Bioecological characteristics of some fish species that are caught and have high economic importance in dalyans in the bosphorus

Dalyan fishing is a fishing method operating as sustainable systems established for seasonal fishing for approximately two months in Istanbul after the end of the industrial fishing season. During the two-month fishing season, 16 fish species from 12 families were fished in the fisheries in the Bosphorus. Hunted species; Bluefish (Pomatomus saltatrix), horse mackerel (Trachurus mediterraneus), mullet (Mugil cephalus), sardine (Sardina pilchardus), tabby (Mullus surmuletus), garfish (Belone belone), butt (Spicara smaris), silver (Atherina sp.), bream (Diplodus vulgaris), anchovy (Engraulis ecnrasicolus), thrush (Sciaena umbra), sprat (Sprattus sprattus), minekop (Umbrina cirrosa), sea bass (Dicentrarchus labrax), corn (Lithognathus mormyrus) and mackerel (Scomber scomber) taken. Height, weight and gonad weights of horse mackerel (Trachurus mediterraneus) and bluefish (Pomatomus saltatrix) caught, which are of high economic importance, were checked and average height (length), average weight, sex distribution, condition factor and height-weight relationship were determined. In this thesis study carried out in 2020 and 2022, Bağlaraltı Dalyan and Filburnu Dalyan, which are among the hunting areas, were determined as sampling areas. 280 bluefish (Pomatomus saltatrix) and 280 horse mackerel (Trachurus mediterraneus) samples were taken from each hunting area and examined bioecologically. At the end of the investigations, the highest average weight of 121,3 g for the bluefish (Pomatomus saltatrix) was recorded in the samples taken from Bağlaraltı Dalyan in 2022. The highest average height was measured in Filburnu Dalyan in 2020 with 23,65 cm. The highest average weight of 42,82 g for horse mackerel (Trachurus -mediterraneus) was found in Filburnu Dalyan in the samples taken in 2022. The highest average height of 16,76 cm was determined among the samples taken from Filburnu Dalyan in 2022. Key words: Dalyan, catch composition, length-weight relationship, Bosphorus.