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United States Department of Agriculture

Agricultural Research Service

2011 Annual Report

1a.Objectives (from AD-416)
This project plan uses a multi-disciplinary approach to develop and evaluate solutions for major challenges that delay expansion of controlled intensive aquaculture systems (CIAS). The objectives of this plan are:.
1)Develop and evaluate solutions that improve efficiencies of scale and reduce water quality constraints for sustainable production. .
2)Develop and evaluate sustainable waste management technologies that result in environmentally compatible controlled intensive aquaculture systems. .
3)Field test selected rainbow trout germplasm resources for performance in intensive recirculating aquaculture systems.

1b.Approach (from AD-416)
To investigate approaches for enhancing economies of scale and to reduce water quality and other environmental constraints, 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 will be conducted to determine if noise levels in the water produced by water pumping and treatment equipment affect hearing in fish and result in reduced growth. In addition, fish health will be assessed in conjunction with controlled ozone and UV treatment to determine treatment levels required to reduce bacterial load and organic carbon load; further, the utilization of bacteriophage to specifically mitigate pathogenic bacterial load in CIAS will be tested. Water quality control using new technology that facilitates carbon dioxide removal and enhances oxygen absorption will be tested and operating parameters defined. More sustainable waste management technologies for CIAS will be developed by testing several new and promising approaches to the capture and concentration of solid wastes and to their stabilization and denitrification. Further, new diets utilizing plant proteins as a substitute for fish meal proteins will be evaluated to determine if there is a differential impact on water quality of the wastes produced from feeding these diets in CIAS. Growth and survival data on selected rainbow trout germplasm cohorts or families provided by NCCCWA will be collected. Linkage with specific research objectives at the NCCCWA will be maintained.

3.Progress Report

Research on rainbow trout, arctic char, and Atlantic salmon performance, health, and welfare has been carried out in water recirculation aquaculture systems (WRAS), specifically to assess: i) water quality parameters that accumulate in WRAS operated at close to zero water exchange; ii) the effects of high vs. low dissolved carbon dioxide levels; iii) the effects of elevated nitrate nitrogen; iv) the effects of swimming speed and dissolved oxygen levels; and v) the effects of individual species strain and photoperiod manipulation. The findings of these experiments provide valuable information to producers intent on rearing any of these species to market size in freshwater WRAS. Research has also focused on state-of-the-art aquaculture system design and waste management technologies, specifically: i) the development of sidewall box low-head, high flow aerator pump to provide efficient oxygen transfer and carbon dioxide removal; ii) the effectiveness of three solids thickening processes (gravity thickening cone, geotextile filter, and belt filter) to improve waste capture and disposal; iii) the development of a novel aerated geotextile filter system for biological nutrient removal, sludge stabilization, and solids thickening; and iv) performance evaluation of membrane biological reactor technology in treating high-strength aquaculture backwash flow. These studies have assisted in increasing the efficiency of intensive fish culture in WRAS while significantly reducing the levels of phosphorus and nitrogen released into the environment through aquaculture effluent. Finally, performance and survival data for a select strain of rainbow trout developed by Troutlodge (Sumner, WA) was provided for this key industry stakeholder, and two year classes of select rainbow trout germplasm provided by NCCCWA were reared as backup at The Freshwater Institute.

The ADODR is in frequent contact with the cooperator through phone calls, email, and site visits in addition to receipt of written reports.

Last Modified: 7/1/2015
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