Barotrauma Treatment Effects on Survival Rates for some Discarded Fish by Trawl Fishery

Abstract

The discard and its losses is an important issue with the principles of sustainable and responsible fishery for researchers and the fishing technology. In this study, discard fate, which is caught and released into the sea by discarding in the Iskenderun Bay trawl fishery, was investigated. Small individuals of Nemipterus randalli (N: 340), Sparus aurata (N: 236) and Pagellus erythrinus (N: 148) with low economic value were evaluated as discard fish in the commercial trawl fishery. In order to estimate survival rates, the three fish species individuals were taken to observation tanks on the fishing vessels and waited for 30 minutes after trawl was hauled. In addition to, barotrauma treatment experiments were carried out with a formed pressure tank which produces the pressure gradient at the depth where the species is caught. Barotrauma treatment has been providing a significant contribution to increase the discard survival rate. In particular, it was observed that barotrauma treatment significantly contributed to the survival rate of the N. randalli individuals. The discard survival rates of N. randalli, S. aurata and P. erythrinus were calculated 53.4%, 65%, 68.1% with barotrauma treatment and 12.9%, 41.8%, 59% with 1 atm respectively.