Review of the 2012 Pacific Bluefin Tuna Stock Assessment
The report of the Pacific bluefin tuna stock assessment conducted by International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean can be found here: ISC Stock Assessment of Pacific
Bluefin Tuna in 2012.
The
Pacific Bluefin Tuna Working Group (PBFWG) of the International Scientific
Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC)
conducts stock assessments of Pacific bluefin tuna to inform the ISC in its
deliberations on stock status and its development of science advice for the
multinational fisheries that exploit tuna and billfish stocks of the North
Pacific. PBFWG 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). NOAA Fisheries SWFSC scientists contributed to this assessment.
In
2012, the PBFWG completed an up-to-date assessment, building on previous
assessments of the stock. The objectives of the new assessment were to (1)
understand the dynamics of Pacific bluefin tuna by estimating population
parameters such as recruitment, biomass and fishing mortality; (2)
determine stock status by summarizing results relative to potential target and limit reference points (including MSY-based reference points); and (3) enable formulation of scientific advice for
fisheries managers on Pacific bluefin tuna conservation. The primary assessment
work was conducted during a a series of PBFWG workshops convened in 2011 and
2012 to prepare data sets, develop biological parameters and abundance time
series, investigate modeling approaches, and conduct the stock assessment. The
report summarizes the efforts directed towards completing the 2012 stock
assessment and reports results on the stock status and future outlook of
Pacific bluefin tuna. In March 2013, SWFSC solicited independent peer reviews
of the stock assessment report 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
ancillary documents and data, providing helpful background information.
Each
expert was asked to:
1.
Review the assessment methods to provide
recommendations on how to improve its application, and/or recommend other
methods that would also be appropriate for the species, fisheries, and
available data.
2.
Evaluate the assessment model configuration,
assumptions, and input parameters (fishery, life history, and spawner recruit
relationships) to provide recommendations on how to improve: the use of data,
specification of fixed input parameters, and specification of model
configuration.
3.
Provide recommendations on improving the
treatment of assumptions (e.g. sensitivity analyses) and description of
uncertainty in estimates of stock dynamics and management quantities (e.g.
reference points).
4.
Provide recommendations on improving the
adequacy, appropriateness, and application of the methods used to project
future population status.
5.
Suggest research priorities to improve the
stock assessment including data, life history and modeling.
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 the SWFSC with approval
for their distribution.
The
independent peer review reports are posted on this web page.
Peer Review report: Sylvain Bonhommeau
Peer Review report: Tom Carruthers
Peer Review report: Joseph E. Powers