Influence of Colors on the Catching Performance of Artificial Lures of Multiple Troll Line in Bongao Waters, Tawi-Tawi, Philippines

Abstract

Improving the efficiency of fishing gears to catch species and sizes selectively and to catch more fish with less fishing efforts are essential objectives in fisheries research. This study utilized a small-scale multiple troll line, using two different artificial lures, i.e., green and blue, to determine the color lure preference of fish catch, catch composition, relative abundance, and catch per unit effort. In addition, the length-weight relationships of the caught species were also investigated. The study was conducted in the Bongao waters, Tawi-Tawi, Philippines, through fishing samplings using two separate motorized boats with two gears. A total of 1,032 fishes were caught by multiple troll line, which identified nine species with relative abundance: frigate tuna juvenile Auxis thazard (37.11%), bullet tuna Auxis rochei (24.90%), eastern little tuna Euthynnus affinis (15.99%), bigeye scad Selar crumenopthalmus (15.21%), yellowfin tuna Thunnus albacares (3.01%), common dolphin fish Coryphaena hippurus (1.75%), double-lined mackerel Grammatorcynus bilineatus (1.16%), shortfin scad Decapterus macrosoma (0.58%), and skipjack tuna Katsuwonus pelamis (0.29%). There were 677 fishes (65.89%) and 355 fishes (34.41%) lured by green and blue artificial lures, respectively. Most of the caught species had a size distribution ranging from 21.5 cm to 30.5 cm for both lure colors. The slopes (b) of the length-weight relationships of the caught fishes ranged between 1.5473 (skipjack tuna) and 3.305 (bullet tuna). In terms of catch per unit effort (CPUE) for all the species caught, the multiple troll line with the green lure had the highest mean CPUE with 0.63±0.12 kg/hr, while the blue lure had a mean CPUE of 0.35±0.7 kg/hr, although there was no significant difference (p > 0.05). This study suggests that multiple troll lines with either green or blue lures are effective small-scale fishing gear to catch small tunas and tuna-like, especially frigate tuna, bullet tuna, and eastern little tuna.