Tuncay Murat Sever

New records of Bregmaceros atlanticus (Bregmacerotidae), Echiodon dentatus (Carapidae) and Nemichthys scolapaceus (Nemichthyidae) from the Aegean Sea

Three fish species, Bregmaceros atlanticus Goode et Bean, 1886 (Bregmacerotidae), Echiodon dentatus (Cuvier, 1829) (Carapidae), and Nemichthys scolopaceus Richardson, 1848 (Nemichthyidae) were recorded in the Sigacik and Kusadasi Bays (Eastern Aegean Sea, Turkey). B. atlanticus and E. dentatus constitute new records for the Turkish waters and the Aegean Sea, respectively. The finding of Nemichthys scolopaceus is the second record for the Aegean Sea.

Food and feeding habits of the Atlantic Horse Mackerel, Trachurus trachurus, from the Aegean Sea (Osteichthyes: Carangidae)

Abstract The stomach contents of the Atlantic Horse Mackerel, Trachurus trachurus (Linnaeus, 1758), were analysed to investigate the food and feeding habits of this species with respect to fish size and season. A total of 60 different prey species was found belonging to five major systematic groups, i.e. Polychaeta, Crustacea, Mollusca, Chaetognatha and Osteichthyes. Crustaceans (especially Copepoda, Euphausiacea and Mysidacea) were the most important food category by percentage of relative importance index. Teleosts were the second most important food category, while Polychaeta and Chaetognatha were occasionally seen as food. Little seasonal variation in the diet of T. trachurus was observed: copepods and mysids were the dominant prey groups in all seasons, and teleosts except in spring were the most frequent prey. However, differences in size were highlighed, with fish larger than 16.9 cm feeding on teleost larvae. At least 45 Copepoda species were identified, with Acartia clausi and Oncea media being the most significant among them by the percentage of relative importance index groups in all seasons. Copepods, euphausiids and mysids were thus the most important prey to be consumed by Trachurus trachurus in all seasons as well as by the small size classes. Moreover, teleosts constituted the main food for larger specimens.

Diet composition of the Morocco dentex: Dentex maroccanus Valenciennes, 1830 (Teleostei: Sparidae) in the central Turkish Aegean Sea

Abstract This study examined the stomach contents of 230 individuals out of 439 samples obtained from commercial fishermen between January 2013 and March 2014 from a trawler using trawl bags with a full cod-end mesh size of 44 mm. It was found that 216 samples were full and the stomach fullness index was estimated at 93.9%. The varying diet composition of the species was determined by estimating the percentage numerical composition (N%), frequency of occurrence (F%), gravimetric composition (W%) and the index of relative importance (IRI%). Diversity (Shannon index), richness (Margalef index) and similarity (Bray-Curtis index) of the catches in different seasons were calculated using the Biodiversity Professional (Version 2) software. Three major groups were identified in the catches: Crustacea, Mollusca and Teleostei. At least 17 different prey groups were identified. With regard to the diversity of consumed prey, the winter (1.204), autumn (1.079) and spring (1.000) seasons were characterized by a medium level of diversity, summer (0.699) – by a low level of diversity. However, the richness of prey does not show seasonal differences. As indicated by the Bray-Curtis index, the highest similarity between the prey groups was observed between the autumn and winter seasons, at 81.61%.

Gut contents and feeding habits of the Great Pipefish, Syngnathus acus Linnaeus, 1758, in İzmir Bay (Aegean Sea, Turkey)

Abstract A total of 112 stomachs of the Great Pipefish, Syngnathus acus Linnaeus, 1758 (56 females and 38 males), was collected in İzmir Bay (Aegean Sea) and analysed in order to determine the feeding habits. 95 specimens (85.6%) were found with prey items in their stomachs. Zooplanktonic organisms were the main food and in terms of numerical (NO%) and frequency (FO%) of occurrence, four main prey categories were determined in the gut content of this species. The most dominant group was found to be harpacticoid copepods (33.6% NO; 57.7% FO), followed by Amphipoda (22.3% NO; 38.2% FO), cypris larvae (12.8%NO; 21.9%FO) and decapod crustaceans (9.5% NO; 16.3% FO), respectively. The numbers of their occurrence indicated that there were significant differences between the seasons. Seasonal differences in the gut content were found in 9 prey groups in spring (p<0.05) and 6 in winter (p<0.05), showing that feeding is more diverse in spring than in winter. Similarly, the number of occurrences indicated that there was a significant difference in the first (p<0.05) and fourth size groups (p<0.05). However, no significant difference was found in the feeding pattern between sexes (p>0.05). Consequently, small crustaceans were the most important prey to be consumed in all seasons by all size groups of Syngnathus acus, whereas decapod crustacean larvae/eggs, larger prey items, were preferred by larger specimens.