The 2007 amendments to the Magnuson-Stevens Fishery Conservation and Management Act required fishery management plans (FMP) to establish mechanisms for specifying annual catch limits at such levels that overfishing does not occur.
Additionally, the Act calls for measures to ensure accountability with these limits, and that the limits do not exceed the scientific recommendations made by the regional fishery management councils’ scientific committees. Staff contact is Diana Stram: 907-271-2806.
FMPs and Modifications to Meet ACL Requirements
BSAI & GOA Groundfish FMPs
Amendment 96 (BSAI) and 87 (GOA)
Primary changes to meet revised MSA requirements were to redefine categories of species under the FMP:
- Target species were identified as ‘in the fishery’ to which OFLs, ABCs, and TACs are annually specified
- Species formerly managed in a complex of ‘other species’ now managed separately as ‘in the fishery’ and individual OFLs, ABCs, and TACs annually for each species
- ‘Ecosystem Component’ (EC) identified as a separated category under the FMP for which neither annual assessments nor specifications (OFL/ABC/TAC) are necessary. Species under the ‘Forage Fish’ category and all Prohibited Species are all managed under this EC category.
Additional changes to FMP including primarily housekeeping modifications to comply with the revised requirements. These include:
- Identifying that Annual Catch Limits (ACL) are established under the FMP and set equal to existing ABCs. FMPs already contained an ABC Control Rule thus this modification was merely to comply with revised terminology.
Note: The analysis which accompanied this amendment package (EA) estimated the buffer levels (OFL:ABC) associated with target species under a range of tier levels for the existing ABC control rule employed in the North Pacific. This control rule includes a kink at BMSY which then constrains catch as biomass declines < BMSY. This important feature of North Pacific groundfish management provides for automatic rebuilding when stocks are below their target size. By definition, under the NPFMC tier system, the ABC < OFL and accommodates the uncertainty in OFL that the ACL provisions were designed to address. Under the Tier 1 control rule the uncertainty in the OFL (as measured by the probability density function around the point estimates of the OFL) is directly employed to calculate the maximum ABC. For all other tiers the ABC Control rule results in a conservative buffer below OFL, with the lowest information tier (Tier 6) employing a straight 25% buffer on the OFL to accommodate uncertainty in ABC-setting.
- Accountability Measures (AM) were identified and referred specifically to the existing NMFS in-season management authority and existing protocols for when TACs, ABCs, and OFLs are exceeded and resulting management measures. This was simply a clarification to note that AMs are already in existence for groundfish in the North Pacific.
For more information:
BSAI Crab FMP
The primary change to the Crab FMP was the specification of an ABC control rule (where ACL=ABC) to account for the estimated uncertainty in the OFL. Secondary change was to specify that all 10 crab stocks were “in the fishery” and thus require specification of OFL and ABC (note that under the Crab FMP TAC-setting is delegated to the State of Alaska). Final change was to establish Accountability Measures for crab stocks in the case that an ACL is exceeded.
ABC Control Rule for Crab Stocks
The amendment analysis presented multiple options for setting an ABC control rule for crab stocks. The two primary approaches employed either a fixed buffer approach (whereby ABC is set at a fixed percentage below OFL) and a variable buffer approach (whereby the calculated buffer varies on both the calculated estimated uncertainty in the OFL and a risk decision (P*) on the relative probability of being below the OFL). The analysis (EA) which accompanied this amendment package calculated the varying risks of overage based on estimated ranges in the uncertainty of the estimates of the OFL for a range of crab stocks over a range of P* values and the short-and long-term implications of this on crab stocks. The Council chose to use a variable buffer approach for the Tiers for which biomass information for crab stocks is available (Tiers 1-4) and a fixed buffer approach for the Tier for which only catch information is available (Tier 5). The Council selected a P*=0.49 which was below the required 0.50 for Tiers 1-4 and a fixed buffer of 10% for Tier 5 as a maximum ABC (maxABC) control rule.
Due to the proximity of the calculated maxABC to the OFL (whereby ABC ~ OFL for Tiers 1-4) in combination with concerns on the inter-annual volatility in crab stock biomass and the amount of uncertainty in crab stock assessments, the SSC has never employed the maximum ABC in any year since this ABC control rule was implemented. Instead, the SSC has recommended a range of fixed buffers below maxABC based upon the estimated uncertainty in the OFL for each stock. These buffers have ranged from 10-75% (below OFL) since implementation of the ABC control rule in 2011.
Accountability Measures (AMs) for Crab Stocks
The AMs specified for Crab stocks are such that any overage of the ACL will be accounted for by a downward adjustment to the TAC for that species during the fishing season following the overage.
For more information: https://alaskafisheries.noaa.gov/sites/default/files/analyses/finaleaamds38-39.pdf
The primary changes to the Scallop FMP to comply with the new ACL and AM requirements were the following:
- Weathervane scallop designated as ‘in the fishery’ with requirements for annual OFLs and ABCs (where ACL = ABC). Note that under delegated management guideline harvest levels (GHLs) are established by the State of Alaska.
- All non-weathervane (and non-target) scallop stocks were moved to an Ecosystem Component category where specifications are not required.
- An ABC Control rule was established where ABC = 90% of the OFL (and ACL = ABC).
- The OFL for statewide scallop stocks was redefined to include all sources of mortality.
- Accountability measures (AMs) were established such that the State of Alaska will set the annual GHL by management region sufficiently below the ACL (which is established statewide) such that the sum of the estimated discard mortality in directed and groundfish fisheries as well as the directed harvest does not exceed the ACL. Should the ACL be exceeded, the overage will be accounted for by a downward adjustment to the GHL during the fishing season following the overage.
The analysis (EA) which accompanied this amendment package estimated the relative risks of a range of fixed buffer values as well as the re-estimation of the OFL to include discard mortality during the time frame for which the OFL is estimated (based on average catch).
For more information: https://alaskafisheries.noaa.gov/sites/default/files/analyses/amd13ea0911.pdf
- A Decision-Theoretic Approach to Setting Buffers Between Fishery Management Targets and Limits (revised)
- Definition of Risk Aversion
- A general method to adjust catch limits/targets with survey uncertainty
- Addressing scientific uncertainty when making fishing level recommendations to avoid overfishing
- Probabilistic approaches to setting catch levels
- ACL Powerpoint Stram/DiCosimo
- ACL Powerpoint Jernigan
- Determining the Vulnerability of stocks Powerpoint (Spencer)
- Control Rules and Uncertainty Powerpoint (Methot)
- Revisions to the NS1 Guidelines Powerpoint
- What do we need for simple P* PPT (Hanselman)
- Using Survey Uncertainty to set ACLs PPT (Hanselman)
- Probability based catch levels PPT (Shertzer)
- Decision Theoretic Approach PPT (Thompson)
- ACL PPT (Thompson)
- Scallop ACL Compliance Issues PPT (Stram)