01-7539. Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Greater Amberjack; Overfished Fishery

AGENCY:

National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.

ACTION:

Determination of overfished fishery.

SUMMARY:

NMFS has determined that the Gulf of Mexico greater amberjack fishery is overfished and has notified the Gulf of Mexico Fishery Management Council (Council) of related responsibilities under the Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens Act).

DATES:

Effective March 27, 2001.

FOR FURTHER INFORMATION CONTACT:

Phil Steele, telephone [phone], fax [phone], e-mail [e-mail].

SUPPLEMENTARY INFORMATION:

The Gulf of Mexico reef fish fishery is managed under the Fishery Management Plan for the Reef Fish Resources of the Gulf of Mexico (FMP). The FMP was prepared by the Council and approved and implemented by NMFS under the authority of the Magnuson-Stevens Act. The FMP is implemented by regulations at 50 CFR part 622.

Determination of Overfished Fishery

NMFS’ determination of the status of a stock relative to “overfishing” and an “overfished” condition is based on both the removal of fish from the stock through fishing (the exploitation rate) and the current stock size. When the exploitation rate jeopardizes the capacity of a stock to produce its maximum sustainable yield (MSY) on a continuing basis, overfishing occurs. The exploitation rate (i.e., rate of removal of fish from a population by fishing) is usually expressed in terms of an instantaneous fishing mortality rate (F). Another important factor for classifying the status of a resource is the current stock level. If a stock's biomass falls below its minimum stock size threshold (MSST), the capacity of the stock to produce MSY on a continuing basis is jeopardized, and the stock is said to be in an overfished condition. Refer to NMFS' National Standard Guidelines for further information regarding these terms and concepts (final rule issued May 1, 1998; 63 FR 24212).

NMFS has made a determination regarding the status of the Gulf of Mexico greater amberjack stock relative to overfishing and to an overfished condition based on the 2000 greater amberjack stock assessment conducted by NMFS' Southeast Fisheries Science Center and on the December 2000 Report of the Council's Reef Fish Stock Assessment Panel (RFSAP). These most recent analyses indicate that the stock is overfished but is not undergoing overfishing due to presumed recent reductions in F. The NMFS' stock assessment used a calibrated Virtual Population Analysis (VPA) to obtain estimates of population abundance and mortality rates based on data through 1998. Inputs to the assessment were obtained from the following sources: Data on catch-at-age and selectivity; an index of abundance from private vessels and charter boats; and indices of abundance from the headboat and handline fisheries. Sensitivity analyses included (a) examinations of various combinations of the three indices for tuning; (b) truncation of the time series for the three indices to a period in which size limits were generally constant; (c) examination of alternatives for the F ratios for the terminal age group (fixing or estimating F); (d) two alternative stock-recruitment relationships; and (e) several assumed levels of natural mortality (i.e., 0.15, 0.25, 0.35).

Based on all the stock assessment options presented, the RFSAP chose four options for further consideration. These four options comprised best available scientific advice to the Council; all four combinations indicated that the greater amberjack stock was overfished in 1998 based on the Minimum Stock Size Threshold (MSST) status determination criterion. The best estimate of stock size in 2000 showed that the stock is at less than one-half of MSST. The assessment results also indicate that reductions in fishing mortality are required to eliminate overfishing. The assessment, however, did not take into account recent (1998) management actions that the RFSAP believes are adequate to achieve the required reductions in F. The RFSAP recognizes that the most recent (as of 1997) estimates of F will not reflect any effects of the closed season (started in 1998), greater amberjack bag limit, and bag and size limits presently in place for lesser amberjack/rudderfish (often mistaken for greater amberjack). If these recently instituted measures have reduced fishing mortality for greater amberjack as expected, then this resource is no longer experiencing overfishing.

Section 304(e) of the Magnuson-Stevens Act requires that within 1 year of being notified of the identification of a stock as being overfished, the affected Regional Fishery Management Council must develop measures to end overfishing and rebuild the stock. On February 9, 2001, the Acting Regional Administrator, NMFS Southeast Region, notified the Council of the overfished status of the Gulf of Mexico greater amberjack and requested that the Council take appropriate action. The letter to the Council reads as follows:

Ms. Kay Williams, Chairman

Gulf of Mexico Fishery Management Council

3018 U.S. Highway 301, Suite 1000

Tampa, Florida 33619

Dear Kay:

This is to inform the Council that, based upon the best available scientific information, the National Marine Fisheries Service (NMFS) has determined that the Gulf of Mexico greater amberjack stock is overfished but is not experiencing overfishing.

This determination is based on the 2000 greater amberjack stock assessment conducted by the Southeast Fisheries Science Center and the December 2000 Report of the Reef Fish Stock Assessment Panel (RFSAP; copies enclosed). These most recent analyses indicate that the stock is overfished but is not undergoing overfishing due to presumed recent reductions in fishing mortality (F). The NMFS assessment used a calibrated VPA to obtain estimates of population abundance and mortality rates using data through 1998. Inputs to the assessment were obtained from data on catch at age and selectivity, from an index of abundance from private vessels and charter boats, and from indices of abundance from the headboat and handline fisheries. Sensitivity analyses included examination of various combinations of the three indices for tuning, truncation of the time series for the three indices to a period in which size limits were generally constant, examination of alternatives for the F ratios for the terminal age group (fixing or estimating F), examination of two alternative stock-recruitment relationships, and an examination of the assumed level of natural mortality (0.15, 0.25, 0.35).

Based on all the assessment options presented, the RFSAP chose four combinations for further consideration that comprised the best available advice to the Council. All four combinations indicated that the greater amberjack stock was overfished in 1998 based on the Minimum Stock Size Threshold (MSST). The best estimate of stock size in 2000 showed that the stock is at less than one-half of MSST. The assessment results also indicate that reductions in fishing mortality are required to eliminate overfishing; however, the assessment did not take into account recent (1998) management actions that the RFSAP believes are adequate to achieve the required reductions in F. The RFSAP panel recognizes that the most recent (as of 1997) estimates of F will not reflect any effects of the closed season (started in 1998), greater amberjack bag limit, and bag and size limits that are presently in place for lesser amberjack/rudderfish (often mistaken for greater amberjack). The stock, therefore, is no longer experiencing overfishing if these recent regulations have reduced fishing mortality as expected.

The reference points for overfishing and overfished currently in the Fishery Management Plan for the Reef Fish Resources of the Gulf of Mexico are based only on fishing mortality rates expressed as spawning potential ratios (overfishing: 30% static SPR; overfished: 20% transitional SPR). These reference points are not fully compliant with the national standard guidelines because they do not include a component based on stock size and, thus, are not an adequate basis for determination of stock status. The national guidelines require specification of a minimum stock size threshold (MSST) and a maximum fishing mortality threshold (MFMT). The 2000 stock assessment includes estimates of these status determination criteria as well as an estimate of MSY.

The Magnuson-Stevens Fishery Conservation and Management Act requires that the Council propose management measures to initiate rebuilding of the stock within one year of the determination that the stock is overfished. The 2000 stock assessment and the December 2000 RFSAP Report provide the Council with a range of assessment and rebuilding scenarios. As the Council addresses the overfished status and rebuilding of the greater amberjack stock, the Council must develop a plan to rebuild the stock to the biomass at maximum sustainable yield (MSY) and must select specific estimates of MSY, optimum yield, MFMT, and MSST as part of this plan. Clearly, the Council has already considered this at the January meeting when it voted to use the RFSAP's Table 6 as a basis for a rebuilding plan, if they were informed by NMFS that such a plan is required. We will be happy to assist the Council in future development of this rebuilding plan.

Please note that the most recent 2000 Report to Congress on the Status of Fisheries of the United States will list the status of amberjack as neither overfished nor approaching the overfished condition. Unfortunately, our determination of an overfished status for the Gulf greater amberjack stock was not completed in time for inclusion in the 2000 Congressional Report but will be included in the 2001 Report.

I look forward to working with the Council to develop a plan for rebuilding the greater amberjack stock.

Sincerely yours,

Joseph E. Powers, Ph.D.

Acting Regional Administrator

Enclosures

Dated: March 21, 2001.

William T. Hogarth,

Acting Assistant Administrator for Fisheries, National Marine Fisheries Service.