Performance of J-hook and circle hook in longline fishing off Cochin, India

Abstract

J-hooks are widely used in longline fishery around the world. Circle hooks were introduced with a view to avoid turtle bycatch and deep hooking in fishes. Comparative longline fishing trials using J-hook and circle hook were carried out off Cochin in 2016. The main objective of the study was to compare the fishing performance of J-hook and circle hook and the effect of different hook shapes on species caught. Fishing trials were conducted off Cochin onboard F.V. Sagar Harita. A total of 750 hooks were deployed during the study. Indian mackerel (Rastrelliger kanagurta) of identical size was used as bait. Coryphaena hippurus and Pterotrygon violaceae were the major species caught. Results show that the percentage of hooking (individual/100 hooks) for J and circle hooks was almost same (1.47 per cent and 1.33 per cent respectively). In the case of J-hook, 27 per cent each of the fishes were hooked at throat, jaw and gut while 18 per cent fishes were foul hooked. In circle hooks 80 per cent of the fishes were hooked at jaw and 20 per cent at throat while there was no foul hooking. Percentage of escapement after hooking was 23.8 per cent in J-hook and no escapement from circle hooks.