Contemporary ocean warming and freshwater conditions contribute to delay the completion of maturation in Atlantic salmon
Otero, Jaime; Jensen, Arne J.; L’Abée-Lund, Jan Henning; Stenseth, Nils Christian; Storvik, Geir; Vøllestad, Leif Asbjørn
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http://hdl.handle.net/11250/102590Utgivelsesdato
2010Metadata
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The completion of maturation in Atlantic salmon (Salmo salar) depends on
environmental conditions that affect both feeding opportunities and growth, which
would provide sufficient lipid stores for reproduction. However, if the level of energy
reserves of a given fish is below a certain genetic threshold at a critical decision time
further gonadal development is arrested and fully maturation postponed. This individual
development pattern suggests that the proportion of fish maturing at a given sea age
could vary from year to year according to the feeding opportunities in the oceanic
migratory habitat, and the growth rate during freshwater residence that might be
associated with growth at sea. In this study we show that sea age at maturity of adults
caught in multiple Norwegian rivers has increased with increasing sea surface
temperature (SST) experienced by the fish in autumn months during their first year at
sea. Furthermore, freshwater conditions measured by river discharge during summer
months one year ahead of seaward migration is positively related with increasing sea
age at maturity. This result is discussed within the broad changes occurring in the
North-east Atlantic pelagic food web mostly related with the current ocean warming,
and river conditions influencing growth rates.