Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2013
Publication Date: 8/7/2013
Citation: Wolters, W.R., Burr, G.S., Palti, Y., Vallejo, R.L. 2013. Phenotypic and genetic variation in two North American arctic charr (Salvelinus alpinus) stocks cultured in recirculating aquaculture systems. Journal of the World Aquaculture Society. 44:476:485. Interpretive Summary: Arctic charr have a flavor many consumers feel is superior to trout and salmon, and interest in charr aquaculture is increasing with the growing trend towards consumption of quality seafood grown in sustainable production systems. Results from research studies and commercial culture have demonstrated that arctic charr have positive growth performance and marketing characteristics for culture in land based recirculating aquaculture systems. In spite of the positive attributes, expansion of arctic charr culture has not been rapid because of problems related to germplasm availability, variable growth and flesh quality, early sexual maturation, and competition with other lower cost salmonids. Development of a breeding program for North American arctic charr stocks could alleviate some of the production problems limiting expansion of arctic charr culture and provide a source of germplasm with improved production traits. Two North American arctic charr stocks were evaluated for several commercially important traits. One stock grew significantly faster than the other stock and had the best overall performance for commercial culture. Data from the study will be used to calculate breeding values on a separate group of adult broodfish and a line selected for weight gain and sexual maturity at 3 years will be developed.
Technical Abstract: Arctic charr were obtained as eggs from two North American sources, an eastern (Fraser River, Canada) and a western (Bristol Bay, Alaska) stock. Fish from each family (n=38) were pit tagged at approximately 12 months post-hatch (eastern mean+SE=247+/-13g, western mean+SE=220+/-g) and stocked communally into three replicated 7-m3 tanks at a density of 7.6+/-1.2 kg/m3. Each tank was supplied with 2 ppt salinity water from a recirculating biological filtration system. Fish were fed a commercial diet (48%P, 20%F) from automatic feeders. Fish were harvested after 37 weeks at ~24 months after hatching at a final tank density of 56.2+/-1.3 kg/m3. Mean daily water temperature was 10.4 deg C with a range of 5.9 to 12.6 deg C and mean dissolved oxygen was 12.6 mg/l with a range of 9.7 (91% of saturation) to 17.8 mg/l (149% of saturation). Individual fish were evaluated for total, carcass, and fillet weight, sex, stage of sexual maturity, gonad weight, fillet fat, and fillet color. The western stock grew faster and were significantly larger (mean+SE=1.93+/-0.03kg) (p<.0001) than the eastern stock (mean +/- SE=1.24+/-0.04kg). Heritabilities were low for all traits. Phenotypic and genetic correlations were positive, but only significant from zero for a few traits. Genetic variation was also assessed from microsatellite variability on 30 fish from each stock (eastern and western) and 32 fish from a third commercial source of unknown origin for comparison. The amount of variation detected in the western stock was higher than the eastern and commercial stocks. The eastern stock was composed from a of two founder stocks, the commercial stock was composed by three different founder stocks, and the western stock was composed by three to four founder stocks. Data will be used to calculate breeding values on a separate group of captive sibling adult broodfish and a line selected for carcass weight and maturity at 3 years will be developed.