1a. Objectives (from AD-416)
Objective 1: Characterize genetic and phenotypic contributions of important production traits for Morone broodstock management and improvement. Sub-Objective 1A. Produce experimental hybrid striped bass families. Sub-Objective 1B. Assess the genetic basis of phenotypic variation of growth in hybrid striped bass. Sub-Objective 1C. Evaluate the performance of hybrid striped bass families under alternate stocking rates. Objective 2: Refine nutrient requirements, evaluate alternate sources of protein, and develop practical feed formulas for Morone culture. Sub-Objective 2A. Refine essential amino acid requirements of advanced juvenile hybrid striped bass using practical ingredients. Sub-Objective 2B. Improve the performance of commercial hybrid striped bass diets in which fish meal is replaced with by-products of poultry processing or a blend of plant products. Sub-Objective 2C. Develop practical feed formulas for hybrid striped bass culture. Objective 3: Develop strategies to improve production system efficiency. Sub-Objective 3A. Define stocking rate/biomass-yield relationship in a mixed suspended growth production system. Sub-Objective 3B. Compare catfish yields in a mixed suspended growth production system scaled up to ponds.
1b. Approach (from AD-416)
Identify and characterize genetic variation in commercially relevant traits of white and striped bass and implement a breeding program to develop superior hybrid striped bass parental breeding stocks. Evaluate growth performance of half-sibling families of hybrid striped bass reared communally in earthen ponds. Evaluate the performance of hybrid striped bass families under alternate stocking rates. Define requirements for hybrid striped bass for first-limiting indispensable amino acids in all plant protein diets. Evaluate amino acid supplementation for hybrid striped bass diets in which fish meal is replaced by alternative feed ingredients. Develop and evaluate in aquaria and tank culture, and validate in earthen pond culture diets for hybrid striped bass formulated with alternative feed ingredients. Evaluate the effects of stocking density, feeds and feeding strategies, and environmental conditions on survival and growth of hybrid striped bass and catfish in tanks and earthen ponds. Evaluate novel, intensive production technology in tanks and earthen ponds.
3. Progress Report
We conditioned broodstock and produced 24 half-sib sunshine bass crosses that yielded 482,000 larvae, and 13 half-sib white bass crosses that yielded 116,000 larvae. Broodstock for the next phase of spawning are being conditioned. In collaboration with the University of Arkansas at Pine Bluff, larval samples from each of the 24 half-sib families of sunshine bass and 13 half-sib families were taken just after hatching and prior to onset of feeding for analysis of the role that maternal size and age have on sunshine and white bass larvae and fingerlings. Also, ovarian condition pre- and post-hormone injection wass assessed by ultrasonography. We initiated a study to examine gene expression profiles within the testis and ovary of white bass and striped bass juveniles and broodstock. At least 10 different gene targets have been examined, and the expression levels of these genes are being correlated to gonad stage and quality as determined by histological analysis. We compared how sunshine bass, and their parent species white bass and striped bass, responded to low oxygen levels using extracellular flux technology, the first application of this technology in fish; we documented key metabolic differences between species. We completed dose-response tank trials to examine the effects of elevated water temperature on the optimum dietary protein, dietary fat, and feeding intensity in hybrid striped bass. We conducted a study to determine the optimum dietary lysine level in commercial-grade fishmeal-free diets fed to mixed families of hybrid striped bass in order to assess performance differences among strains fed high-plant protein diets. In collaboration with University of Arkansas at Pine Bluff researchers, we conducted feeding trials to assess the impact on channel catfish production of substituting standard soybean oil, soybean oil with conjugated linoleic acids, or algal n-3 fatty acid for menhaden fish oil in feed. In collaboration with ARS Trout Grains Project, Hagerman, ID, and USFWS Feed Technology Center, Bozeman, MT, scientists, we developed nutrient composition and digestibility coefficients for a variety of novel ingredients in feeding trials for hybrid striped bass and rainbow trout that are being assembled by the ARS Office of Technology Transfer for dissemination. We completed a study to quantify the growth response in earthen ponds of the channel x blue hybrid catfish to daily exposure during the summer growing season to different minimum dissolved oxygen concentrations and initiated a similar study for hybrid striped bass fingerlings. In collaboration with scientists at the ARS Natural Products Utilization Research Unit, Oxford, MS, and University of Arkansas at Pine Bluff we completed a study to evaluate the development of phytoplankton communities and common off-flavors in a biofloc technology system used for growing channel catfish and initiated a follow-on study to investigate bacterial sources of common off-flavors in this system. Quantification of the density-yield relationship for channel catfish grown in a biofloc technology production system continued, with one study completed and a follow-on study initiated.
Green, B.W., Perschbacher, P., Ludwig, G.M., Duke, S.E. 2010. Threadfin shad impacts phytoplankton and zooplankton community structures in channel catfish ponds. Aquaculture Research. 41:e524-e536.