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United States Department of Agriculture

Agricultural Research Service

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Research Project: Improving the Sustainability of Land-Based Closed-Containment Systems for Salmonid Food Fish Production

Location: Cool and Cold Water Aquaculture Research

2012 Annual Report


1a.Objectives (from AD-416):
1: Identify criteria to optimize the performance, health, welfare and consumer value of Atlantic salmon and other salmonids grown to food-size in intensive, land-based, closed-containment systems. • 1.1 Determine effects of high (20 mg/L) and low (10 mg/L) dissolved carbon dioxide concentrations on Atlantic salmon performance, health, and welfare during growout in freshwater RAS. • 1.2 Determine effects of strain and photoperiod manipulation (to produce smoltification) in a 2 x 2 factorial study on Atlantic salmon growth, processing attributes, and sexual maturity to 24 months post-hatch in freshwater RAS • 1.3 A comparison of rainbow trout performance and welfare in semi-closed (i.e., makeup freshwater supplied only to replace backwash flows) versus closed (i.e., freshwater backwash collected and reclaimed using MBR treatment) RAS operated with ozonation. • 1.4 Determine effects of swimming speed (2 body length/sec versus < 0.5 BL/sec) and dissolved oxygen concentration (70% versus 100% saturation) on rainbow trout performance and welfare.

2: Improve the effectiveness, energy efficiency, and economics of water reuse and waste treatment technologies and practices. This will include developing technologies to minimize waste and reclaim water, protein, and/or energy to improve the economic and environmental sustainability of closed-containment systems.

• 2.1 Economic evaluation and life cycle assessment of land-based closed-containment systems for production of food-size Atlantic salmon and rainbow trout. • 2.2 Development of low-head and high-volume gas transfer processes to improve the energy efficiency of RAS. • 2.3 Improve technologies and practices that counter the effects of fish pathogens, and reduce the need for chemotherapeutic and antibiotic use within closed-containment production systems. • 2.4 Optimize cell age within MBR systems to maximize metals removal and protein content of waste mixed liquor suspended solids.

3: Conduct production trials of fish and feeds developed through ARS collaborations.

• 3.1 Compare the effects of grain versus fishmeal-based diets on rainbow trout performance and welfare, as well as water quality, water treatment process performance, and waste production rates in RAS operated at low flushing rates. • 3.2 Field test selected rainbow trout (NCCCWA, Leetown, WV) or Atlantic salmon (NCWMAC, Franklin, ME) germplasm resources for performance in intensive recirculating aquaculture systems.


1b.Approach (from AD-416):
Research at The Conservation Fund’s Freshwater Institute focuses on developing and improving technologies to enhance the sustainability and reduce the environmental impact of the modern fish farming industry. To this end, the proposed projects listed in this plan will continue our work in pioneering land-based, closed containment water recirculation systems that are biosecure, have an easily controlled rearing environment, produce healthy and optimally performing fish, and produce manageable effluent for significant reduction in waste discharge. Specifically, our proposed research will investigate, among other things, the biological and economic feasibility of raising Atlantic salmon to market size in freshwater recirculation systems (as opposed to coastal net-pens); the potential for raising rainbow trout in semi-closed or closed water recirculation systems to further reduce the amount of influent water and point source discharge required for these systems; the health and welfare of salmon and trout in relation to dissolved oxygen and carbon dioxide levels, swimming speed in circular tanks, soy-based feeds, and water ozonation in low-exchange systems; and the potential for greater energy efficiency in water recirculation systems through improved low-lift pumping and gas transfer processes. In addition, our experimental systems will continue to serve as field testing sites for alternative-protein feeds and for salmon and trout strains selected through genetic improvement programs at other USDA facilities. The investigations proposed in this plan will build on the findings of previous years of USDA-funded research to develop a sustainable, environmentally responsible, and economically viable aquaculture industry in the United States.

1. Identify criteria to optimize the performance, health, welfare and consumer value of Atlantic salmon and other salmonids grown to food-size in intensive, land-based, closed-containment systems.

2. Improve the effectiveness, energy efficiency, and economics of water reuse and waste treatment technologies and practices. This will include developing technologies to minimize waste and reclaim water, protein, and/or energy to improve the economic and environmental sustainability of closed-containment systems.

3. Conduct production trials of fish and feeds developed through ARS collaborations.


3.Progress Report:
The overall goal of this project is to develop and improve technologies that enhance the sustainability and reduce the environmental impacts of the modern fish farming industry. Progress was made in several areas.

Research on Atlantic salmon performance, health, and welfare, plus system water quality, was carried out in replicated water recirculating systems that were operated at either high makeup water (2.5% flow exchange) or low makeup water (0.25% flow exchange) flushing rates. This work has provided valuable information to producers intent on rearing Atlantic salmon in closed-containment systems up to market size in fresh water.

A sidewall box containing a forced-ventilated cascade column and low-head axial flow pump was developed and found to provide a more cost and energy effective method for adding oxygen to and removing carbon dioxide from water recirculated back into the fish culture tank. As a result of this positive analysis, this technology can be integrated into the design of much larger recirculating aquaculture systems to improve gas control, provide culture tank rotation, and reduce total power requirements and the carbon footprint of these systems.

We compared the effects of grain versus fishmeal-based diets on rainbow trout performance and welfare, as well as water quality, water treatment process performance, and waste production rates in water recirculating systems operated at low flushing rates.

Selected Atlantic salmon (NCWMAC, Franklin, ME) germplasm resources, one group diploid and the other triploid, were received as eyed eggs, hatched, and cultured to parr. After smoltification, these diploid and triploid salmon will be evaluated during growout within intensive water recirculating systems.

We employed 454 pyrosequencing toward characterizing intestinal microflora of rainbow trout fed grain- or fishmeal-based diets and raised at high or low densities. The novel discovery of a core intestinal microbiome that appears resistant to changes in diet and density will assist aquaculture nutritionists in formulating new diets that are both environmentally sustainable and fish performance-enhancing. We evaluated the effects of chronically elevated nitrate nitrogen on rainbow trout performance, health, and welfare. Findings are critically important in establishing boundary design criteria for rearing system water quality in tightly closed recirculating systems.


4.Accomplishments
1. New cascade column and low-head pump combination reduces the energy requirement for producing fish in water reuse systems. A sidewall box containing a forced-ventilated cascade column and low-head axial flow pump was developed by ARS researchers at Leetown, West Virginia to provide a new high water flow and low lift method of gas exchange just outside of the culture tank. Water and air flow rates were measured, plus energy consumption, dissolved oxygen and carbon dioxide transfer rates and efficiencies. The novel application was found to reduce electric and oxygen costs by as much as 50% compared to more conventional partial water reuse technology. The sidewall box cascade column and low-head pump can be integrated into the design of much larger recirculating aquaculture systems to improve gas control, provide culture tank rotation, and reduce total power requirements and the carbon footprint of these systems.

2. Atlantic salmon health and performance unaffected by relatively low system flushing rates. Atlantic salmon were cultured by ARS researchers at Leetown, West Virginia for 6 months in replicated water recirculating systems operated with either high water flushing (97.5% of system flow recirculated) or low water flushing (99.75% of system flow recirculated) to observe differences in fish performance, health and welfare. By study’s end, no significant differences were determined in growth, survival, and other measured fish health outcomes even though the low water flushing treatment operated with 10-times less water use. Although significant differences in a variety of water quality parameters were noted, none of these parameters was outside acceptable ranges for raising salmonids. The results of this study illustrate that Atlantic salmon perform comparatively well even in water recirculating systems that receive almost no water flushing and demonstrate that farmers with limited water resources can still remain competitive in terms of salmon production.


Review Publications
Davidson III, J.W., Good, C.M., Welsh, C., Summerfelt, S.T. 2011. Abnormal swimming behavior and increased deformities in rainbow trout Oncorhynchus mykiss cultured in low exchange water recirculation aquaculture systems. Aquacultural Engineering. 45(3):109-117.

Penderson, L., Good, C., Penderson, P. 2012. Low-dose hydrogen peroxide application in closed recirculating aquaculture systems. North American Journal of Aquaculture. 74(1):100-106.

Burr, G.S., Wolters, W.R., Schrader, K., Summerfelt, S. 2012. Impact of depuration of earthy-musty off-flavors on fillet quality of Atlantic salmon, Salmo salar, cultured in a recirculating system. Aquacultural Engineering. 50:28-36.

Last Modified: 11/27/2014
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