"The Development and Testing of Deep-Set Buoy Gear for Swordfish in the Southern California Bight"

Fishery interactions with species of concern (i.e., turtles and marine mammals) have severely impacted U.S. west coast swordfish fisheries, resulting in historic lows in effort, landings, and revenue. Restrictions currently in place prohibit California’s primary swordfish industry from operating in the most productive waters off California and have constricted effort to the Southern California Bight, a relatively small portion of the historic fishery range.  Given the continued concern over bycatch in the CA swordfish fishery, the present study has focused on the use of swordfish depth distribution data to design a deep-set gear configuration to target swordfish within the California exclusive economic zone (EEZ).  To minimize interactions with species of concern, the deep-set gear was designed to fish below the thermocline (270 to 350m) during the daylight hours.  Gear specifications include the deployment of ten individual sets of deep-set gear which were comprised of two-8m gangions with 18/0 circle hooks.  All ten sets were soaked for four consecutive hours and baited with both mackerel and squid.  Gear trials were tested during the 2011 and 2012 swordfish seasons off the coast of southern California using both research and cooperative fisher vessels.  A total of 54 sets (4,320 hook-hours) were completed resulting in the capture of 15 swordfish without any interactions with species of concern.  Additional non-target catch included: bigeye thresher sharks, Alopias superciliosus (7), opah, Lampris guttatus (2), blue sharks, Prionace glauca (2) and common thresher shark, Alopias vulpinus (1).  These data suggest that deep-set buoy gear can selectively be used to target swordfish deep during the day off southern California.  Additional trials that investigate alternative configurations (i.e., gear modification, bait presentation) to further reduce bycatch interaction are currently underway.