Highlighted Gear

Hawai’i based longline swordfish fishery

The Hawai’i based swordfish longline fishery was closed completely in 2000 due to concern about high frequency of interactions with loggerhead and leatherback sea turtles.  Additionally, seabirds were also being taken as bycatch in this fishery.  The fishery was reopened in 2004 under strict management regulations.  First, a cap was put in place for maximum numbers of interactions with leatherbacks (16) and loggerheads (17). Second, various mitigation measures were introduced to reduce bycatch of sea turtles (wide-set circle hooks with fish bait instead of narrow-set J hooks with squid bait) and seabirds (night setting with blue-dyed bait).  Third, annual effort was restricted and 100% observer coverage was mandated for this fishery.  In 2004 and 2005, the fishery did not approach the interaction limit for either species. In addition, these mitigation measures significantly reduced sea turtle bycatch rates and the frequency of serious injury to turtles (Gilman et al. 2006). Although there had been concern over how the new mitigation measures would affect catch rates, swordfish catch was similar to pre-closing levels (Gilman et al. 2006).  Despite the success of these mitigation measures in reducing bycatch rates in 2004 and 2005, the Hawai’i longline fishery was closed in March 2006 for the remainder of the year after reaching the limit of 17 interactions with loggerhead turtles since 1 January 2006.  The underlying reason for the high level of bycatch in the 1^st quarter of 2006 is unknown, but it does reflect the general trend of higher sea turtle bycatch early in the year.  One possible explanation concerns changes in oceanographic conditions that concentrated fishing effort and turtle habitat in time and space (NMFS 2006).

Reference:

Gilman, E., D. Kobayashi, T. Swenarton, P. Dalzell, I. Kinan, N. Brothers. 2006. Analyses of Observer Program Data for the Hawaii-Based Longline Swordfish Fishery for (i) Effects of Sea Turtle Regulations on Sea Turtle Interactions, Catch Rates of Retained Marketable Species and Catch Rate of Sharks; (ii) Economic Viability and Potential for Temporal or Spatial Closures to Reduce Turtle Captures; (iii) Comparison Between 2005 and 2006 Turtle Catch Rates and Temporal Distribution of Effort to Explain the Cause of a Loggerhead Cap Being Reached in 2006 and not 2005; and (iv) Hook Position of Caught Turtles and Fish. Western Pacific Regional Fishery Management Council, Honolulu, HI, USA.