Document Type : (original research)
Fisheries Department, Faculty of Marine Science, Chabahar Maritime University, Chabahar, Iran.
Fisheries Department, Faculty of Marine Sciences, Chabahar Maritime University, Chabahar, Iran
In the present study, some biological characteristics of Frigate tuna Auxis thazard (Lacepede, 1800) species caught with drift gillnets in chabahar fishing ports from October 2019 to March 2020, were studied and measured. Fishing operations were performed by multifilament surface drift gillnets with hanging ratio 50% and mesh size 70, 79 and 101 mm from knot to opposite knot (STR). In total, 299 fish samples were bioassayed that the Mean±SD of fork length in autumn and winter 38.02±4.94 cm and 37.58±4.84 cm and in total sampling duration 37.80±4.89 cm were obtained. Length range of caught fishes was from 30 to 50 cm, that the length ranges of 37-36 and 35-34 cm had the highest relative frequency with 21.74% and 18.39%, respectively. The exponential equation of fork length and weight was calculated as W= 0.0102 FL3.1077and logarithmic data exhibited the exponent value of b>3, showed that A. thazard has positive allometric growth. Also in total fish, between fork length and weight and fork length and girth were a high significant correlation (P< 0.01).According to the Lm50 of A. thazard reported in previous research 29.7 cm, the findings of the present study showed that A. thazard caught on the shores of Chabahar have a standard size, which is very effective in managing successful fishing of this species in the region.