OPEN ACCESS plSSN : 0374-8111 | elSSN : 2287-8815
OPEN ACCESS plSSN : 0374-8111elSSN : 2287-8815
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kfas, vol. 55, no. 6, pp.894-902, December, 2022 DOI. https://doi.org/10.5657/KFAS.2022.0894

Effects of Photoperiods and Body Size on the Off-season Smolt Production
of Atlantic Salmon Salmo salar in a Recirculating Aquaculture
System

김유희·김병기*
강원도립대학교 스마트해양양식과

  • ABSTRACT

    This study investigated the effects of photoperiod (NL 12L:12D and LL 24L:0D) and body sizes (30 g and 50 g) on parr-smolt transformation, post-smolt growth and blood properties in the off-season parr-smolt stage of Atlantic salmon reared in a recirculating aquaculture system (RAS). Potential off-season salmon smolt were reared in a freshwater RAS for 80 days and then all experimental fish were transferred to seawater. In both LL groups (LL-30 and LL-50), we recorded and increase in specific growth rate and reduction in feed conversion, although there were no significant difference in body size. The values of osmolality, and serum Na+, Cl- and cortisol concentrations in the LL groups were maintained at lower levels than in NL group fish, and LL group fish were observed to recover to the pre-seawater adaptation state more rapidly than those in the NL group. ID chips were inserted in all smolts reared in freshwater. These fish were subsequently transferred to full-strength seawater and thereafter individual growth rates were monitored for 120 days. The results indicated that compared with smolt reared under natural photoperiodic condition, 24 h lighting in freshwater contributed to enhancing post-smolt specific growth rate in seawater.

  • Keyword

    Atlantic salmon, Smoltification, Osmolality