Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 9066
Title: Illuminating the Headrope of a Selective Flatfish Trawl: Effect on Catches of Groundfishes Including Pacific Halibut
Author: Mark J.M. Lomeli, W. Waldo Wakefield, Bent Herrmann
Publication Year: In press
Journal: Marine and Coastal Fisheries

This study evaluated how illuminating the headrope of a selective flatfish trawl could affect catches of groundfishes, including Pacific Halibut, in the U.S. West Coast limited entry (LE) groundfish bottom trawl fishery. Over the continental shelf, fishermen engaged in the LE bottom trawl fishery target a variety of flatfishes, roundfishes, and skates. Green LED fishing lights (Lindgren-Pitman Electralume®) were used to illuminate the headrope. Lights were grouped into clusters of three, with each cluster attached ca. 1.3 m apart along the 40.3 m long headrope. Catch comparisons and ratios of mean fish length classes were compared between tows conducted with (treatment) and without (control) LED lights attached along the trawl headrope. Fewer Rex Sole, Arrowtooth Flounder, and Lingcod were caught in the treatment compared to the control trawl, however, not at a significant level. Pacific Halibut catches differed between the two trawls, with the treatment trawl catching an average of 57% less Pacific Halibut. However, this outcome was not significant due to a small sample size. For Dover Sole 31 cm to 44 cm in length and Sablefish 43 cm to 61 cm in length, significantly fewer fish of these lengths were caught in the treatment than the control trawl. Compared to the control, the treatment trawl on average caught more rockfishes, English Sole, and Petrale Sole, but not at a significant level. Findings show that illuminating the headrope of a selective flatfish trawl can affect the catch comparisons and ratios of groundfishes, and depending on fish length and species the effect can be positive or negative.

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