2008 Annual Report
1a.Objectives (from AD-416)
1. Develop and evaluate solutions that improve efficiencies of scale and reduce water quality constraints for sustainable production. Sub-objectives are to overcome obstacles associated with managing hydraulics and harvests within large (600 m3) tanks, and control of noise, dissolved organic compounds, micro-organisms, and dissolved carbon dioxide.
2. Develop and evaluate sustainable waste management technologies that result in environmentally compatible CIAS. Sub-objectives include work on treatment processes for solids, nutrient removal from aquaculture effluents and mitigation of the impact of feed on water quality.
3. Field test selected rainbow trout germplasm resources for performance in intensive recirculating aquaculture systems.
1b.Approach (from AD-416)
The minimum bottom-center drain surface loading rate and the water inlet structure design required to produce rapid solids flushing and safe fish swimming speeds will be identified using a 600 m3 experimental tank. Studies using oxygen and pH feedback control sytems will determine whether carbon dioxide gradients will induce fish to swim out of the culture tank during a harvest event. Sound levels and frequency ranges typically produced in the CIAS environment will be identified and analyzed to determine sound levels and frequencies that can cause hearing loss, damage fish ears and result in reduced growth rates. Controlled ozone and UV systems will be used to determine the combined ozone and UV irradiation dosages required to inactivate total heterotrophic bacteria and total coliform bacteria within a CIAS. Variable feeding rates per make-up water flow rates, fish health indicators and chemical analyses of organic carbon constituent will be used to determine whether advanced oxidation techniques can reduce accumulations of organic carbon constituents that impair fish health. Carbon dioxide removal across forced-ventilated cascade columns in a marine system will be characterized and modeled as a function of air: water loading, packing height, and salinity. Molecular techniques will be used to investigate reservoirs of infection for an emerging chlamydia-like bacterium that causes respiratory disease in Artic char.
2. The solids and nutrients capture and dewatering efficiency of a new bag filter system used to treat microscreen backwash will be determined. Biological nutrient removal will be evalutated within a commercial membrane biological reactor system using seperate stages for aerobic nitrification and anoxic denitrification. In conrolled, replicated feeding studies, the 'low fish meal and high grain proportion' feeds developed by ARS nutritionists at SGPGRU will be evaluated to determine differences in the amount of solid and nutrient waste excreted in comparison with standard fish meal and fish oil based diets, and determine if these grain-based feeds impact water quality in CIAS.
3. Growth and survival data on selected rainbow trout germplasm cohorts or families provided by NCCCWA will be collected. Replicated and commercial scale intensive recirculating aquaculture systems will be operated as performance trial platforms for the evaluation of singular and mixed stocks of trout. Aquaculture systems will simulate conditions found in commercial production environments or will be modified to create enhanced challenges. Trout will be tagged to allow either individual, family or cohort identification as appropriate. Linkage with specific research objectives at the NCCCWA will be maintained.
National Program 106, Component 7, Aquaculture Production Systems.
Research activities conducted under CRIS 1930-32000-003-00D are executed as congressionally mandated through a specific cooperative agreement with The Conservation Fund’s Freshwater Institute entitled, “Development of Sustainable Land-Based Aquaculture Systems” (1930-32000-003-01G), additional details are documented in the report for this project. The ADODR is in frequent contact with the cooperator through phone calls, email, and frequent site visits in addition to receipt of written reports.
Technologies for dewatering aquaculture biosolids. Intensive aquaculture systems utilize solids capture mechanisms such as settling basins and microscreen filters to remove uneaten feed, feces, and biofloc from fish culture water. Although effective in solids removal from fish production systems, backwashing of these mechanisms produces a waste stream that still contains too much water to remain cost-competitive for most traditional manure disposal methods. The biosolids capture, nutrient retention, dewatering effectiveness, and operational complexities of three technologies: gravity thickening settlers (i.e., settling cones), belt filters, and geotextile bag filters were evaluated and compared. The belt filter produced the cleanest discharge and highest treatment efficiencies, but its operation was more complicated and time consuming than the other processes. This research identifies better waste management technologies and practices that can be implemented to improve waste capture, dewatering, and disposal at aquaculture facilities. This accomplishment aligns with the Sustainability and Environmental Compatibility of Aquaculture (Water Use and Reuse; Effluent Management Control; Environmental Sustainability) component of NP 106.
Ozonation improves fish growth, survival, and health in systems that recirculate water. Fish culture systems that recirculate water allow greater control of the rearing environment, including water temperature, by minimizing water use, and placing wastes into a concentrated and relatively small volume effluent that is easier to treat. However, suspended solids, refractory organic molecules, fine particulate matter, certain metals (e.g., copper), and microbial populations can accumulate and potentially compromise water quality and fish health in culture systems that recirculate water. Six replicated systems that were either ozonated or not-ozonated were evaluated to determine if the controlled applications of ozone would significantly improve water quality, fish performance and welfare. Results indicate that applying controlled levels of ozone to water being recirculated in a tight water reuse system (i.e., 99.7% of flow was reused) reduced suspended solids, water color, fine particulate matter, microbial populations, and copper, as well as improved rainbow trout growth, survival, and health without resorting to high system flushing rates. These findings are expected to produce healthier and more growth promoting environments under conditions where water use is restricted due to water availability or pollution abatement requirements. This accomplishment aligns with the NP 106 Aquaculture Program Components: Aquaculture Production Systems (Production Intensity) and Sustainability and Environmental Compatibility of Aquaculture (Water Use & Reuse).
5.Significant Activities that Support Special Target Populations
Technical support in aquaculture engineering, fish health and biosecurity, and trout and Arctic char culture has been provided across the Appalachian region. This work supports economic development in a region where many counties are rated as economically distressed and unemployment rates are greater than 10%. Across the Appalachian states of West Virginia, Kentucky, Virginia, Maryland and Pennsylvania, there are many natural resources that appear to represent potential development opportunities. Current production figures indicate that the Mid-Atlantic Highlands region has not yet participated in the general expansion of the aquaculture industry in the U.S.
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Wysocki, L.E., Davidson, J., Smith, M.E., Frankel, A., Ellison, W., Mazik, P.M., Popper, A.N., Bebak, J.A. 2007. Effects of aquaculture noise on hearing, growth, and disease resistance of rainbow trout Oncorhynchus mykiss. Aquaculture. 272:687-697.