March 11, 2003

Ms. Paticia Kurkul, Regional Administrator

National Marine Fisheries Service

One Blackburn Drive

Gloucester, MA 01930

Dear Pat:

 The Report on the Groundfish Science Peer Review Meeting (Report) was presented to the Council last week. It is unfortunate that the Report was not provided to the Council in mid-February as requested. This failure to meet an agreed-upon date resulted in a lengthy ad hoc discussion of the report and attempts by Council members to craft alternatives for Amendment 13 in response to the Report's recommendations. The Council is aware that you are not comfortable with these alternatives, which were developed without the time necessary to carefully consider the scientific, legal, and policy issues involved. In part because of this concern, we are tentatively planning an additional Council meeting in April to address these issues.

 Many Council members believe the Report supports the development of an alternative to the numerical estimates of biological reference points that were determined in the Reference Point Working Group Report in 2002. Some of the comments from the Report's summary that support this conclusion include:

      o       "An adaptive approach to using harvest management to control biomass is eminently sensible in the              light of uncertainty, and should be pursued." (p. 5)

o       "From a purely scientific perspective, the setting of an intermediate biomass target could be defended." (p. 5)

o       "Hence, calculation of MSY conditioned on such a relationship effectively forces extrapolation beyond the range of data, with consequent loss of credibility. Solving these problems requires a realistic interpretation of MSY in the light of incomplete data and knowledge." (p. 14)

o       "Moreover, a pragmatic solution to covering the substantial uncertainty in estimates of B_MSY, where for example they fall outside the observation range, could be to set them at a value closer to the range of actual observations. For example, a  B_MSY proxy could be set provisionally as the largest observed value in the historical time-series or some conventionally chosen percentage above the largest value. Then, once more years of data have been obtained, the proxy can be re-evaluated (this is a form of adaptive management advice, a protocol strongly supported below)." (p. 15)

o       "At a practical level, more is known about the region of undesirable stock size than about the region of desirable (and attainable) stock size for New England fish stocks. This presents both scientists and managers with considerable challenges if the law requires that stocks be rebuilt to a  B_MSY target within a specified time frame. The current state of knowledge means that it is easier to know the direction in which stock biomass should be driven than when or if  B_MSY can be attained, or even perhaps if such a target is overly conservative. Given this, the proposal by the working group to adopt an adaptive approach to biomass management seems eminently sensible. Provided target F values are achieved, biomass levels should evolve naturally to a state of  B_MSY through a process of rebuilding not dependent on theoretical levels of biomass." (p. 18)

o        “Due to the lack of a sound statistical-theoretical basis for the model selection procedure applied, the biological reference point results obtained for the groundfish stocks to which the protocol has been applied are in my view questionable. Simple modifications to the procedure for model selection are suggested above to provide a statistically consistent Bayesian methodology appropriate to the Bayesian MCMC estimation procedure already adopted by the NEFSC for reference point estimation (Anon. 2002).” (p. 30)

o       “For the Gulf of Maine cod, this potential misrepresentation in the patterns of the data could misrepresent the ability of the estimation procedures applied to detect the correct stock-recruit function. It is thus advised that the simulation testing procedure be redone to adequately represent the key features in the actual observed stock-recruit data such as the nearness of points to the origin on the spawner axis.” (p. 31)

 Based on the recommendations of the Peer Review, we ask that the National Marine Fisheries Service provide the Council with scientifically defensible intermediate biomass targets (that is,  B_MSY targets lower than those recommended by the Reference Point Working Group) that can be used in the development of Amendment 13. These  B_MSY targets should be provided in time for a Council meeting in April so that they can be incorporated into the Amendment. We believe this may be the only approach to adaptive management that is consistent with current law.

Another issue of concern to the Council is the many technical recommendations included in the Report. Some of these are obviously long-range research recommendations. Others, however, bear directly on the reference points developed by the Reference Point Working Group. For example, some recommendations that appear to be important to investigate immediately include

o       The Report notes that the use of either Beverton-Holt or Ricker spawner-recruit relationship assumes that the biological attributes are well-estimated and stationary and notes neither issue was investigated in detail. When will these issues be explored? (p. 15)

o       The Report questions the model selection criteria used by the Working Group. Specifically, the Report says that AIC should not be used as a model selection criteria for the Bayesian statistical model used, and the AIC value was incorrectly applied. (p. 16)

o       The Report questions whether models with autocorrelation should be tested statistically against models without such correlation, given the limited time series of data, and suggests other objective criteria need to be developed for determining when to include autocorrelation in models used to estimate F_MSY  and B_MSY. (p. 17)

o       The Report suggests that application of an Age Structure Production Model, if configured similarly to the models used by the Reference Point Working Group, would be expected to yield similar results. The Report notes that differences in values may be caused by an insufficiency of the observed information to estimate parameters of the population model. This would be useful information to evaluate the proposed reference points. (p. 17)

Please have the NEFSC identify which technical recommendations could affect the numerical estimates of reference points developed by the Working Group, and advise when these specific recommendations can be incorporated into the analyses. In addition, please advise when we can expect to see a comparison between reference points developed through an Age Structured Production Model and the Working Group reference points, accompanied with an explanation of the differences between the two.

 The Groundfish Science Peer Review Meeting was conducted with extensive support and participation from the NEFSC, Council, and industry stakeholders. In addition, Sec. 303 (a) (3) of the Act states, “Councils shall assess and specify the present and probable future condition of, and the maximum sustainable yield and optimum yield from, the fishery, and include a summary of the information utilized in making such specification.”  The National Standard Guidelines state, “because MSY is a theoretical concept, its estimation in practice is conditional on the choice of an MSY control rule.  In choosing an MSY control rule, Councils should be guided by the characteristics of the fishery, the FMP's objectives, and the best scientific information available.”  Furthermore, the Guidelines state that “any MSY values used in determining OY will necessarily be estimates, and these will typically be associated with some level of uncertainty.  Such estimates must be based on the best scientific information available and must incorporate appropriate consideration of risk.  Beyond these requirements, however, Councils have a reasonable degree of latitude in determining which estimates to use and how these estimates are to be expressed.”

 This language, in context of the peer review reports, would seem to provide the Council with considerable latitude to select intermediate reference points.  Even the statement above (“...must be based on the best scientific information available...”) is qualified in the very same sentence by the statement that such evaluations “...must incorporate appropriate consideration of risk.”  The panelists said the risk is in setting the B_MSY values too high.  Our response to that advice should be to set the B_MSY values somewhat lower and see how things go as we approach the higher values.

 We must take to heart the recommendations of this peer review, along with the Act and the National Standard Guidelines. It is crucial that we move forward and incorporate the Report's recommendations into Amendment 13. We look forward to working with you to do so.

                         Sincerely,

                        Thomas R. Hill

                        Chairman

cc:     Dr. William Hogarth, NOAA/NMFS

Dr. John Boreman, NEFSC