Tests of Artificial Light As a Bycatch Reduction Technology in the Ocean Shrimp (Pandalus jordani) Trawl Fishery)

We investigated how artificial light near the rigid-grate bycatch reduction device (BRD) and along the fishing line of an ocean shrimp (Pandalus jordani) trawl altered fish bycatch and shrimp catch.  We used double-rigged shrimp nets, one incorporating lights and the other as a control. We tested 1-4 Lindgren-Pitman Electralume^® LED lights near the BRD, and 10 green lights along the trawl fishing line. Both experiments were conducted with rigid-grate BRDs installed in each net.  In 12 hauls, lights near the BRD increased eulachon (Thaleichthys pacificus) bycatch by 104% (P=0.0005) and slender sole bycatch (Lyopsetta exilis) by 77% (P=0.0082), with no effect on shrimp catch (P>0.05).  In 42 hauls, the addition of lights on the fishing line reduced the fish bycatch greatly with no effect on shrimp catch (P>0.05).  Eulachon bycatch was reduced 91% (P=0.0001).  Bycatch of slender sole and other flatfishes were each reduced by 69% (P<0.0005).  Bycatch of darkblotched rockfish (Sebastes crameri) was reduced by 82% (P=0.0001) while the bycatch of other juvenile rockfish (Sebastesspp) was reduced by 56% (P=0.0001). In both experiments the addition of light appears to have increased the passage of fishes through restricted spaces that they typically would avoid under ambient seafloor light conditions.