The Standing Committee on Research and Statistics (SCRS) of the International Commission for the Conservation of Atlantic Tunas (ICCAT) has recently assessed the status of several key stocks of highly migratory species. The North Atlantic swordfish stock is nearly rebuilt (99% of Bmsy), a full three years earlier than anticipated. In order to maintain the North Atlantic swordfish stock at this healthy level, the Committee recommends maintaining the current total allowable catch.

The recent abundance trend for white marlin is slightly upward, while the trend for blue marlin is possibly stabilizing. However, these trends are based on only a few years of observations following adoption of the rebuilding plan in 2000; confirmation of these apparent trends in abundance will require at least an additional four or five years of data. The Committee advised that ICCAT should, at a minimum, continue the management measures already in place because marlins have not yet recovered. ICCAT should take steps to improve scientific data on dead and live releases of marlins, possibly by including an observer requirement. The Committee also recommended encouraging the use of circle hooks in fisheries where their use has been shown to be beneficial.

Assessment results for the Eastern Atlantic / Mediterranean stock of bluefin tuna indicate that the spawning stock biomass continues to decline while fishing mortality is increasing rapidly, especially for large fish. This is a serious concern since large spawners contribute more to recruitment success than medium-size spawners. Current fishing is expected to drive the spawning biomass to very low levels, with a high risk of stock collapse. SCRS recommended substantial reductions in fishing mortality and catch, indicating that catches need to be reduced to about 15,000 mt. The report suggested that closing Mediterranean fisheries during spawning season and increasing the minimum size to protect juveniles and fully enforcing that size limit might begin to reverse the decline and initiate recovery. Management actions are also needed to address overcapacity and illegal fishing.

The impact of changes in management measures in the eastern Atlantic on the western Atlantic stock and fisheries is potentially significant because of mixing. The assessment of western bluefin tuna continued to show no improvement in the stock. Changing management measures in the western Atlantic would probably have minimal impact on the eastern Atlantic, since the western fishery is small compared to the eastern Atlantic fishery.

Scientists from around the world participated in the development of this scientific advice. Because these fisheries are international in scope, with highly migratory stocks crossing national boundaries, fishing nations must work within ICCAT to reach agreement on appropriate conservation and management measures. The results of these stock assessments will be considered at the upcoming ICCAT annual meeting.

For more information, visit www.iccat.int.