Long term effects of smolt production strategy and early seawater phase rearing environment on mortality, growth, sexual maturation, and vertebra deformities in farmed Atlantic salmon (Salmo salar L.)

作者：Lars Eirik Myklatun, Thomas W.K. Fraser, PG Fjelldal, Åshild Ønvik Pedersen, Tom Hansen · 发表于：Aquaculture · 年份：2023 · DOI：10.1016/j.aquaculture.2023.739346 · 被引用次数：15 · 研究领域：Aquaculture Nutrition and Growth、Fish Ecology and Management Studies、Reproductive biology and impacts on aquatic species

The life history of Atlantic salmon is plastic and determined by factors such as daylength and temperature. In aquaculture, artificial long days during smolt production maximize growth and allows for early sea-transfer, occurring between the first summer and autumn after hatching. However, the impact of such intensive rearing strategies on the salmon's welfare is not well understood. In this study, we follow underyearling (0+) juvenile salmon through two different smolt production regimes, either dietary induced seawater tolerance (fed with SuperSmolt®) under continuous light (LLS), or light-induced seawater tolerance, where for six weeks the photoperiod was lowered to 12 h light and 12 h darkness and then increased again to continuous light (LD-LL). Next, the LD-LL and LLS salmon were distributed into indoor seawater tanks where they experienced light and temperature conditions simulating either an August (AUG) or an October (OCT) sea transfer scenario lasting 2 months, after which all fish were transferred into a sea cage and reared there until reaching harvest size (10 months). Welfare parameters were mortality, growth, vertebra deformities (radiology), and sexual maturation. LLS grew faster than LD-LL smolts up until seawater transfer, while LD-LL post-smolts grew faster during the early seawater phase, resulting in equal harvest weights. The simulated AUG transfer gave higher harvest weights than the simulated OCT transfer regardless of smolt production strategy. Mortali...