Spatio-temporal variability in the feeding habits of anchovy and sardine: a comparison of upwelling and river-runoff driven ecosystems

Paola Rumolo¹Marco Barra^1*Angelo Bonanno²Simona Altieri³Rosalia Ferreri²Antonella Gargano²Gualtiero Basilone²Serena Gherardi¹Simona Genovese²Maria Rosa Di Cicco³Carmine Lubritto³

• ¹Consiglio Nazionale delle Ricerche - Istituto di Scienze Marine, Naples, Italy
• ²Consiglio Nazionale delle Ricerche - Istituto per lo studio degli impatti Antropici e Sostenibilità in ambiente marino, Capo Granitola - Campobello di Mazara, Italy
• ³Università degli Studi della Campania Luigi Vanvitelli, Naples, Italy

European sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) are important components of marine food webs as trophic links between primary consumers and higher trophic levels. However, local factors such as environmental conditions, human activities, coastal environmental pollution and, more generally, climate change have had a significant impact on their trophic interactions, affecting the energy flow, structure and function of marine ecosystems in which they live. Although both species are the most explored in the Mediterranean Sea, due to their commercial and ecological importance, the spatio-temporal variability in their trophic ecology is still poorly considered, especially combining life stage, years and different sites. Here we propose a spatio-temporal analysis of the trophic variability of juveniles and adults of anchovy and sardine in two different areas of central Mediterranean Sea (Tyrrhenian Sea and Strait of Sicily) in 2011, 2014, 2015 and 2017 years. We used stable isotopes ( 13 C and  15 N) approach to assess the variability in space and time of their feeding behaviour and isotopic niches (width and overlap).The data we present contributes to the understanding of food web dynamics and may be used to improve food web models, which requires an understanding of the ecological processes that control the interaction between species.