Spatio-temporal patterns of whiting ( Merlangius merlangus ) in the Adriatic Sea under environmental forcing

Le résumé fourni par la source

Abstract Understanding how environmental factors affect species distribution is crucial for the conservation and management of marine organisms, especially in the face of global changes. Whiting ( Merlangius merlangus ) is a demersal temperate fish, considered a ‘relict species’ in the Adriatic Sea. Despite its significance to commercial fisheries in the region, the specific drivers behind its spatial and temporal patterns have not been thoroughly examined. Here, we fitted a set of Generalized Linear Mixed Effects Models to data collected in the Northern and Central Adriatic from 1999 to 2019 during the Mediterranean International Trawl Survey to investigate the potential influence of depth, seafloor temperature and bottom dissolved oxygen on the annual biomass density and spatial distribution of whiting. Our results showed that depth, and to a lesser degree temperature and oxygen, are important predictors of whiting distribution in spring-summer, with preferences for depths of ∼ 45 m, temperature of ∼ 15.4 °C and dissolved oxygen > 5.5 ml L -1 . We predicted a persistent core area of distribution in front of the Po River Delta, in the Northern Adriatic Sea, while the density progressively declined towards the Central and Southern Adriatic Sea along the Italian coast. Additionally, the temporal trend exhibited high fluctuations over the years, occurring in cycles of 3 to 4 years. Finally, by comparing the biomass density estimates obtained under optimum conditions with those derived from the actual values for each variable, our analysis revealed that temperature had a pronounced and general impact on biomass density in the northern survey area (prediction revealed a ratio of density reduction of approximatively a half), while oxygen displayed a minor and more localized influence. This work deepens the current knowledge about the ecology of whiting in the Adriatic Sea and provides support for the conservation and management of this species.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.