Diet composition of bluefish Pomatomus saltatrix (Linnaeus, 1766) in the Sea of Marmara

Abstract

In this study, diet composition of bluefish Pomatomus saltatrix (Linnaeus, 1766) was investigated. A total of 512 bluefish samples were monthly collected from commercial fishing boats operating in the Sea of Marmara between January and December 2014. It was determined that the total length distribution of the samples varied between 12.3-47.3 cm. 367 of them (71.67%) were found to be the full of the stomach. The nutritional composition of stomach contents only two main prey groups (teleostei and crustacean) were identified. In evaluation, relative importance indexes (IRI) food groups were calculated. According to the relative importance index (IRI=91.8%) anchovy (Engraulis encrasicolus) has been found to be the most preferred food group. The number of individuals whose stomachs were found to be full was low in the winter months; it started to rise with spring and reached the highest level in the autumn months. It was determined that the increase in the total number of stomachs occurred between August and October in relation to the reproductive period. It was found that stomach fullness rates significantly relationship between sex and seasons (p<0.01).