Statements by the Marine Fisheries Section include:
- 1997 MFS Statement on Bluefin Tuna
- 1998 MFS Statement on North Atlantic Swordfish
Marine Fisheries Section 1997 Statement on Bluefin Tuna
The Marine Fisheries Section (MFS) of the American Fisheries Society has been monitoring the stock condition and management of Atlantic bluefin tuna closely since at least 1991. Several statements have been issued over this time period by the MFS, which have expressed our concern over the status of the western Atlantic stock and in which we have suggested what we, as professional fishery scientists, believe is appropriate action to rebuild the stock.
In our first statement, released in May, 1992, we recommended, among other things, that a recovery plan and timetable be implemented immediately. In a subsequent statement released in July, 1995, we again stated that “the immediate priority is to define a biologically acceptable recovery target and establish and implement a stringent timetable for rebuilding the stock to this target level. Until such time as the rebuilding plan is implemented by ICCAT and the question of spawning site fidelity is resolved, the MFS believes that quota increases are inappropriate and that the current quota should be maintained or reduced.”
At the 1995 meeting of the International Commission for the Conservation of Atlantic Tunas (ICCAT) the commission approved the following resolution: “That the SCRS develop, at its 1996 meeting, separate and distinct recovery options for each of the western and eastern Atlantic bluefin tuna management stocks, taking into account the possible effects of mixing that may occur; and the SCRS should calculate a series of annual total allowable catches (TACs) based on stock projections that are needed for rebuilding the western and eastern management stocks, respectively, to levels which would support MSY, within selected alternative recovery time periods and with intermediate goals and milestones along the path to rebuilding. Therecovery options shall be based on the 1996 stock assessments for each management stock. The selected alternative recovery time periods shall be 10, 15 and 20 years, with a 50% probability.”
The MFS viewed this action by the commission as a positive and decisive step towards the ultimate recovery of the western Atlantic stock of bluefin tuna. This action, combined with recent ICCAT resolutions authorizing aggressive trade restrictive measures to ensure compliance by both member and non-member nations, was generally recognized as a turning point in the responsiveness and effectiveness of ICCAT.
Recent ICCAT Actions
The results of the 1996 SCRS stock assessment and recovery projections indicate that a 50% probability of recovery to the MSY biomass level within even the most distant time horizon that the commission wanted to consider (20 years) would require a constant quota of no more than 500 mt. Despite this, the commission approved a quota increase of 150 mt to 2354 mt (2500 mt including discards), with the justification that this catch level is sustainable and that the spawning stock will show a gradual increase over a period of 20 years. However, the projections also indicate that, while there is virtually no chance that the stock will rebuild to MSY in 20 years, there is a significant chance that the spawning stock will continue to decline. While we recognize that these projections have a great deal of uncertainty associated with them, we believe that quota increases are risk prone and inappropriate considering our current understanding of the stock condition.
Bluefin tuna have been under some form of active management by ICCAT since 1974 when a minimum size was imposed. Thus, ICCAT has been managing bluefin for 23 years and the spawning stock is currently at or near its lowest level ever. With the current quota, the spawning stock is projected to increase slightly over the next 20 years, but only to about 25% of the target level after 43 years of management. The MFS believes that allowing the spawning stock to remain at such low levels for such a protracted period of time places the stock in serious danger of collapse. Therefore we conclude that the most recent action taken by ICCAT, increasing the quota and failing to define and implement a recovery target and timetable, is inconsistent with our previous recommendations and inappropriate considering the current understanding of the status of the stock.
Furthermore, the MFS notes that the question of spawning site fidelity remains unresolved, and again cautions that if bluefin tuna exhibit spawning site fidelity, then current spawning biomass estimates for the western Atlantic could substantially overestimate the true spawning biomass. The MFS stresses that transatlantic movement of fish in either direction reveals little information about spawning site fidelity unless the natal area of the tagged fish is known or can be inferred. Indices of abundance for the Gulf of Mexico, the principal west Atlantic spawning area, remain at very low levels, suggesting that the true west Atlantic spawning stock may be at substantially lower levels than indicated by the stock assessment.
The MFS again urges the ICCAT commission to maintain or reduce the quota until such time as a rebuilding plan is implemented and the question of spawning site fidelity is resolved.
Steven A. Berkeley
Hatfield Marine Science Center
2030 Marine Science Drive
Newport, OR 97365
Marine Fisheries Section 1998 Statement on North Atlantic Swordfish
Atlantic swordfish and other highly migratory tunas and tuna-like species are the management responsibility of the International Commission for the Conservation of Atlantic Tunas (ICCAT). Despite the statutory mandate of ICCAT to maintain stocks at their level of maximum sustainable yield, North Atlantic swordfish have been overfished for at least 10 years, and the population continues to decline. This statement is issued by the Marine Fisheries Section of the American Fisheries Society to express our concern for the condition of this resource and to urge the ICCAT member nations to adopt effective, risk-averse management measures that will allow the stock to rebuild in a reasonable time period.
Three stocks of swordfish are currently recognized in the Atlantic Ocean: North Atlantic, South Atlantic, and Mediterranean. While all three stocks are considered overfished, this statement addresses only the North Atlantic stock. For management purposes, the North Atlantic stock is separated from the South Atlantic stock at 50 N latitude. At least 28 countries have reported swordfish landings from this stock in recent years. However, Spain, US, Portugal, Japan, and Canada account for more than 90% of the total reported landings. Spain and the US alone landed 67% of the total catch in 1995.
The principal gear in this fishery is the pelagic longline, which accounts for more than 95% of swordfish landings in the North Atlantic. Most of the catch is taken by longlines specifically targeting swordfish, but significant numbers are also caught as a bycatch in tuna longline fisheries.
Total reported North Atlantic swordfish landings peaked at 20,224 mt in 1987, and have since declined to between 14,000 and 17,000 mt. Despite stock assessments as early as the mid-1980s that indicated the stock was in rapid decline, it was not until 1990 that ICCAT recommended management measures for swordfish (to take effect in 1991). These recommendations were: 1) to reduce fishing mortality on fish weighing more than 25 kg by 15% from 1988 levels. 2) to restrict the landing of swordfish weighing less than 25 kg to no more than 15% of the number of swordfish per vessel landing. 3) for countries not targeting swordfish, to limit the incidental catch of swordfish to no more than 10% of their total catch by weight. A subsequent stock assessment indicated that these management measures had not been effective in stemming the decline, and in 1994, ICCAT recommended individual country quotas for the principal harvesting nations: Spain, US, Canada, and Portugal. In 1995, recognizing that rebuilding would take at least several years, percentage shares were established for the major harvesting nations. Individual national quotas were henceforth to be determined by applying that nation’s percentage share to the total allowable stock-wide catch (TAC). In addition, ICCAT established harvest penalties for member nations that exceed their quota, and trade sanction provisions for non-compliance by non-member nations.
Status of the Stock
The 1996 stock assessment, the most recent conducted by ICCAT, indicated that North Atlantic swordfish have continued to decline unabated despite management measures imposed since 1991. By 1996, the assessment estimated that the stock had declined to 58% of the level required to produce MSY. Fishing mortality was more than twice the level consistent with MSY (if the stock was capable of supporting MSY, which it is not), and 3.5 times higher than the more conservative F0.1 fishing mortality target. The assessment further estimated that the 1995 catch (plus discards) of 16,934 mt exceeded replacement yield (the amount of catch that could be taken without causing further stock declines) by more than 5,500 mt, ensuring continued, rapid stock declines.
Current Management Regime
There are two principal management measures in effect for North Atlantic swordfish: a minimum size and country-specific quotas. The minimum size regulation has been disregarded by virtually all countries except the US. However, even in the US, the effectiveness of the minimum size is limited, because the vast majority of swordfish caught on longlines are dead when brought alongside the vessel. Although there may have been some reduction in fishing mortality on small fish as a result of the minimum size, the impact of this measure has been primarily to change small fish landings into small fish discards, most of which are dead. Since discards are not counted against the quota, the minimum size actually results in an increase in fishing mortality on larger fish with minimal decrease in mortality of smaller fish.
Quotas have not been effective because those recommended by ICCAT have consistently exceeded replacement yield, resulting in continued stock declines. Additionally, many smaller harvesting nations (both member and non-member) have actually increased their swordfish catches in recent years, further increasing the rate of decline. Projections made in 1996 estimate that simply arresting the decline would require a catch of no more than about 10,000 mt. Despite this, annual quotas recommended by ICCAT for 1997, 1998, and 1999 were set at 11,300 mt, 11,000 mt and 10,700 mt, respectively. Thus, even if this measure has 100% compliance by both member and non-member nations, the stock will continue to decline. By the time quotas are again reviewed in 1999, replacement yield can be expected to be less than 10,000 mt. And, with the stock at a lower level, rebuilding within any reasonable time period (e.g. <10 years) will require a TAC well below this level. Conclusions
The Marine Fisheries Section concludes that the ICCAT management regime for North Atlantic swordfish has not been effective. The stock has been in constant, monotonic decline since about 1980 and has been overfished since at least 1988. Management measures currently in effect will not even stem the decline, even if perfectly implemented. Current management measures are inconsistent with ICCAT’s objective of maximum sustainable yield, as well as internationally accepted principals of risk-averse fishery management. Therefore, we strongly recommend that ICCAT take the following minimum actions to rebuild this valuable resource:
- At the 1998 ICCAT meeting, the TAC for 1999 should be reduced to no more than 10,000 mt.
- All sources of anticipated mortality must be realistically projected for both member and non-member nations, and quotas set accordingly such that total stock removal (including dead discards) does not exceed 10,000 mt in 1999.
- At the 1998 meeting, ICCAT must implement a biologically acceptable recovery target and a stringent timetable for rebuilding the stock to this level. The minimum acceptable recovery target is Bmsy (the stock size capable of producing MSY), and the maximum acceptable time frame for recovery is 10 years. This recovery plan should be implemented no later than the year following the 1999 stock assessment. The TAC for 2000 should not exceed the estimated replacement yield for that year. Intermediate targets should be established to monitor recovery, and management measures adjusted as necessary to ensure that stock recovery will be achieved within the established time frame.
- ICCAT must ensure that management measures developed to achieve the above recovery target are effective. Should subsequent assessments indicate that the recovery is not following the anticipated trajectory because of non-compliance, then ICCAT must aggressively pursue its already approved trade sanctions to ensure compliance.
Steven A. Berkeley
Hatfield Marine Science Center
2030 Marine Science Drive
Newport, OR 97365
September 2, 1998