GENETIC IMPROVEMENT OF COLD WATER MARINE FINFISH
Location: National Cold Water Marine Aquaculture Center
Title: Performance testing and selection for commercially important traits in North American atlantic salmon
Submitted to: International Symposium on Genetics in Aquaculture
Publication Type: Abstract Only
Publication Acceptance Date: March 26, 2012
Publication Date: June 24, 2012
Citation: Wolters, W.R., Burr, G.S. 2012. Performance testing and selection for commercially important traits in North American atlantic salmon. International Symposium on Genetics in Aquaculture. 1.
Atlantic salmon, Salmo salar, aquaculture is one of the most successful global aquaculture enterprises, and has wide acceptance by American consumers. US production of Atlantic salmon is currently concentrated in Maine and Washington. The Northeastern USA, particularly the state of Maine, has suitable environmental conditions to further increase salmon production. However, regulations associated with environmental impact, mandatory aquaculture of 100% native North American salmon (in an effort to protect populations of federally endangered wild Atlantic salmon), and prevention of disease have all seriously impacted economic viability of the US salmon industry, and led the industry to consider genetic improvement of native stocks to enhance productivity of salmon farms in the Northeastern US. The initial focus of the USDA Atlantic salmon breeding program was on increasing growth rate utilizing certified North American stocks, and evaluations have been expanded to include fillet color and fillet fat in net pen reared fish, susceptibility to sea lice in net pen reared and culture tank reared fish, sexual maturity, and resistance to very low temperatures (superchill) in culture tanks. Sexual maturity is not evaluated in net pen fish as they are cultured under lights, however, sexual maturation is recorded on captive broodfish for each generation. Smolts from each year class are stocked into net pens, cultured by industry collaborators, and growth data collected at a processing plant along with tissue samples for fillet color and fat analysis. The 2003-2007 year classes have been evaluated in the breeding program. Performance of salmon from each year class is compared to a group of non-selected industry fish and a control line of non-selected wild fish. There has been significant variation in growth between fish from the breeding program, industry fish, and wild control fish, and there is additional variation due to growth differences of the different year classes, and group x year class interaction. Carcass weights of salmon from the breeding program ranged from 3.6 to 5.0 kg and were -12.6% to 24.1% different than industry fish, and 56% to 136% larger than wild control fish. Predicted responses to selection and genetic gain for carcass weight have been calculated for each generation. Fillet pigment has been measured with HPLC extraction, the a* value from a colorimeter, and VIS/NIR spectroscopy. Fillet fat has been measured with VIS/NIR spectroscopy and automated fat extraction. Susceptibility to sea lice has been evaluated with tank challenges and natural infections in sea cages. Resistance to superchill is a serious problem in parts of the salmon culture region in the northeastern US and has been measured by gradually lowering the temperature in culture tanks and measuring lethal temperature and time to death. Future plans are to evaluate markers and for disease resistance traits (IPN, sea lice), and develop a selection index for traits of economic importance as determined by industry priorities.