THE NUTRITIONAL SPECTRUM OF SOME GOBIID SPECIES FROM THE ROMANIAN BLACK SEA COAST

Adina POPESCU; Mihaela CRETEANU; Daniela Cristina IBANESCU; Ion VASILEAN

Adina POPESCU “Dunarea de Jos” University of Galati, Domneasca Street, no. 47, Galati
Mihaela CRETEANU National Agency for Fishing and Aquaculture, Revolutiei Street, no. 17-19, Constanta
Daniela Cristina IBANESCU “Dunarea de Jos” University of Galati, Domneasca Street, no. 47, Galati
Ion VASILEAN “Dunarea de Jos” University of Galati, Domneasca Street, no. 47, Galati

Keywords: trophic spectrum, goby species, gastrointestinal tracts, index

Abstract

The main aim of this study is to analyse the trophic spectrum of four goby species (Apollonia
melanostomus, Neogobius cephalarges, Mesogobius batrachocephalus, and Gobius niger) from
the Romanian coast of the Black Sea, examining their dietary diversity, sex ratios, distribution
by area, and seasonal variation. Before analysing gastrointestinal contents and identifying
ingested organisms, the gobies were measured to determine their length classes and weighed to
establish their weight categories. The food components identified from the stomach contents
mainly consist of molluscs, which have significant trophic importance. The gobies' diet is
dominated by Dreissena polymorpha (27%), followed by Mytilaster lineatus (12%) and Mytilus
galloprovincialis (11%). The digestive tract filling index across different seasons and sexes was
also reported. For females of Apollonia melanostomus, the index was 48%, while for males it
was 52%. Females of N. cephalarges had a filling index of 56%, compared to 44% in males.
Females of Mesogobius batrachocephalus showed an index of 44%, with males at 56%. Females
of Gobius niger had an index of 33%, whereas males reached 67%. Overall, the average digestive
tract filling index is substantially higher in males (103.97) than in females (80.64).