Bigger is better, new COMPASS research shows that bigger sea trout smolts have higher survival!’

Effective management of anadromous Salmo trutta is challenging because long-term data on life history, phenology & survival are sparse & most stocks across the range are highly diverse & data-limited.  A recently paper published in the Journal Fish Biology looks at in-river behaviour and freshwater return rates of sea trout from two coastal river populations which was part of the EU INTERREG Va COMPASS project.  The study identifies how researchers used acoustic telemetry to tag 448 sea trout across 3 life stages, to describe the phenology, spawning behaviour & return rates of smolts, finnock & adult sea trout in 2 Irish river systems during 2018–21.  The current study indicates body size was an influential predictor of behaviour & survival across all 3 life stages. Increased body size was positively associated with marine transition success in smolts, long-term marine survival in kelts and spawning behaviour in finnock. 


This work further demonstrates the complexity of sea trout life-history dynamics and provides a comparative perspective across different age classes. An understanding of life-history variation, behaviour and survival is fundamental for the successful management and conservation of sea trout stocks.


Link to paper: