In order to assess the level of bycatch and discard of Iranian tuna fishing vessels (Gill nets) in the IOTC competence of area, observers (port samplers) were placed in three main fishing harbors; where tuna vessels landing there. We also carried out interviews with some fishermen of the vessels. Finally the log books of the vessels were controlled and compared against the information which was collected by the port samplers. In this study we assessed the amount of catch, bycatch and discard for ten Iranian vessels. Data collection was carried out by observers who are professional in identification of species and were familiar with the Iranian tuna fishing fleets. The period of study was from 10 October to end of December 2012. The areas fished by the vessels were the north-west Indian Ocean (latitude 5-25o (N) and longitude 50-70° (E)).
Base on current study results, around 86.4% (211381 Kg) of catch comes from Tuna and Tuna like species while, around 13.6% (33273 Kg) catch belong to bycatch and discards. According to the results, target species composition mainly were Skipjack, yellow fin, Kawakawa and big eye respectively. In total the catch composition of the vessels contained 49.8% (121838 Kg) of Tuna species, 36.6% (89543 Kg) Tuna like species, 7.5% (18349 Kg) different species of sharks and 6.1% (14924 Kg) other species and discard. This is considerably important that, we have never seen any mammals or marine Turtles in catch composition as a bycatch, but we received some information from fishermen about them.
The total navigation of the vessels was 566 days, in average 56.6 days for a vessel. Because of sailing to destination, location surveys and weather conditions, there was no catches during 15 days and active fishing days for each vessels were 41.6 days in average. The average catch for each vessel was about 24.5 Tons during the navigation. Normally only one gill net installed into the Sea and investigated during a day by fishermen, so the amount of CPUE (Catch/Days) was calculated 589 Kg.
Base on received information, there are some problems on identification of species. So I.R.Iran recommend allocation funds by IOTC or other competence authorities for technical and financial assistance of the region by developing a regional plan to train the related experts and implement some researches to monitor gill net fishing activities bycatch and discard.