Triploid Atlantic salmon growth is negatively affected by communal ploidy rearing during seawater grow-out in tanks

• Published in: Aquaculture
• Main Authors: Taylor, John, Bozzolla, Pierre, Frenzl, Benedikt, Matthew, Chessor, Hunter, Dougie, Migaud, Herve
• Other Authors: Marine Harvest (Scotland) Ltd, Biomar Ltd, Institute of Aquaculture, University of Stirling, Machrihanish, Mowi (Scotland), orcid:0000-0003-4370-7922, orcid:0000-0002-5404-7512
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2014
• Subjects: Triploid; Growth; Family; Communal rearing; Deformity; Atlantic salmon
• Online Access: http://hdl.handle.net/1893/20571; https://doi.org/10.1016/j.aquaculture.2014.05.014; http://dspace.stir.ac.uk/bitstream/1893/20571/1/Taylor%20et%20al%202014b.pdf

Using sterile triploid salmon is of interest to fish farmers as a means to mitigate interbreeding between farmed and wild fish, prevent pre-harvest maturation and offer potential for faster growth. We investigated within the same experiment whether growth, deformity and cataract prevalence in diploid and triploid Atlantic salmon post-smolts (8 full-sib families) were influenced by isolated- or mixed-ploidy rearing during 12 months of sea water grow-out in tanks until harvest. Diploids attained significantly higher harvest weights than triploids in both treatments (+ 6.7% isolated, + 26.3% mixed). Triploid harvest weight was 29.6% lower under mixed ploidy rearing than their isolated triploid siblings. A similar effect was also observed in diploids (12% lower harvest weight). Family had a significant effect on harvest weight in both ploidy. However, family harvest weight in triploids showed a linear relationship between isolated and mixed rearing (r2 = 0.76), while a non-linear relationship was found between diploids reared in isolation or mixed populations (r2 = 0.88). Furthermore diploid family weight correlated positively with triploid weight in isolation (r2 = 0.65), but a non-significant relationship was observed under mixed rearing (r2 = 0.49). Diploids had a significantly higher condition (K) factor at harvest than triploids in both treatments, while triploid K factor was significantly reduced by mixed rearing with diploids. Triploids had a significantly higher incidence of cataract than diploids in both treatments (60.9-77.3% vs. 21.7-47.2%, severity ≥ 1). However, severity of cataract was greater in both triploids (2.43) and diploids (1.44) grown in isolation than those grown in a mixed ploidy population (triploid 2.17; diploid 1.09). Triploids had a significantly higher prevalence of visible deformity than diploids (18.1 vs. 7.2%), however, triploids grown in isolation had significantly higher prevalence than triploids under mixed rearing (30.4 vs. 5.8%). Collectively, the results provide clear evidence ...