CIE Peer Review

Deepslope bottomfish support important fisheries in Hawaii, providing significant benefits to both commercial and non-commercial fishers and consumers. Fishery management strategy for Hawaii bottomfish developed by the Western Pacific Regional Fishery Management Council is focused on a group of 7 high-value species (six snappers and a grouper) known as the "Deep 7". In 2010, scientists at PIFSC conducted a stock assessment of the Deep7 complex using data through fishing year 2010 (viz., July 1, 2009 through June 30, 2010), including projections to determine total allowable commercial catches (TACs) and their probabilities of overfishing. The assessment was based on catch and effort data from commercial catch reports for the years 1948-2010, re-audited to correct flaws in previous data compilations. A standardized bottomfish catch-per-unit effort (CPUE) data set was constructed for the main Hawaiian Islands using re-audited catch and effort data. Model selection techniques were applied to choose the structural form on which CPUE standardization was based.

The 2010 stock assessment took into account recommendations of experts who reviewed a previous stock assessment of Hawaii bottomfish, conducted in 2008. Those recommendations were made by the Western Pacific Stock Assessment Review panel and an independent reviewer provided by the Center for Independent Experts (CIE) in June 2009. The 2010 stock assessment directly addressed the following issues raised by the panel and CIE reviewer: (i) develop credible standardized CPUE time series; (ii) construct noncommercial bottomfish catch histories; (iii) develop an informative prior for intrinsic growth rate using metadata or other analyses; and, (iv) assess the main Hawaiian Islands bottomfish complex as a single stock unit and ensure appropriate testing of CPUE uncertainty through sensitivity analyses. A Bayesian production model was used to estimate time series of Deep7 bottomfish exploitable biomasses and harvest rates under alternative scenarios of unreported catch and standardized CPUE. The production model was also used to compute stochastic short-term projections of future catches and associated risks of overfishing. These projections explicitly included uncertainty in the posterior distribution of estimated bottomfish biomass in 2010 and population dynamics parameters. The 2010 stock assessment report describes results of the catch and CPUE analyses, production modeling, and projections. It also provides tables to address uncertainty about the effects of selecting commercial fishery Deep7 TACs for fishing years 2012-2013 under alternative CPUE scenarios.

In late January, 2011, the 2010 stock assessment was critically reviewed by three independent experts provided by the CIE through a solicitation by PIFSC. Reviewers were provided with the draft stock assessment document and several background documents detailing ancillary analyses and previous stock assessments. Each reviewer was charged with preparing a report providing their independent findings and recommendations to the CIE and specifying whether the 2010 stock assessment reviewed is the best scientific information available. Reviewers were asked to work under the following terms of reference:

1. Determine if recommendations from the 2009 WPSAR/CIE review have been adequately addressed within the assessment update.
2. Review the assessment methods used: determine if they are reliable, properly applied, and adequate and appropriate for the species, fisheries, and available data.
3. Evaluate the implementation of the assessment model: configuration, assumptions, and input data and parameters (fishery life history); more specifically determine if data are properly used, if choice of input parameters seem reasonable, if models are appropriately specified and configured, assumptions are reasonably satisfied and primary sources of uncertainty accounted for.
4. Comment on the scientific soundness of the estimated population benchmarks and management parameters (e.g. MSY, Fmsy, Bmsy, MSST, and MFMT) and their potential efficacy in addressing the management goals stated in the relevant FMP or other documents provided to the review panel.
5. Evaluate the adequacy, appropriateness, and application of the methods used to project future population status.
6. Evaluate the adequacy, appropriateness, and application of the methods used to project future population status.

The final reports of the CIE peer reviewers were forwarded by the CIE to PIFSC in February 2011. Subsequently, PIFSC scientists addressed suggestions and comments of the CIE reviewers, and other experts, and revised the stock assessment document accordingly. The final edited version of the stock assessment document is being made available in PDF format through the link at the top of this page. The reports of the independent CIE reviewers are also available through the links below.

— Samuel G. Pooley, Director