PIFSC Sea Turtle Longline Research EA June 1, 2009
1Table adapted from Beverly and Chapman (2007). Only information that is relatively complete is included.
Figure 2. Sea turtle bycatch to target catch ratios (per 190,000 kg of fish) of the Hawaii- based longline fisheries for swordfish (shallow-set) and tuna (deep-set) with other longline fisheries operation in the central and western Pacific (Kaneko and Bartram 2008).
The shallow-set component of the Hawaii-based longline fishery traditionally interacted with far more turtles than the deep-set component, although mortality of turtles in shallow-set gear is typically lower than in deep-set gear because turtles are more likely to be able to reach the surface to breathe in shallow sets (NMFS 2008a). The Hawaii-based shallow-set longline fishery fleet experienced almost 90% reduction in sea turtle bycatch from the period before turtle regulations were implemented and after such implementation (Gilman and Kobayashi 2007, Gilman et al. 2007, Kaneko and Bertram 2008, Figure 3). After the regulations were implemented, the 2007 shallow-set component of the Hawaii-based longline fishery had 5 interactions with a leatherback turtle, 15 with a loggerhead turtle, and 1 with an olive ridley turtle, down from an estimated annual bycatch of 7 green turtles, 34 leatherback turtles, 21 loggerhead turtles, and 42 olive ridley turtles before the regulations were instituted (NOAA Southwest Region Report 2008).