CIE Peer Review

The Billfish Working Group (BILLWG) of the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC) conducts stock assessments of billfish resources to inform the ISC in its deliberations on stock status and its development of conservation and management advice for the multinational fisheries that exploit tuna and billfish stocks of the North Pacific. BILLWG stock assessments are based on the best fishery statistics and biological data available and are conducted cooperatively by scientists from ISC members China, Japan, Korea, Mexico, Taiwan, and the USA and collaborating scientists from the Inter-American Tropical Tuna Commission and the Secretariat of the Pacific Community (SPC).

Recently, the BILLWG completed an up-to-date assessment of striped marlin in the Western and Central Pacific Ocean, building on previous assessments of the stock, revised compilations of fishery data, and considerable new biological research, including studies of striped marlin genetics. The objectives of the new assessment were to (1) understand the dynamics of Western and Central Pacific Ocean striped marlin by estimating population parameters such as time-varying recruitment, biomass and fishing mortality; (2) determine stock status by summarizing results relative to MSY-based limit reference points; and (3) enable formulation of scientific advice for fisheries managers on striped marlin conservation needs by constructing a decision table based on stock projections using both constant-catch and constant-fishing mortality scenarios. The primary assessment work was conducted during a BILLWG workshop at the East-West Center on the University of Hawaii campus in Honolulu, Hawaii, held 6-16 December 2011, with follow-up stock projections developed during a 2-9 April 2012 workshop at Shanghai Ocean University, Shanghai, China. A report of the stock assessment, including methodology, assumptions and results, was prepared by USA members of the BILLWG and presented to the 12^th Plenary Session of the ISC in Sapporo Japan, in July 2012. In October 2012, PIFSC solicited independent peer reviews of the stock assessment report [specified above as "document reviewed"] through the Center for Independent Experts (CIE), assisted by the NMFS Office of Science and Technology (F/ST). The CIE engaged 3 experts to independently conduct a thorough review of the stock assessment report. In addition to the stock assessment report, each reviewer was provided with several ancillary documents, including published scientific articles, providing helpful background information.

Each expert was asked to:

1. Review of the assessment methods: determine if they are reliable, properly applied, and adequate and appropriate for the species, fisheries, and available data.
2. Evaluate the assessment model configuration, assumptions, and input data and parameters (fishery, life history, and spawner-recruit relationships): determine if data are properly used, input parameters seem reasonable, models are appropriately configured, assumptions are reasonably satisfied, and primary sources of uncertainty accounted for.
3. Comment on the proposed population benchmarks and management parameters (e.g., MSY, F_MSY, B_MSY, MSST, MFMT); if necessary, recommended values for alternative management benchmarks (or appropriate proxies) and clear statements of stock status.
4. Evaluate the adequacy, appropriateness, and application of the methods used to project future population status.
5. Suggest research priorities to improve our understanding of essential population and fishery dynamics necessary to formulate best management practices.

Each reviewer prepared a peer-review report of findings and recommendations, addressing in particular the points listed above and delivered the report to the CIE. After the CIE and F/ST verified that the peer-review reports satisfied the terms of reference, F/ST provided the reports to PIFSC in late December 2012 with approval for their distribution.

The independent peer review reports are posted on this web page.

The authors are undertaking further analysis to clarify and expand on the striped marlin stock assessment. This analysis will take into consideration the many useful and constructive comments and suggestions of the CIE peer reviewers. Upon completion of this work a revised striped marlin stock assessment document will be released.

— Samuel G. Pooley, Director