Floated fish pot eliminates bycatch of red king crab and maintains target catch of cod

Today bycatch of red king crab (Paralithodes camtschaticus) in stationary fishing gears targeting cod (Gadus morhua) is a severe problem in the Barents Sea, causing extra work for fishermen and damaging their gear and catches. Attempts to use bottom-set pots as an alternative to gillnets and longlines have been unsuccessful, as pots too are affected by large bycatches of crab. In this field study, pots were floated off the bottom in order to avoid crab bycatch. A standard two-chamber groundfish pot was modified by mounting a suspension arrangement that allowed the pot to orient itself with the current about 70 cm above the seabed. Fishing trials were conducted in the Varangerfjord (northern Norway) to compare floated and bottom-set reference pots. Floating the pots off the bottom eliminated king crab catches, while bottom-set pots caught an average of 21 crabs each. Moreover, floated pots caught significantly more cod than bottom-set pots (3.6 and 2.5 cod per pot, respectively), with the majority of the 45% increase being cod below minimum legal size. The catch increase was explained by the fact that the entrance of floated pots always maintained a down-current orientation, whereas in bottom-set pots shifting current directions may lead the odour plume away from the entrance, thereby reducing the rate of entry of cod. Full-scale fishing trials are needed in order to evaluate whether floated pots could become a commercially viable method of catching cod.