CIE Peer Review

Subject Pacific Blue Marlin Stock Assessment
Document Reviewed
2013. Stock assessment of blue marlin in the Pacific Ocean in 2013, report of the Billfish Working Group, 13th Meeting of the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean, Busan, Korea, 17-22 July 2013. 118 pp.
Download (5.3 MB PDF)
Date 03 March 2014

Blue marlin occurs in tropical and sub-tropical waters of the Atlantic, Pacific and Indian Oceans. In the Pacific, the species is prized by recreational fishermen and is also caught and marketed in commercial fisheries, primarily as bycatch of longline fleets targeting tropical tunas. Current genetic evidence supports the assumption of a single blue marlin stock in the Pacific. Assessments of the stock have been carried out periodically using fishery-dependent data compiled and shared by the harvesting nations through international working groups.

In 2013, a new Pacific blue marlin assessment was conducted by the Billfish Working Group (BILLWG) of the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC). Using best available biological information and fishery statistics provided by ISC member countries, the BILLWG applied a size-based, age-structured, sex-specific stock assessment model known as Stock Synthesis. The work was accomplished by BILLWG scientists of ISC members Japan, Chinese Taipei (Taiwan), and the United States, and the Inter-American Tropical Tuna Commission (IATTC, a cooperating ISC non-member) during a workshop convened 20-28 May 2013 in Shimizu, Japan; that session was preceded by a preparatory workshop held 16-23 January 2013 in Honolulu, Hawaii. The stock assessment report prepared by the BILLWG was presented to the ISC during its July 2013 plenary meeting in Busan, Republic of Korea. Assessment results inform the ISC in its development of scientific advice on conservation and stock status of pelagic fish stocks in the North Pacific Ocean. ISC findings are published on the ISC website and made available to regional fisheries management organizations, including the Western and Central Pacific Fisheries Commission (WCPFC) and the IATTC.

In November 2013, PIFSC solicited independent peer reviews of the blue marlin stock assessment report through the Center of Independent Experts (CIE).

The CIE selected three expert scientists and asked each one to conduct an independent "desktop review" of the draft report, abiding by the following terms of reference:

  1. Review 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 are accounted for.
  3. Comment on the proposed population benchmarks and management parameters (e.g., MSY, FMSY, BMSY, MSST, MFMT); if necessary, recommend 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.

Along with the 2013 stock assessment report, the reviewers were provided several ancillary documents pertinent to the review; these were primarily BILLWG working papers on blue marlin biology, catch statistics, CPUE standardization, an alternative stock assessment, and other topics. Reviewers were free to consult these supplementary documents as they deemed appropriate.

In March 2014, each reviewer completed and submitted to the CIE an independent review report. These reports are provided below.

Comments and recommendations of the CIE reviewers are being carefully vetted by members of the BILLWG and will be taken into consideration by the working group as the ISC seeks to improve its assessment of the Pacific blue marlin stock.

— Samuel G. Pooley, Director

Reviewer Comments

Daniel Gaertner
Institut de Recherche pour le Développement (IRD) UR 109
Centre de Recherche Halieutique Méditerranéenne et Tropicale (CRHMT) BP 171
34203 Séte Cedex, France
Comments (0.4 MB PDF)

Jean-Jacques Maguire
1450 Godefroy
Québec, Qc, Canada
G1T 2E4
Comments (0.2 MB PDF)

John D. Neilson, Ph.D.
10 Moss Drive
Chamcook, New Brunswick, Canada
E5B 3G7
Comments (0.7 MB PDF)

Author Response No response