Growth, feed conversion, sexual maturation and cataract formation in coho and Atlantic salmon post-smolts reared at different salinities in recirculating aquaculture systems for over one year

• Main Authors: Fang, Yuanchang, Emerman, Joshua, Chan, Victor, Stiller, Kevin, Brauner, Colin, Richards, Jeffrey
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: University of Toronto 2021
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/1807/107861; http://www.nrcresearchpress.com/doi/abs/10.1139/cjz-2020-0288

There is an increasing interest in defining optimal conditions to rear salmon to market size in recirculating aquaculture systems (RAS). Salinity however, as a parameter that can be potentially manipulated, has been poorly studied. To address this knowledge gap, we reared coho (Oncorhynchus kisutch Walbaum, 1792) and Atlantic (Salmo salar Linnaeus, 1758) salmon from smolt to market size over ~460 days at five different salinities (0, 5, 10, 20 and 30 ppt) and examined their growth performance. We found that both species reared at intermediate salinities (5-10 ppt) started to show significantly larger body mass than fish reared either in freshwater or full-strength seawater at around day 250-300. These growth-enhancing effects were maintained until day 460. The higher growth in Atlantic salmon at intermediate salinities was associated with reduced economic feed conversion ratio, but this was not observed in coho salmon. The all-female coho salmon showed no incidence of sexual maturation and negligible cataract formation, while the mixed-sex Atlantic salmon showed high levels of sexual maturation (up to 50%) and presence of cataracts (up to 60%). Our results indicate that all-female coho salmon may be better suited to RAS than Atlantic salmon in some aspects. However, in both species, long-term rearing at intermediate salinities improves growth in RAS. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.