Silver spoons in the rough: can environmental enrichment improve survival of hatchery Atlantic salmon Salmo salar in the wild?

摘要: This study tested the ‘silver spoon’ hypothesis which posits that individuals develop under favourable conditions should enjoy a fitness advantage later in life because they are more likely to recognize and settle high-quality habitats. Atlantic salmon Salmo salar of two age classes (0+ 1+ years) were reared environmentally enriched or standard hatchery tanks for short period (c. 10 weeks), then released into natural river sampled on repeated occasions test silver-spoon effects. Compared with controls, fish had 6·4% higher recapture rate settled velocity habitats when stocked as 0+ year fry, but not parr. The opportunity selection was generally than also fish. Selection favoured high condition factor, extensive fat reserves longer average pectoral fins both small body size large releases. Stomach analysis showed ate more, adapted quicker prey controls. These results provide support effects indicate enrichment can improve post-release performance conservation programmes, seemingly only if kept captivity too long.