Magnuson-Stevens Fishery Conservation and Management Act Reauthorized
Assessing Vulnerability - NMFS Vulnerability Work Group Preliminary Results
Assessing Vulnerability
NMFS has revised the guidelines for National Standard 1 (NS 1) of the Magnuson-Stevens Act, to comply with new annual catch limit and accountability measure requirements for ending overfishing in Federal fisheries as described in the Magnuson-Steven Reauthorization Act of 2006. Concurrently, several work groups (e.g., ABC/ACT Control Rules, Vulnerability Evaluations) have been created to produce reports on how to carry out the more technical components of the NS 1 guidelines.
The Vulnerability Evaluation Work Group (VEWG) was developed to provide a methodology for determining the vulnerability of a stock. While determining the vulnerability of a stock is not a requirement of the MSRA, NOAA Fisheries believes this information will be useful in meeting the new ACL requirements. The NS1 guidelines reference the term "vulnerability" in sections dealing with: 1) differentiating between stocks "in the fishery" and "ecosystem components"; 2) assembling and managing stock complexes; and 3) creating management control rules.
 Figure 1 |
 Figure 2 |
The Approach
Tasked with providing a tool that is flexible in its use and comparable across fisheries and regions, the VEWG reviewed several risk assessment methods to determine which approach was best suited for the NS1 guidelines use of the term vulnerability. The Productivity and Susceptibility Assessment (PSA) was selected as the best approach for examining the vulnerability of stocks, because it can be based on qualitative data, has a history of use in other fisheries, and is recommended by several organizations and work groups as a reasonable approach for determining risk.
The PSA was originally developed to classify differences in bycatch sustainability of the Australian prawn fishery by evaluating the productivity of a stock to its susceptibility to the fishery (Stobutzki et al. 2001). The productivity and susceptibility of a stock was determined by providing a score ranging from 1 to 3 for a standardized set of attributes (N=13) related to each factor. The scores were then calculated for each factor and graphically displayed on an x-y scatter plot (Figure 1). Stocks that received a low productivity score and a high susceptibility score were considered to be the least sustainable (i.e., high vulnerability), while stocks with a high productivity score and low susceptibility score were considered to be the most sustainable (i.e., low vulnerability).
Modifications to the Original PSA Methodology
While the VEWG agreed that the PSA was an appropriate model in which to base their vulnerability evaluation, the work group began meeting in January of 2008 to revise the methodology based on the proposed revisions of Hobday et al. (2004) and Rosenberg et al. (2007), as well as making additional revisions to provide more flexibility for its use in diverse U.S. fisheries.
Revisions include:
- Selecting an appropriate number of Productivity and Susceptibility attributes (Table 1 and Table 2);
- Redefining the scoring matrix to provide break points related to US fisheries;
- Developing a universal weighting system;
- Developing a Data Quality Index (Table 3; Figure 2); and
- Addressing different sectors and gear.
 Table 1 |
 Table 2 |
 Table 3 |
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Example Applications
The VEWG selected seven fisheries (i.e., Northeast Multispecies Groundfish, Atlantic Shark Complexes, South Atlantic/Gulf of Mexico Snapper-Grouper Longline Fishery, California Coastal Pelagics, California Nearshore Groundfish, Bering Sea/Aleutian Island Skate Complex, and the Hawaiian Pelagic Longline Fishery) to evaluate the effectiveness of its vulnerability evaluation. Overall 166 stocks were examined, and the results provided some interesting trends in vulnerability scores (Table 4; Figure 1). The work group is in the process of finalizing its report and expects to make it available to the public in April of 2009.
 Table 4A |
 Table 4B |
Tools and Resources
VEWG Preliminary Findings
VEWG Final Report – Available in ~ April 2009
Vulnerability Worksheet – Available in ~ April 2009
Graphing Software and Manual – Available in ~ April 2009
For more information, contact Wesley.Patrick@noaa.gov or call (301)713-2341.
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