Supplementation of arginine, ornithine and citrulline in rainbow trout (Oncorhynchus mykiss):Effects on growth, amino acid levels in plasma and gene expression responses in liver tissue

This work was funded as a studentship between BioMar Ltd, UK and University of Aberdeen, UKPeer reviewedPostprin

Arginine, ornithine and citrulline supplementation in rainbow trout:Free amino acid dynamics and gene expression responses to bacterial infection

Acknowledgements The research was supported by a studentship to T. Clark funded between the University of Aberdeen and BioMar Ltd.Peer reviewedPostprin

The influence of the freshwater environment and the biological characteristics of Atlantic salmon smolts on their subsequent marine survival

Atlantic salmon have declined markedly in the past 20-30 years throughout their range. Much of the focus for this decline has been on increased mortality during the marine phase of the life cycle. However, marine mortality does not operate independently of factors acting in freshwater and the biological characteristics of smolts migrating to sea. Over recent decades, juvenile salmon in many rivers have grown faster and migrated to sea at a younger age, and thus typically smaller. This has shortened the generation time for many individuals, and may dampen the impact of increased marine mortality, assuming expected higher in-river survival prior to smolting is not outweighed by increased mortality of smaller smolts at sea. Over the same period, smolt run-timing across the geographic range has been occurring earlier, at a rate of almost three days per decade, on average. This has given rise to growing concerns about smolts potentially missing the optimum environmental migration “window”, the timing of which may also be changing. Contaminants and other factors operating in freshwater also impact on smolt quality with adverse consequences for their physiological readiness for life at sea. Given that managers have very limited ability to influence the broad scale factors limiting salmon survival at sea, it is vital that freshwater habitats are managed to both maximise smolt output and to minimise the impact of factors acting in freshwater which may compromise salmon once they migrate to sea.Publisher PDFPeer reviewe