A comparison of Pacific halibut and tanner crab catches in (1) side-entry and top-entry crab pots and (2) side-entry crab pots with and without tanner boards

Catch rates of Pacific halibut (Hippoglossus stenolepis) and Tanner crab (Chionoecetes bairdi) by several types of crab pot were compared. Top-entry crab pots had substantially lower catch rates of halibut than side-entry pots. Catch rates of legal Tanner crab in top-entry pots were only slightly lower than in side-entry pots, but the sample sizes were considered too small to clearly demonstrate this difference. "Tanner boards", which are placed horizontally across the upper half of the tunnel opening, reduced the catch rate of halibut by side-entry pots by 63%. In addition, the catch of halibut over 90 cm long was almost eliminated. Tanner boards also reduced the catch rate of Tanner crab by side-entry pots, but overall crab catches were not large enough to provide meaningful results. Further research is recommended on crab pot modifications, and an observer program is recommended to establish halibut incidence rates in the commercial crab fisheries.