Investigation of different hook models in bottom long-line in terms of catching efficiency and catch compositiob
Project no. 1059 · Status: Kapanmış · 2018
Summary
In recent years, the use of circular hook models instead of J hook traditionally used in scientific studies on bottom longline fishery has been investigated. In the study, circularshaped C (Owner Chino 50355-1) and K (Owner Mutu 50660-1) hook models used as an alternative to traditional J-shaped hook (Mustad 2315 DT-14), were compared in terms of catch composition, catch rate, survival of the fish caught and where the hook was caught. The relative performance of circle (C and K shaped) and traditional J-style hooks was tested during 21 valid pelagic longline fishing operations held in Edremit Bay Artificial Reef Area between August.2018 and August.2020. A total of 2100 hooks were used equally C-style, Kstyle, and J-style hooks consecutively. Captured fish were identified, total and fork lengths were measured, weighed, the time of haul-back, and hook type as well as whether the fish caught were alive or not according to the needle type and the places of catching were recorded. A total of 534 fish were caught belonging to 27 species during the samplings. CPUE are calculated as 23.0 fish per 100 hook for J-shaped needles, 26.1 fish per 100 hook for C-shaped hook and 27.1 fish per 100 hook for K-shaped hook. A statistically significant difference was not found between hook models p > 0.05). The highest CPUE value in the Jshaped hook model is Serranus scriba with 2.7 fish per 100 hooks, and the highest CPUE value in the C-shaped hook model is Diplodus vulgaris with 4.7 fish per 100 hooks and in the K shaped hook model, the highest CPUE value belongs to Diplodus vulgaris with 4.4 fish per 100 hooks. It was determined that fish caught with C and K-shaped hook models remained alive at a higher rate compared to J-shaped hook models (p<0.05). The use of circular-shaped hook models should be encouraged in longline fishing in Turkey in order to increase the fishing efficiency and the survival rate of discarded species.