Determining fishing compositions and selectivity of bottom long line kits used in North Aegean sea

In this study, catch compositions and selectivity of bottom longlines operational problems including bait and hook selection have been investigated. In addition CPUE, bycatch and discard rates have been attempted.In order to determine, technical specificications and charactaristics of longline gears that are extensively used in Northern Aegean survey study has been conducted with 426 fishermen in 37 different locations. It was determined that the fisherman in North Aegean Sea use four different longline types (Type 1 Xiphias spp., Type 2 Merluccius spp., Type 3 and Type 4 of longline is for different Sparidae species). For third type longline has 0,80 mm main line and 0,40 mm. snood, whereas for fourth type the main line 1,20 mm. snood, 0,80 mm. Results of preliminary surveys have been used to select the tipe of longlines and study locations. Based on survey data, the present study has been carried out in North Aegean Sea, Çanakkale, Gallipoli, during May 2011-June 2012 at the 0-500 m. A total of 20 operations have been performed with using 60 longline baskets equipment with a total 12000 hooks and 60000 meter monoflament lines.Of the 1360 fish caught and 722 of the were caught with third type of gear and 638 fish were caught with fourth type of gear. With regard the baits used, cuttle fish had the highest cacth ratio (42,61) in third type gears, whereas sardine had highest cath ratio (33,07%) in the fourth type gear. The catch ratio of cross and plain hooks were 389 and 333 fish respectively. The type of hook had significant effect on fish species.48,16% (655 fish) of the fish caught with longlines were the target species. Merluccius merluccius was the most abundant fish represented by 16,32% (222 individuals) followed by Physsis blennoides 7,28% (99 individuals). In terms of bycatch, Astropecten spp. was the most abundaned species represented by 15,59% (212 individuals) followed by S. cabrilla, represented by 8,31% (113 individuals). Lenght- weight reletationships as well as horizontal mouth width- lenght and vertical mouth gape-lenght correlations have been estimated for Merluccius merluccius, for Serranus cabrilla, for Physsis blennoides.Key words: Long line, North Aegean, Selectivity, Catch Composition, Çanakkale