Science which cuts its way through the muddy pond of daily life without mingling with it casts its wealth to the right and left, but the puny boatmen do not know how to fish for it.
Although the committee believes that the 1997 Northeast groundfish stock assessments were sufficient and appropriate for providing scientific input to management decisions, the following recommendations are suggested to improve the quality of information and advice.
Improve the collection, analysis, and modeling of stock assessment data as detailed in Chapter 3. Such improvements could include evaluations of sample size, design, and data collection in the fishery and the surveys; the use of alternative methods for data analysis; consideration of a wider variety of assessment models; and better treatment of uncertainty in forecasting;
Improve relationships and collaborations between NMFS and harvesters by providing, for example, an opportunity to involve harvesters in the stock assessment process and using harvesters to collect and assess disaggregated catch per unit effort data;
Continue to educate stock assessment scientists through short-term exchanges among NMFS centers so that each center can keep abreast of the latest improvements in stock assessment technologies being used at other NMFS fishery science centers, and at other organizations in the United States or elsewhere;
Ensure that a greater number of independent scientists from academia and elsewhere participate in the Stock Assessment Review Committee (SARC) process; where necessary, pay competitive rates for such outside participation to ensure that a sufficient number of the best people are involved in the review;
Increase the frequency of stock assessments. As the New England Fishery Management Council intensifies its management of the Northeast fishery, stock assessments may have to be performed more frequently than every three years (the current timing);
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5 CONCLUSIONS Science which cuts its way through the muddy pond of daily life without mingling with it casts its wealth to the right and left, but the puny boatmen do not know how to fish for it. Alexander Herzen Although the committee believes that the 1997 Northeast groundfish stock assessments were sufficient and appropriate for providing scientific input to management decisions, the following recommendations are suggested to improve the quality of information and advice. RECOMMENDED ACTIONS Improve the collection, analysis, and modeling of stock assessment data as detailed in Chapter 3. Such improvements could include evaluations of sample size, design, and data collection in the fishery and the surveys; the use of alternative methods for data analysis; consideration of a wider variety of assessment models; and better treatment of uncertainty in forecasting; Improve relationships and collaborations between NMFS and harvesters by providing, for example, an opportunity to involve harvesters in the stock assessment process and using harvesters to collect and assess disaggregated catch per unit effort data; Continue to educate stock assessment scientists through short-term exchanges among NMFS centers so that each center can keep abreast of the latest improvements in stock assessment technologies being used at other NMFS fishery science centers, and at other organizations in the United States or elsewhere; Ensure that a greater number of independent scientists from academia and elsewhere participate in the Stock Assessment Review Committee (SARC) process; where necessary, pay competitive rates for such outside participation to ensure that a sufficient number of the best people are involved in the review; Increase the frequency of stock assessments. As the New England Fishery Management Council intensifies its management of the Northeast fishery, stock assessments may have to be performed more frequently than every three years (the current timing);
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Consider a wider range of scenarios (e.g., recruitment, individual growth, survival, substock structure, ecosystem, data quality, compliance with regulations, long-term industry response) in evaluating management strategies; Investigate the effects of specific management actions, such as closed area and days at sea limitations, on fishing mortalities and related parameters; Work toward a comprehensive management model that links stock assessments with ecological, social and economic responses and adaptation for given long-term management strategies. This involves input from the social sciences (economics, social and political science, operational research) and from a wider range of natural sciences (ecology, genetics, oceanography) than traditionally is the case in fisheries management. The committee has not explicitly considered the costs of implementing these recommendations, which may require either additional resources or a reprogramming of existing resources. CENTRAL ISSUES Adequacy of Scientific Information for Management Improving Fish Stock Assessments (NRC, 1998) reviewed the state of existing knowledge about the stock assessment process. The report stressed that the feedback between stock assessment and fisheries management has to be improved to manage fisheries more effectively. The report also includes nine recommendations pertinent to stock assessment. The committee examined these recommendations in relation to the Northeast fishery stock assessments, and concluded that most of the earlier report's recommendations are already being addressed by NMFS in these fisheries. The current stock assessment process, despite the need for improvements, appears to provide a valid scientific context for evaluating the status of fish populations and the effects of fishery management. Furthermore, the process is analogous to processes used in jurisdictions elsewhere in the world. Therefore, the Northeast stock assessment process is well within the standards of the stock assessments conducted elsewhere in the United States and by other nations. In all five stocks considered, fishing mortality was high, increasing and not sustainable, whereas spawning stock biomass was low and decreasing. The available data and the assessments using them show convincingly that the reviewed stocks have been subject to increased fishing mortality and decreasing spawning stock biomass through the 1980s and early 1990s. These conditions considerably increase the risk of major stock collapse. The increasing fishing mortality rates during the 1980s and 1990 indicate that management measures implemented during that period were ineffective in controlling fishing mortality. Therefore a different, more drastic approach was needed to decrease the probability of stock collapse. Justification For Management Actions Overall, the demonstrated tenuous status of the five stocks and the substantial uncertainty surrounding their ability to recover warranted strong management action. The committee finds no scientific basis to support assertions that the regulations imposed by Amendment 7 are too severe from a biological perspective. In fact, further management action may be necessary for the Gulf of Maine cod fishery. It should be added that the regulations in Amendments 5-7 might have been avoided if fishing mortality in the New England groundfisheries had been effectively controlled from the mid-1980s.
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If stock sizes are at intermediate levels relative to historical values, an argument might be made simply to maximize the yield from recruitment obtained. However, current scientific wisdom indicates that a precautionary approach should be used for harvesting unless there is conclusive evidence that higher harvests will result in better ecosystem regulation. When stocks are low, as in the Northeast, high fishing mortality markedly increases the risk of irrevocable stock damage. In two of the five cases in the Northeast (Georges Bank haddock and southern New England yellowtail flounder), the committee believes that the stocks already have collapsed, as indicated by low spawning levels combined with a period of little or no recruitment. Recruitment remains low and recent increases in biomass primarily result from higher survival of small year classes and growth of the current biomass because of the lower fishing mortality. For Georges Bank cod, yellowtail flounder, and Gulf of Maine cod, some of the committee's simulations of future stock size show that there would be a real danger of future stock collapse if strong regulations to reduce fishing mortality were not in place. For Gulf of Maine cod, the stock does not appear to have collapsed but there is danger it could under recent fishing mortality. Current regulations have not yet shown the ability to control fishing mortality for this stock. Additional management measures may be required. Effects of Management Regulations The assessments indicate that fishing mortality played a major role in reducing the abundance of groundfish in New England. Current stock assessments suggest that fishing mortality has been reduced for four of the five reviewed stocks and that these stocks appear to be increasing. The fifth stock, Gulf of Maine cod, has not experienced reduced fishing mortality, and it is not increasing. Biomass remains considerably smaller than observed in the past, and any relaxation of management measures may jeopardize sustained stock rebuilding. Sufficiency of Survey and Landings Data The scope and protocols of current data inputs (trawl survey and landing data) are sufficient for the stock assessments. Improvements in data collection systems are necessary, especially for catch and discard reporting, survey coverage, and collection of age information. Nevertheless, the assessment inputs are comparable to and, to some extent, better than those available for other stocks in the United States and elsewhere. The uncertainty of the stock assessments could be reduced further if the data inputs were improved. Usefulness of Stock Assessments as Predictive Tools There is no simple answer regarding the adequacy and reliability of these stock assessments as predictive tools. The current assessments evaluate how implementing different fishing mortalities (F), including no change in F, would affect the annual probabilities of reaching the rebuilding thresholds set by the New England Fishery Management Council. Future biomass trajectories can only be predicted in probabilistic terms, and there is great uncertainty about how long the stocks will take to rebuild to these thresholds. While NMFS forecasts do incorporate substantial uncertainty, some of the main sources of uncertainty have been left out. Knowledge of the biology of the fish stocks is incomplete, and this contributes to uncertainty in stock projections. For example, it is unclear whether changes in recruitment of young fish are environmentally controlled or the result of low spawning stock sizes. Different hypotheses about the relationship between stock abundance and subsequent recruitment are
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consistent with the data at hand, and they tend to push the time of recovery further out into the future. Under some of these hypotheses, the probability of the stock not having recovered to the Council thresholds, say within 10 years, is thus substantially larger than suggested by NMFS assessments. To estimate such probabilities quantitatively is not easy. It is therefore difficult to base the management decisions directly on predictions from stock assessments, without embodying the assessment and its predictions in a management strategy with precautionary qualities. Alternative Methods To Regulate Catch Technical measures, such as mesh size increases, were used extensively in the Northeast groundfish fisheries during the 1980s and early 1990s, and they did not succeed in limiting fishing mortality. Mesh size restrictions often do not lead to conservation of fish stocks unless fishing mortality itself is somehow controlled, for example, through setting a Total Allowable Catch (TAC) for the species, establishing closed areas, or limiting fishing effort. Increases in the closed areas appear to have played an important role in reducing fishing mortality in 1995 and 1996. The New England Fishery Management Council may choose to adjust mesh size and closed areas to fine-tune the control of fishing mortality. One problem with so-called technical measures is that they make it harder to quantitatively determine the effects of management actions on fishing mortality and stock size. A valuable role for future stock assessments will be to investigate whether and how the effects of these management actions on both fishing mortality and stock size can be measured. Factors Affecting Abundance of Stocks Evaluating the relative contributions of different factors in driving changes in the abundance of fish stocks is difficult, but as mentioned above, fishing mortality played a major role in reducing the abundance of the five stocks in the 1980s and early 1990s, and still does for the Gulf of Maine cod stock. The most recent estimates of fish mortality are the most uncertain, and assessments in future years may come up with much different estimates for 1995 and 1996. It should be noted that hydroclimatic changes have occurred in U.S. waters of the northwestern Atlantic, but their magnitude is substantially less than off Newfoundland and Labrador, where they are believed to be one of the causative factors in stock collapses. However, even if environmental changes were a factor affecting stock abundance, fishing mortalities were high enough to contribute to major stock collapses. To avoid stock collapse it is more important to stringently reduce fishing mortality during periods of adverse environmental conditions. Article 6.2 of the UN Agreement on Highly Migratory Fish Stocks and Straddling Fish Stocks (FAO, 1995) directs that: "States shall be more cautious when information is uncertain, unreliable or inadequate. The absence of adequate scientific information shall not be used as a reason for postponing or failing to take conservation and management measures." Further, Article 6.7 of this agreement specifies that: "If a natural phenomenon has a significant adverse impact on the status of [straddling fish stocks or highly migratory] fish stocks, States shall adopt conservation and management measures on an emergency basis to ensure that fishing activity does not exacerbate such adverse impact. States shall also adopt such measures on an emergency basis where fishing activity presents a serious threat to the sustainability of such stocks." Other Causes of Stock Fluctuations There is speculation among some interested parties that pollution and habitat destruction are reducing stock recruitment. If, in fact, these factors have affected recruitment (and there is
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no consensus in the scientific community), then this would not alter the scientific recommendation to reduce harvest levels. The fishing mortality recommended for stock rebuilding would need to be adjusted downward for decreased recruitment. Furthermore, if these factors are likely to continue for a long time, then it may not be possible to rebuild stocks to levels which occurred in the past. The larger issue of establishing a causal mechanism between stock fluctuations and environmental and pollution factors is a difficult one because all factors are changing at the same time and so their effects are confounded. However, future directed research on this area, involving environmental and ecosystem studies and cross-population comparisons of key stock-recruitment parameters, should be very valuable for constructing likely scenarios for policy evaluation. STOCK ASSESSMENT AND FISHERY MANAGEMENT The committee concludes that stock assessment science is not the real source of contention in the management of New England groundfish fisheries. Comments at a public hearing held by the committee support this conclusion. Many speakers suggested that the social and economic concerns created by strong management measures and lack of participation in the management process were the more important concerns. Traditional fishery science has a major role to play in fisheries management, but sound stock assessment clearly is not the only consideration. The New England Fishery Management Council will be facing critical decisions, depending on the recovery or nonrecovery of groundfish stocks. A long-term management strategy will be needed to decide the rate of rebuilding required to reach particular targets. Without sound stock assessment, targets and rebuilding rates cannot be set, nor can the effectiveness of the regulatory actions be measured. However, stock assessment in the narrow sense of estimating status and dynamics of fish populations is not sufficient for rational fisheries management. What constitutes a good management approach will vary over time, location, and components of the fish stock. To obtain the information necessary to design effective institutional and regulatory frameworks, it is essential that management draws on stock assessment, oceanography, ecology, economics, social and political science and operational research. Only when a more comprehensive approach is taken, with long-term management strategies based on data and insight from the various fields, properly accounting for the uncertainties surrounding data and theory, can fishery management provide for high continuing yield of food and health of stocks, while considering the needs of people dependent upon the fisheries.
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