1Nagasaki Prefectural Institute of Fisheries, Taira, Nagasaki 851-2213, 2Research and Development Department, Nichimo Co., Ltd., Shimonoseki, Yamaguchi 750-1136, 3Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Bunkyo, Nagasaki 852-8521, Japan
A 55-W underwater discharge lamp was set on one side of the leader-net of a set-net off Tsushima, Nagasaki to lure migrating fish during the nighttime. The lamp was turned off by a timer in the morning to direct fish into the set-net prior to hauling. The purpose was to improve the catch efficiency of set-nets using low-power underwater lighting. Illuminated and non-illuminated fishing experiments were conducted repeatedly from 2007 to 2009. When the light was turned on, the daily catch amount was significantly larger than that of the conventional operation without lighting (p<0.05). The round herring Etrumeus teres was the dominant catch in 2007, the swordtip squid Photololigo edulis and yellowtails Seriola quinqueradiata and S. dumerili in 2008, and the chub mackerel Scomber japonicus in 2009. Catches of these dominant species were significantly higher with illumination (p<0.05). Thus, use of the low-power underwater light improved the catch performance of the set-net.