50 CFR § 648.20 - Mid-Atlantic Fishery Management Council Acceptable Biological Catch (ABC) control rules.

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§ 648.20 Mid-Atlantic Fishery Management Council Acceptable Biological Catch (ABC) control rules.

The SSC shall review the following criteria, and any additional relevant information, to assign managed stocks to one of four types of control rules based on the species' assessments and its treatment of uncertainty when developing ABC recommendations. The SSC shall review the ABC control rule assignment for stocks each time an ABC is recommended. ABCs may be recommended for up to three years for all stocks, with the exception of five years for spiny dogfish. The SCC may specify constant, multi-year ABCs, derived from the average of ABCs (or average risk of overfishing) if the average probability of overfishing remains between zero and 40 percent, and does not exceed a 50-percent probability in any given year. The average ABCs may remain constant for up to three years for all stocks, with the exception of five years for spiny dogfish. The SSC may deviate from the control rule methods and recommend an ABC that differs from the result of the ABC control rule application; however, any such deviation must include the following: A description of why the deviation is warranted; description of the methods used to derive the alternative ABC; and an explanation of how the deviation is consistent with National Standard 2. The four types of ABC control rules are described below.

(a)ABC control rule for a stock with an OFL probability distribution that is analytically-derived and accepted by the SSC.

(1) The SSC determines that the assessment OFL and the assessment's treatment of uncertainty are acceptable, based on the following:

(i) All important sources of scientific uncertainty are captured in the stock assessment model;

(ii) The probability distribution of the OFL is calculated within the stock assessment and adequately describes the OFL uncertainty;

(iii) The stock assessment model structure and treatment of the data prior to use in the model include relevant details of the biology of the stock, fisheries that exploit the stock, and data collection methods;

(iv) The stock assessment provides the following estimates: Fishing mortality rate (F) at MSY or an acceptable proxy maximum fishing mortality threshold (MFMT) to define OFL, biomass, biological reference points, stock status, OFL, and the respective uncertainties associated with each value; and

(v) No substantial retrospective patterns exist in the stock assessment estimates of fishing mortality, biomass, and recruitment.

(2) An ABC for stocks with an accepted OFL probability distribution that is analytically-derived will be determined by applying the acceptable probability of overfishing from the MAFMC's risk policy found in § 648.21(a) through (d) to the probability distribution of the OFL.

(b)ABC control rule for a stock with an OFL probability distribution that is modified by the assessment team and accepted by the SSC.

(1) The SSC determines the assessment OFL is acceptable and the SSC accepts the assessment team's modifications to the analytically-derived OFL probability distribution, based on the following:

(i) Key features of the stock biology, the fisheries that exploit it, and/or the data collection methods for stock information are missing from, or poorly estimated in, the stock assessment;

(ii) The stock assessment provides reference points (which may be proxies), stock status, and uncertainties associated with each; however, the uncertainty is not fully promulgated through the stock assessment model and/or some important sources of uncertainty may be lacking;

(iii) The stock assessment provides estimates of the precision of biomass, fishing mortality, and reference points;

(iv) The accuracy of the minimum fishing mortality threshold and projected future biomass is estimated in the stock assessment using ad hoc methods; and

(v) The modified OFL probability distribution provided by the assessment team acceptably addresses the uncertainty of the assessment.

(2) An ABC for stocks with an OFL probability distribution that is modified by the assessment team and accepted by the SSC will be determined by applying the acceptable probability of overfishing from the MAFMC's risk policy found in § 648.21(a) through (d) to the probability distribution of the OFL as modified by the assessment team.

(c)ABC control rule for a stock with an OFL probability distribution that is modified by the SSC.

(1) The SSC determines the assessment OFL is acceptable but the SSC derives the appropriate uncertainty for OFL based on meta-analysis and other considerations. This requires the SSC to determine that the stock assessment does not contain an estimated probability distribution of OFL or the OFL probability distribution in the stock assessment is judged by the SSC to not adequately reflect uncertainty in the OFL estimate.

(2) An ABC for stocks with an OFL probability distribution that is modified by the SSC will be determined by either:

(i) Applying the acceptable probability of overfishing from the MAFMC's risk policy found in § 648.21(a) through (d) to the SSC-adjusted OFL probability distribution. The SSC will use default assignments of uncertainty in the adjusted OFL probability distribution based on literature review and valuation of control rule performance; or,

(ii) If the SSC cannot develop an OFL probability distribution, a default control rule of 75 percent of the FMSY value will be applied to derive ABC.

(d)ABC control rule for when an OFL cannot be specified.

(1) The SSC determines that the OFL cannot be specified given the available information.

(2) An ABC for stocks with an OFL that cannot be specified will be determined by using control rules based on biomass and catch history and application of the MAFMC's risk policy found in § 648.21(a) through (d).

[83 FR 15512, Apr. 11, 2018]