The use of artificial illumination to reduce Pacific halibut (Hippoglossus stenolepis) bycatch for a high-rise bottom trawl in the U.S. West Coast groundfish fishery

Abstract

In the last decade, there has been increasing interest in the use of artificial illumination as a bycatch reduction device. In the U.S. West Coast groundfish bottom trawl fishery, research has found that the addition of green light-emitting diode (LED) lights to the upper bridles of low-rise cutback trawls significantly reduced Pacific halibut (Hippoglossus stenolepis) bycatch. Recent regulation changes in this fishery now permit high-rise trawls, a gear configuration with a higher vertical opening, in areas where only low-rise trawls were previously permitted. This study conducted catch comparison and catch ratio analyses to determine if catches of Pacific halibut and three commercially important groundfishes (e.g., petrale sole [Eopsetta jordani], Dover sole [Microstomus pacificus], and sablefish [Anoplopoma fimbria]) differ between illuminated and non-illuminated tows for a high-rise bottom trawl. Illuminated tows caught fewer individuals than the non-illuminated tows across all species, including Pacific halibut; however, the difference in catch efficiency was not significant. Total catch volume did have a significant positive effect on levels of glucose and lactate for Pacific halibut. However, no statistically significant differences between illuminated and non-illuminated tows were exhibited across all of the physiological parameters assessed. The results from our study provide valuable information to fishers and managers that can be used for future decision-making and identifying research priorities.