Catch performance and remaining ratio on fishing hooks for different baits used in longline fishery

Abstract

In this study, the catch performance and remaining ratio on fishing hooks of natural alive mud shrimp (Upogebia pusilla) (CCK), siliconized mud shrimp (SCK) and siliconized pellet (SP) were investigated in a longline. The trials were carried out monthly between May 2016 and April 2017 in Zeytinlikuyu district of Kıyıkislacik Village – Milas-Mugla province. The main body diameter has 0.70 mm, leader and snoods have 0.40 mm. The snood length and distance is 1.5 m and 4.0 m, respectively. 14 no straight hooks were used. Totally 150 hooks, 50 for each bait were used and each bait was replaced in 25 hooks. The individuals caught during the samplings were separated as CCK, SCK and SP, and each individual was measured as the precision of mm the total length (TL) and weighted of 0.01 g. Totally 191 individuals from seven families with 18 different species were caught. Gilthead sea bream (Sparus aurata) was the abundant species with 48.7% in all bait type, and the followed by common pandora (Pagellus erythrinus) with 10.5%, common two-banded sea bream (Diplodus vulgaris) with 9.4% and annular sea bream (Diplodus annularis) with 8.9%. Of the 191 individuals, 55% (105 individuals) were caught with CCK, 33.5% (64 individuals) with SCK and 11.5% (22 individuals) with SP. The results of the trial with 3 different bait types were shoved that that there are significant differences between the catch rates of gilthead sea bream, annular and common two-banded sea bream (χ2, P<0.05). In paired tests between bait groups (CCK-SCK, CCK-SP and SCK-SP), there were no clear differences between the sizes of the individuals (ANOVA, P>0.05). Catch per unit effort (CPUE) values of CCK, SCK and SP were calculated as 0.05 n/h, 0.03 n/h and 0.01 n/h, respectively. In the same order, yield per unit effort (YPUE) values were determined as 7.28 g/h, 4.35 g/h and 2.99 g/h. When the remaining rate of baits on the hooks were evaluated, CCK gave the lowest rate with 6.32%2.01. It is thought that SCK should be used as an alternative particularly when natural mud shrimp cannot be utilized as alive or unable to be supplied due to the cold weather conditions and time restrictions. On the other hand, it is thought that performing such studies with bait made with natural binders such as gelatine instead of silicone will be extremely important in terms of less harm to both fish and nature.