Investigation of the Effects of Hook Size and Bait Type on the Catch of Whiting, Merlangius merlangus (Linnaeus, 1758) (Gadidae) in Bottom Longline Fisheries of the Black Sea

Abstract

This study was carried out along the Ünye coasts of the South-eastern Black Sea (Turkey), in orderto investigate the effects of hook size and bait type on the catch of whiting, Merlangius merlangus(Linnaeus, 1758) (Gadidae) in the bottom longline fisheries. For this, a set of bottom longline witha total of a hundred hooks, including 20 from each hook number 2, 4, 6, 8 and 10, was tested in atotal of 24 trials twice a month between March 2017 and February 2018. Each hook type was baitedwith squid, horse mackerel, chicken breast and whiting. During the study, a total of 373 whitingwere caught. Most of the whiting catch was obtained with the hook no 2. With the reduction inhook size, both the amount of catch and the size of the fish caught decreased. Most whiting werecaught by the hooks baited with squid. This was followed by the hooks baited with horse mackerel,chicken breast and whiting, respectively. This result shows that hook size no 2 or larger should beused for catching whiting when using bottom longline in the Ünye coasts of the South-easternBlack Sea. Howev-er, considering the bait types used in this study, it is recommended to use squidas bait. If squid is thought to increase the cost of fishing, alternatively horse mackerel or chickenbreast can also be used as bait