Study on catch composition، length frequency and catch per unit effort of Scombridae gillnet in Konarak, Sistan-Baluchestan, Iran

The main purposes were included: measure of catch composition, length frequency and catch per unit effort (CPUE) of Scombridae gillnet. Present study was conducted in coastal waters of Konarak located at Sistan-Baluchestan province, Iran during winter and spring seasons of 2016. Sampling operations with 16 times hauling using two Dhows with a length of 25 meters and a width of 7.67 m were done. Catch composition was comprised of 11 families including; Scombridae, Carangidae, Ariidae, Lethrinidea, Sphyraenidae, Lutjanidae, Haemulidae, Stromateidae, Sciaenidea and Dasyatidae with the total weight percentage of 48.46, 25.01, 7.3, 3.93, 3.53, 3.37, 3.04, 2.74, 1.44 and 0.32 % respectively. In this study, highest weights percentages of total catch in gillnet were related to Scombridae family with 30.67 % and 41.42 % in winter and spring, respectively. Also, the lowest weight percentage in winter and spring were belonging to Dasyatidae (Dasyatis bennetti) with 0.09 % and Lethrinidae (Lethrinus nebulosus) with 0.11 %, respectively. In Tuna fishes, Scombridae family with 4 species showed the highest number of species in the catch composition. The most length frequency in tuna fish were included; length range of 105-119 cm (40.7%) in Scomberomorus commerson, length range of 84-92 cm (40%) in Thunnus tonggol and length range of 58-65 cm (38%) in Euthynnus affinis, respectively. Also there was no significant difference between CPUE in winter and spring seasons (P>0.05).