Controlled Ghost Fishing: Effects of Soaking Times and Mesh Sizes on Catchability in Trammel Net Fisheries

Trammel nets are used with extended soaking times to increase the catching efficiency for demersal fish in commercial fishing. Long soaking time causes deterioration or damage to species caught in the first days. Effects of soaking time were investigated with 36-mm, 42-mm, and 46-mm mesh sizes soaked over 1, 3, 5, and 7 days on target, non-target, and other species. Only 26.3% (293 individual fish) of 1113 individual fish were not damaged of the target species. Total weight of non-damaged individuals was 247.6 kg, of which 150.6 kg (60.8%) was the target species. Critically endangered and endangered Chondrichthyes species were negatively affected by soaking time and mesh size. Current and previous regulations did not restrict soaking time or mesh size of trammel-net fisheries in T & uuml;rkiye. Extended soaking times of trammel nets may cause more negative ecosystem effects than ghost fishing. Consequently, 42-mm mesh-size trammel nets soaked for 1 day should be used by fishers. If used for more than 1 day, 42-mm or 46-mm mesh sizes should be used.