Predator-prey relationships are key for the balance of marine ecosystems but these relationships can be altered due to overfishing and climate change effects. This study explores the effect of overfishing of small pelagic fish in the diet of a pelagic predator, the little tunny (Euthynnus alletteratus), in the western Mediterranean Sea during the years 2012, and 2014-2017. We combined analyses of stomach contents and stable isotopic values. Results confirmed that the diet of little tunny was basically composed by small pelagic fish, mainly anchovy, Engraulis encrasicolus, and sardine, Sardina pilchardus. Some changes in the diet of this species were found, with different importance of demersal fish among years. These changes coincide with a decline of the importance of clupeiformes, mainly sardine, in the diet of little tunny. Changes on prey occurrence in the diet of little tunny may reflect the overfished status of small pelagic fish in the Northwestern Mediterranean Sea

Trabajo final presentado por Sílvia Puigarnau Benítez para el Máster en Biodiversidad de la Universitat de Barcelona (UB), realizado bajo la dirección del Dr. Joan Navarro, el Dr. Joan Giménez, y la Dra. Marta Coll del Institut de Ciències del Mar (ICM-CSIC) y de la Dra. Ana Sotomayor García.-- 15 pages, 7 figures, 6 tables

This work is a contribution to the Spanish Government PELWEB project (ES-PN-2017-CTM 2017-88939-R) and to the RyC (RYC-2015-17809) contract of J. Navarro