For Immediate Release
December 1, 2020
The Gulf of Mexico Fishery Management Council took final action on Reef Fish Amendment 48/Red Drum Amendment 5 which considers defining maximum sustainable yield (MSY), a maximum fishing mortality threshold (MFMT), a minimum stock size threshold (MSST), and an optimum yield (OY) for all managed stocks. These reference points are the basis for determining the health of each stock and are required under the Magnuson-Stevens Act and National Standard 1 guidelines. The list of stocks impacted by these recommendations are shown in the table below:
The maximum sustainable yield (MSY) is the largest, long-term average catch that can be taken from a stock or stock complex under prevailing ecological and environmental conditions, fishery technology characteristics, and the distribution of catch among fleets. A proxy is used when data are insufficient to estimate MSY directly. It’s important to know that lower MSY values allow for higher yield. However, higher MSY values are more resilient to natural variability before a stock is considered overfished. The Council recommends setting the goliath grouper MSY proxy at the yield when fishing at 40% spawning potential ratio (SPR); the red drum MSY proxy at the yield that provides for an escapement rate of juvenile fish to the spawning stock biomass (SSB) equivalent to 30% of those that would have escaped had there been no inshore fishery; and the MSY proxy for remaining species at the yield when fishing at 30% SPR (F30% SPR). The Council also recommends setting MSY proxy values in the future based on the yield produced by FMSY recommended by the Council’s Scientific and Statistical Committee and subject to approval by the Council through a plan amendment.
The maximum fishing mortality threshold (MFMT) is the rate of fishing mortality above which a stock is declared to be experiencing overfishing. It is important to know that MFMT may not exceed the rate of fishing associated with MSY. Additionally, the lower the MSY, the higher the MFMT can be because this assumes that fewer fish are required to produce the spawning output needed to achieve MSY. The Council recommends setting the MFMT equal to the fishing mortality at MSY for each stock.
The minimum stock size threshold (MSST) is the biomass level that a stock can decline to before being declared overfished and requiring a rebuilding plan. It cannot be lower than 50% of the stock biomass at MSY. As the MSST value increases, a higher minimum biomass is required for the stock to not be considered overfished. As the MSST value decreases a lower biomass is allowed. However, if a stock is overfished in this scenario it’s harder to rebuild. For stocks assessed across the South Atlantic and Gulf Councils’ jurisdictions (goliath grouper, mutton snapper, yellowtail snapper, and black grouper), the Council recommends setting MSST using existing definitions of MSST defined by the South Atlantic Council. The Council recommends setting the MSST = 0.75*BMSY for the remaining species. This MSST definition was recommended by the SSC as it allows some annual variability in stock size while reducing the likelihood of long rebuilding times that may result from lower MSST values.
The optimum yield (OY) is a level of harvest that will provide the greatest overall benefit to the nation. It is based on MSY reduced by any relevant economic, social, or ecological factors. It takes the protection of marine ecosystems into account and, in the case of an overfished fishery, provides for rebuilding to a level consistent with producing the MSY. It’s important to recognize that allowable harvest increases the closer OY is to MSY. The Council recommends setting the shallow-water grouper OY at 90% of MSY; setting the goliath grouper OY at zero consistent with the management approach for this species; maintaining the current OY for red drum; and setting OY at 90% of MSY for the remaining stocks.
The Council will submit these proposed changes to the Secretary of Commerce for approval and implementation.