Spatial Modeling of the Tradeoff between Sea Turtle Take Reduction and Economic Returns to the Hawaii Longline Fishery

(Note: As of January 2005, Dr. Minling Pan of the NMFS-PIFSC has taken over as lead PI for this project)

Progress Reports: FY 2008, FY 2007, FY 2006, FY 2005

Project Overview
This proposal describes research to advance ecosystem-based fishery management by updating previously published economic models for the Hawaii-based longline fishery (HILLF) and by using the updated models to estimate economic returns associated with either current or proposed time/area closure policies. As such, this proposed work should be useful to assess the benefits (i.e., reducing incidental takes of sea turtles) and costs (i.e., fishers' income loss) of management policies.

The objective of this project is to incorporate a time/area closure model (K-P model) previously developed to estimate sea turtle takes (Kobayshi-Polovina, 2001a, 2001b) into a multilevel and multiobjective programming model developed in an ongoing PFRP project (MMPM2). This updated model will then be used to estimate economic returns and incidental takes of sea turtles over space and time under existing and potential regulatory policies. Ideally, this model should enable regulators and fishers to develop policies that would direct fishing effort to areas and times that will maximize economic return and minimize protected species interactions.

The specific objectives are to:

1. Develop an integrated ecosystem database, combining with fishery technical data (logbook and observer's data), market data, and cost-earnings/socioeconomic data;
2. Improve the fishing vessel's behavior model of the MMPM2; and
3. Incorporate the K-P model's method or more updated one to estimate incidental turtle takes and kills into the MMPM2.

Proposed Activities include:

1. Development of data processors to generate updated parameters from various databases, including the longline logbook data, the data collected by the Hawaii Longline Observer Program, and auction data from United Fishing Agency (UFA) and the State of Hawaii Division of Aquatic Resources (HDAR). The data processor developed under the MMPM2 project can be reused for this project.
2. Enhancing the current economic model (MMPM2) by incorporating various fishers' behavioral assumptions: No-Displacement, Displacement, Open Access, and Discrete Fleet Dynamic Model.
   Because of the contributions by the K-P model and other latest findings regarding turtle takes, the ranges for the area and months of time/area closure considered to reduce turtle takes are much narrower. Therefore, a "spatial/temporal" sensitivity analysis will be conducted. The data processors developed in MMPM2 will be used for this sensitivity analysis.
3. Entail estimation of sea turtles incidental takes and their percent reduction. Data collected by the Hawaii Longline Observer Program will be used for this estimation.
   The K-P model integrated the estimates of turtle takes and kills during 1994-1999 provided by McCracken (2000) using generalized additive models (GAM). That is, the predicted takes of each sea turtle species for each area and month based on the historical average level of effort will be obtained and then adjusted to reflect changes in effort caused by closure, other regulations, or season. The proposed work will follow the same method as the K-P model in the first phase. The data collected by the Hawaii Longline Observer Program of the NMFS will be used for this estimation. As the project progresses, researchers will improve the forecasts of turtle takes by incorporating recent findings and/or other data sets.
4. To develop decision support guidelines for policy making.
   MMPM2 already has a mechanism to easily generate a "tradeoff frontier " where net return is maximized given the expected turtles takes and kills (Pan et al. 2001). However, no guidelines/formal procedures to make a final choice are currently available, although many informal discussions are ongoing. The political atmosphere (including court litigations) is in flux and dynamic, while new scientific results are coming available. Compared with the situation on March 2001 when the current regulation was imposed, economic hardship of the Hawaii longliners is well recognized, while the effectiveness of the current regulations for saving sea turtles become more questionable because the regulation on the HILLF transfer the opportunity of catching swordfish to non-Hawaii vessels, which would have much higher probability for interact sea turtles (Kaneko and Bartram "Measuring the environmental baggage in global marketing of pelagic longline fishery products" at PFRP PI meeting, Dec. 2003). Furthermore, the current sea turtle conservation policy (i.e., prohibiting shallow sets) results in a significant increase in catch of bigeye tuna, while Hampton et al. (2003) warns that bigeye tuna stock in the Central North Pacific might be over-fished. The proposed work will provide some methodological guidelines and recommendations to mitigate such issues.

Year 1 funding for this 2-year project to be awarded in mid 2004.

Literature cited:
• Kobayashi, D. and J. Polovina. 2001a. Time/area closure analysis for turtle take reductions, in NMFS (Ed.). Final Environmental Impact Statements (FEIS), Vol. 2, Appendix C.

• Kobayashi, D. and J. Polovina. 2001b. Evaluation of mitigation measures for sea turtle take reduction in the Hawaii-based longline fishery. Oceans 3: 1595.

• McCracken, M.L. 2000. Estimation of Sea Turtle Take and Mortality in the Hawaii Longline Fisheries. Honolulu Laboratory, Southwest Fisheries Service Center, National Marine Fisheries Service, NOAA, Administrative Report H-00-06.

• Pan, M., P.S. Leung, F. Ji, S.T. Nakamoto, and S.G. Pooley. 2001. A decision support model for fishery management in Hawaii: a multilevel and multiobjective programming approach. North American Journal of Fisheries Management 21:293-309.

Dr. Keiichi Nemoto
National Marine Fisheries Service
PIFSC
Honolulu Laboratory
2570 Dole Street
Honolulu, Hawaii 96822 USA
Phone (808) 983-5323
FAX (808) 983-2902
email: Keiichi.Nemoto@noaa.gov