Interannual trophic behaviour of a pelagic fish predator in the western Mediterranean Sea

The exploitation of forage fish species can modify the functioning marine ecosystems potentially impacting population status predators. This may be case for western Mediterranean Sea, where a reduction in biomass two key pelagic (European anchovy Engraulis encrasicolus and European sardine Sardina pilchardus ) could produce change diet composition their main predators, which would consume alternative preys or size prey consumed. Here, we aimed to investigate potential effect Sea on trophic preferences little tunny ( Euthynnus alletteratus ), medium-sized predator that present high consumption these fish. We compared its interannual ecology by combining analysis stomach contents stable isotopes. Specifically, examined if changed habits (diet composition, size, niche) during 6-year period. found small fish, especially clupeiformes, were most important group study However, changes body relative importance recent years, probably reflecting reported area. In addition changes, an increase some demersal benthopelagic tunny, act as resource. • Trophic studied Clupeiformes group. Changes Increase