters measured
in the RAS tank and the desired
ranges for each. Values derived
from Microbial Resource
Management in Indoor
Recirculating Shrimp Aquaculture
Systems (Brown 2013).
Figure 2: The amount of Rangen #0
commercial aquaculture feed supplied
each day since the introduction of
shrimp into the RAS.
Figure 3: The earliest dissolved
oxygen level reading of each day
since the introduction of shrimp.
1University of Michigan School of Natural Resources & Environment, 2University of Missouri, 3College of Menominee Nation
I would like to thank the Dr. Taylor, Kafi Laramore-Josey, Beatriz Cañas, and Gabriel Jones (SNRE) and the Doris Duke
Foundation for this opportunity to conduct research and for their commitment to diversity, equity, and inclusion.
Addy, H., Graves, M., Rouen, K., and Solomon, J. (2016). Design of a Small Scale Aquaculture System. Retrieved from ME
450 Team 10 at Addy, H., Graves, M., Rouen, K., and Solomon, J. (2016). Design of a Small Scale Aquaculture System.
Retrieved from ME 450 Team 10 at University of Michigan.
Brown, M. N. (2013). Microbial Resource Management in Indoor Recirculating Shrimp Aquaculture Systems. (Doctoral
dissertation). Retrieved from University of Michigan.
Environmental Protection Agency. (2002). Nitrification. Inc. Washington, D.C. AWWA and Economic and Engineering Services
Food and Agriculture Organization (2008). The state of world fisheries and aquaculture 2008. Food and Agriculture
Organization (FAO) of the United Nations, Rome, Italy.
Goldburg R., Triplett T. (1997) Murky Waters: Environmental effects of aquaculture in the U.S. Environmental Defense Fund,
New York, NY, USA.
Hannesson, R. (2002). A note on unsustainable fisheries and trends in world fish catches. FAO Fisheries Report. FAO.
Pillay, T. V. R., and Kutty, M. N. (2005). Aquaculture: Principles and Practices, 2nd ed. Blackwell Publishing Ltd, Oxford, UK.
Verstraete, W., Wittelbolle, L., Heylen, K., Vanparys, B., de Vos, P., van de Wiele, T., and Boon, N. (2007). Microbial resource
management: The road to go for environmental biotechnology. Engineering in Life Sciences 7:117-126.
Acknowledgements and References
Left: Shrimp
Nursery;
Right: RAS