CIE Peer Review

Subject Time-Area Closures In the Hawaii-Based Longline Swordfish Fishery
Document(s) Reviewed
Li S, Pan M
Fishing Opportunities under the Sea Turtle Interaction Caps – A Spatial Bio-economic Model for the Hawaii-based Longline Swordfish Fishery. Unpublished draft document for review only. NOAA Pacific Islands Fisheries Science Center, June 2010, 56 pp.
Download (0.4 MB PDF)
Date June 2010

A significant management issue in the Hawaii longline fishery for tuna and swordfish is the incidental capture of sea turtles protected under the U.S. Endangered Species Act. The turtle bycatch problem is particularly challenging in the segment of the fishing fleet that targets swordfish in oceanic waters north of the Hawaiian Islands. Fishers must abide by strict fleet-wide annual upper limits on incidental turtle captures. The NOAA Fisheries Service monitors the turtle bycatch on each fishing trip; if the cumulative fleet bycatch exceeds the annual allowance, the fishery will be closed for the remainder of the year, leading to economic losses. Studies have shown that during the primary season for swordfish fishing, turtles favor pelagic habitat where swordfish are also likely to be relatively abundant. Consequently, fishers pursuing swordfish in these areas must weigh their expectation of higher swordfish catches, and economic gain, against the higher risk of encountering turtles and approaching the critical threshold for turtle bycatch. Research on the problem has focused around finding time-area regulatory strategies that will enable fishers to achieve maximum net economic returns subject to the constraint on turtle encounters.

Li and Pan, in the research reviewed, significantly expanded the scope of Hawaii longline fishery time-area modeling and analysis published earlier by PIFSC scientists Don Kobayashi and Jeff Polovina. In particular, they incorporated new information on reduced turtle bycatch rates (due to new regulations requiring circle hooks and mackerel bait), survey data on costs of fishing as a function of location and time, and ex-vessel prices of swordfish and other fish species caught. The additional economic information provided a richer framework for simulating fisher decisions on where and when to fish, and designing time-area closures, trading off risks of encountering sea turtles against risks of economic loss.

To provide a thorough, objective assessment of this research, PIFSC solicited a peer review of the Li-Pan study through the Center for Independent Experts (CIE). The CIE established a panel of two peer reviewers and contracted them to review the Li-Pan document and convene at the Pacific Islands Fisheries Science Center, Honolulu, Hawaii during 28-30 June 2010 for a 3-day meeting with Minling Pan and other PIFSC staff. Pan made presentations to the review panel and provided in-depth responses to reviewer questions. The reviewers were asked by the CIE to prepare independent reports of their findings and recommendations to improve the research.

The reviewer reports are provided here in PDF format.

Under Minling Pan's direction, the time-area research will continue, taking into account suggestions of the reviewers to develop a comprehensive research plan, adopt a more robust, stochastic framework for modeling and estimation, build sub-models that describe fisher behavior in response to time-area closures, and more.

— Samuel G. Pooley, Director

Reviewer Comments

Dr. Rangar Arnason
Professor, Department of Economics
University of Iceland
Reykjavik, Iceland
Comments (0.5 MB PDF)

Dr. Jon Conrad
Charles H. Dyson School of Applied Economics and Management
Cornell University
Ithaca, New York 14853
Comments (0.5 MB PDF)