Feeding habits during migration of the Atlantic bonito Sarda sarda (Bloch, 1793) to the Black Sea

Abstract

ABSTRACTInformation about food web dynamics is crucial for the success of ecosystem-based management. In order to collect such information, it is necessary to establish the dietary contents of species in the food chain. In this study, the diet of Atlantic bonito Sarda sarda (Bloch, 1793), one of the most important species in the Black Sea ecosystem, has been examined. The aim of this study was to investigate the prey preferences of Atlantic bonito over an eleven-year period during their feeding migration to the Black Sea. Sampling was carried out by commercial purse seine and gill nets along the Turkish Black Sea coast during migration of the Atlantic bonito from 2005 to 2016. Stomach contents were identified to the lowest possible taxonomic level. Atlantic bonito dietary composition was analyzed by fishing season, sex and size classifications. Results revealed a Vacuity Index value (V %) of 67% while 33% of individuals sampled had at least one prey species in their stomach content. Since S. sarda predominantly feed on small fish species, stomach contents contained mainly Engraulis encrasicolus, Trachurus mediterraneus, Sprattus sprattus, Mullus barbatus, Gobius niger, Merlangius merlangus, Pomatomus saltatrix, Alosa immaculata, Parablennius tentacularis and small unidentified prey items (tissue particles, … etc.). The most frequent prey item was E. encrasicolus with a percentage occurrence of 94%. In conclusion, the main prey species was determined as E. encrasicolus and statistical analyses of X2 was found significant (P < 0.005) according to year, sex and size.