PIFSC Sea Turtle Longline Research EA June 1, 2009
loggerhead sea turtle bycatch with circle hooks, especially larger hook sizes (16/0 and 18/0) (44% to 88% reduced interaction rates; 63% to 93% reduced mortality). Tuna catch rates were not affected, but catch rates of smaller hooks used in the mahimahi fishery (14/0 and 15/0) were reduced. Interaction rates in that fishery were reduced 16% to 37% (41% to 93% reduced mortality). More than 15,000 circle hooks were exchanged for J hooks on 115 participating vessels, and observers were placed aboard the vessels to document protected species interactions and catch rates of target species (Largacha et al. 2005).
PIFSC continued collaborative research efforts with foreign fleets and countries: The intention of this continued collaboration is to assist foreign fleets having frequent interactions with sea turtles to work toward conservation of sea turtles and to collect pertinent data about longline-sea turtle interactions. Many foreign fisheries have sea turtle catch rates are believed to be higher than in the highly regulated U.S. fisheries (Section 1.2.3, Table 1).
This work provides an opportunity to collect statistically powerful results regarding the efficacy of alternate gear in reducing turtle bycatch. At the same time, the opportunity to convert even a portion of the gear used in these fisheries to more turtle-friendly alternatives in experimental trials has some immediate benefit in reducing global fisheries’ bycatch. The experiments are conducted in fisheries that would otherwise have continued to operate with traditional gear, and thus would not increase incidental takes of sea turtles. The effort involves providing funds to hire observers, circle hooks to use and test, and technical advice and support for modifying operations. Advice and support for turtle bycatch reduction efforts include a variety of activities that do not often involve financial assistance, but require the time of NOAA Fisheries personnel and collaborating researchers funded through grants, including suggesting designs for experiments, and providing guidelines and training in sea turtle handling and release, forms and instructions for the collection of data, advice and assistance in the statistical analysis of data, and help in interpreting results and deriving recommendations for the types of management measures that could be effective in reducing sea turtle bycatch in different fisheries. Currently, work has been conducted in foreign fleets from Japan, Brazil, Ecuador, Peru, Guatemala, Ecuador, Chile, El Salvador, Uruguay, Spain, Italy, Indonesia, Papua New Guinea, Vietnam, and the Philippines, and is currently working with Brazil to initiate a program.
Long-term research on sea turtle bycatch by PIFSC: The Honolulu Laboratory (now PIFSC) began monofilament longline research in 1989 after a decades-long hiatus in longline research. Since 1989, 30 longline research cruises have been conducted for a total of 686 sea-days. The NOAA vessel longline research is conducted for many purposes, but primarily to investigate the selectivity of longline gear for target species while reducing bycatch of nontarget species and to study fish catchability in relation to depth and other oceanographic variables. Research is also conducted on pelagic fish and sea turtle behavior and physiology to better understand gear selectivity and catchability. Future research would include testing gear modifications to reduce selectivity for epipelagic fish bycatch, which might have spin-off benefits for sea turtles.
PIFSC laboratory studies of sea turtle sensory and behavioral biology, effects of repellents, and deployment of satellite archival tags on free-swimming turtles: In 2007, PIFSC prepared an EA (Sea Turtle Bycatch Reduction Research Activities, PIFSC, Finding of No Significant Impact signed June 7, 2007) that focused on testing gear and researching various methods that have