Survey of night and day trawler fishing in the northern waters of Oman Sea (Sistan and Baluchestan Province)

In this study, sampling of commercial vessels of Afsoon 1 was carried out in July 2020, at a distance of more than 10 miles in longitude24 50 to 24 60and latitude 61 03 to 61 05. At the time of the study, trawl fishing 13 times was done at different times (8 times during the day and 5 times at night). The total catch during the study period was 12306 kg and 8720 kg were caught during the day (about 71%) and 3586 kg at night (about 29%). The average catch per fishing effort (catch per hour) of the target species was 201 kg (67%) during the day and 63 kg (33%) at night, and the average catch per fishing effort (catch per hour) discard species were 71 kg (28%) during the day and 100 kg (59%) at night (P <0.05). The study of target fish catch in depth different showed that with increasing depth, the target fish catch increased and the highest percentage of target fish catch was seen at depths of more than 120 meters (P <0.05). The rate of discard fish species was about 40% and its rate was more at night than day time and the discard fish species CPUE rate of trawlers showed in the night more than daylight time (P <0.05). In general, it seems that discard fish species ratio of trawler in the night hours is more than during the day and this rate at depths less than 100 meters is higher.