Testing of an industry-designed bycatch reduction device to reduce the incidental catch of Pacific halibut in a groundfish bottom trawl fishery

A flexible sorting grid designed by industry was tested in the US west coast groundfish trawl fishery for its ability to reduce bycatch. The flexible sorting grid was made within a four-seam tube of netting, 50 meshes deep and 88 meshes in circumference. The grid was inserted between the intermediate section of the bottom trawl and the codend. A horizontal sorting panel crowds fish and directs them through an escape opening in the bottom of the trawl. A recapture net was used to quantify retention and escapement. Bycatch of Pacific halibut was reduced by 83.7% and 74.3% by weight and numbers, respectively. Pacific halibut larger than 80 cm had the highest escapement rates. Retention rates for target species were 93.3 % (arrowtooth flounder), 99% (Dover sole) amd 96.9% (petrale sole). Sablefish retention was 90% and shortspin thronyhead retention was 96.9%. Sablefish over 79 cm in size represented 50% of the total loss of target species.