From west to east: Heterogeneity in the life history traits of a small pelagic fish (Sardina pilchardus) throughout the Mediterranean

Small pelagic fish are key elements of marine trophic networks and great importance to the total landing species. Over last decades, a decrease in biomass catches European sardine has been described, especially Mediterranean Sea, as an indication drop stock condition. Multiple causes, including direct indirect anthropogenic factors, seem affect this ecologically economically important To address issue, it is identify current variability status understand strategies for energy allocation, which intimately related reproductive potential recruitment. We analyzed somatic condition through tissue mesenteric lipid measurements, relative ( Kn ) hepatosomatic HSI indices, with gonadosomatic index GSI four subareas (Northern Alboran, Northern Spain, Adriatic, Aegean Sea) outgroup from Atlantic. The analyses were performed within gonadal development cycle since translocation reproduction may mask state actual reserves comparison. results revealed marked differences health among subareas, highlighting low Spain sardines throughout annual cycle. uniform Adriatic suggests that resource availability modulates strategy locality, would have high dependence on immediate reserves, not behaving strict capital breeders. Moreover, similarities between Alboran Atlantic stocks discussed, replenishment latter after compared stocks. was fastest reach its maximum spawning, presenting values developing actively spawning period, but greatest recovery at regressing phase, coinciding peak productivity. Finally, role liver storage considering heterogeneity, potentially indicating feeding activity. Given divergences stocks, we propose concrete measures managing (i.e., need adapting close seasons), could be applied other species similar contexts.