Early enrichment effects on brain development in hatchery-reared Atlantic salmon (Salmo salar): no evidence for a critical period

Joacim Näslund, Kim Aarestrup, Søren T. Thomassen, Jörgen I. Johnsson

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In hatcheries, fish are normally reared in barren environments, which have been reported to affect their phenotypic development compared with wild conspecifics. In this study, Atlantic salmon (Salmo salar) alevins were reared in conventional barren hatchery trays or in either of two types of structurally enriched trays. We show that increased structural complexity during early rearing increased brain size in all investigated brain substructures. However, these effects disappeared over time after transfer to barren tanks for external feeding. Parallel to the hatchery study, a group of salmon parr was released into nature and recaptured at smoltification. These stream-reared smolts developed smaller brains than the hatchery reared smolts, irrespective of initial enrichment treatment. These novel findings do not support the hypothesis that
there is a critical early period determining the brain growth trajectory. In contrast, our results indicate that brain growth is plastic in relation to environment. In addition, we show allometric growth in brain substructures over juvenile development, which suggests that comparisons between groups of different body size should be made with caution. These results can aid
the development of ecologically sound rearing methods for conservational fish-stocking programs
Original languageEnglish
JournalCanadian Journal of Fisheries and Aquatic Sciences
Volume69
Issue number9
Pages (from-to)1481-1490
ISSN0706-652X
DOIs
Publication statusPublished - 2012

Fingerprint Dive into the research topics of 'Early enrichment effects on brain development in hatchery-reared Atlantic salmon (Salmo salar): no evidence for a critical period'. Together they form a unique fingerprint.

Cite this