Gillnet selectivity experiments in Bahrain waters on the Spanish mackerel, Scomberomorus commerson (Lacepede)fishery

The selectivity of 9.5, 11.4, and 14.0 cm mesh size gillnet was tested experimentally in the Bahrain waters. A total of 12 hauls were conducted during the period from 5^th June to 27^th December 1999. Significant differences in the first girth indicted smaller (mean fork length 75.2 SD ± 5.0) and mainly immature Spanish mackerel were caught by 9.5 mesh panels. Milk Shark Rizoprionodon acutus numbers exceeded the Spanish mackerel numbers, and made up 85 % of the total bycatch. Most of these sharks were caught in the 9.5 mesh panel. The importance of the shark issue in the management of the Spanish mackerel fishery was highlighted by the present study. It is suggested that future management of the Spanish mackerel fishery should take into the consideration the conservation of the shark stocks. It is also suggested that better management results can be achieved by increasing the lower limit of mesh size to 14.0cm. This study provides a preliminary list of the drift gillnet bycatch species. This is probably the first attempt to provide information on drift gillnet by catch in the Arabian Gulf.