Bait, Bait Loss, and Depredation in Pelagic Longline Fisheries-A Review

This article reviews the importance of bait, bait loss, and depredation in longline fishery operations worldwide. In general, fish bait is preferred over squid due to reduced sea turtle and elasmobranch bycatch. However, there are many reports which have indicated high shark catch and deep hooking when using fish as bait. High and low hooking rates for blue shark have been reported from different fishing areas when using mackerel as bait, indicating the need for further studies on selection of appropriate baits. Conflicting results from many part of the world on the catching efficiency of different bait species on target and nontarget species indicate the need to consider area, species specific and cross taxa effect of various combinations of baits and hooks, before their adoption in commercial fishing. Baiting pattern has also been reported to affect the catch rates significantly. The review has revealed that bait loss and depredation on the hooked fish cause considerable damage to the fishery and significant economic loss. Loss rates can be significantly minimized using squids as bait while it may also incur a high catch rate of bycatch. The review has confirmed the superiority of natural baits over alternative and artificial baits during the longline fishing operations. Though an effective substitute for the natural bait has not been developed, so far, such alternatives which make use of the food and foraging behavior and the olfactory response of the fish are necessary for future development of longline fisheries.