CIE Peer Review

Subject North Pacific Swordfish Stock Assessment
Document(s) Reviewed
Brodziak J, Ishimura G
2010. Stock assessment of North Pacific swordfish (Xiphias gladius) in 2009. NOAA Pacific Islands Fisheries Science Center, Administrative Report H-10-01, 37 p.
Download (0.7 MB PDF)
Date April 2010

Swordfish are harvested in the North Pacific by fleets of Japan, Korea, Taiwan, and the United States. The fishing effort and catch - about 18,400 metric tons of swordfish were caught in 2008 - are monitored by the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC). Stock assessments of North Pacific swordfish are conducted by the ISC's Billfish Working Group (BILLWG). Based on the assessments, the ISC provides scientific advice on the swordfish stocks and fisheries harvesting them to ISC member governments and regional fishery management organizations.

At its meeting in May 2009, in Busan, Korea, the BILLWG conducted a new stock assessment of swordfish in the North Pacific using Bayesian surplus production models. The stock assessment followed an assessment plan developed by the BILLWG, including guidance on model structure, biological parameters, input data, and other matters. The assessment was documented in a draft report by working group members Jon Brodziak of the NOAA Pacific Islands Fisheries Science Center (PIFSC, U.S.A) and Gakushi Ishimura of the Center for Sustainability Science, Hokkaido University (Japan). Results of the swordfish stock assessment were presented by Brodziak to the ISC Plenary in Kaohsiung, Taiwan, in July 2009.

In December 2009, PIFSC solicited independent peer reviews of the Brodziak and Ishimura 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 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.

Although the review pertained to the listed 2009 stock assessment report, the reviewers also had access to related documents prepared by scientists of the BILLWG; reviewers were free to consult these ancillary documents, and published literature, as they deemed appropriate.

The reviews were completed, submitted to the CIE, and forwarded by the CIE to PIFSC in February 2010. The reviewed document was published unmodified, except for minor editorial corrections, as a PIFSC Administrative Report, which is posted above. The independent reports of the CIE reviewers are provided below.

Using an expanded set of input data, the BILLWG is undertaking a new stock assessment of North Pacific swordfish. In the process, the working group is taking into consideration the comments and recommendations of the CIE reviewers.

— Samuel G. Pooley, Director

Reviewer Comments

Dr. Panayiota Apostolaki
Center for Environment, Fisheries & Aquaculture Science
Lowestoft, UK
Comments (0.3 MB PDF)

Dr. Noel Cadigan
Fisheries and Oceans Canada, Northwest Atlantic Fisheries Center
St. John's, NL, Canada
Comments (0.3 MB PDF)

Dr. Graham Pilling
Center for Environment, Fisheries & Aquaculture Science
Lowestoft, UK
Comments (0.3 MB PDF)