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The application of a Precautionary Approach establishes a framework in which fishery managers, scientists, and users of the resource contribute in different ways to the achievement of specific management goals. While fisheries managers have the primary responsibility in the definition of a management strategy, there are clear implications regarding the role of scientific research in this process. The implicit obligations of scientists are to determine the status of stocks relative to limits and targets, to predict the outcomes of management actions for reaching the targets and avoiding the limits, and to characterize the uncertainty in both of these.

Scientists should assist in the evaluation of potential management strategies. Data collection, biological research, and stock assessment are integral parts of fishery management strategies. The links between these should be explicitly incorporated into the evaluation of alternative management strategies. It is also incumbent on the scientists to assist managers in prioritizing the research investment to reduce existing uncertainties. Once implemented, management strategies should be regularly re-evaluated to assess their effectiveness in achieving management goals and to determine whether they portray accurately the risks associated with management actions.

Communication between scientists, managers, and users of the resource is an important component in the Precautionary Approach. While the exact form of that communication will depend on circumstances, the principles of transparency, information content, and simplicity should be considered when developing communication channels.

The appropriate characterization of uncertainty, in terms of both precision and accuracy, is one of the main research implications of the Precautionary Approach. There are potentially large uncertainties in the inputs to assessment models and in the results of those models. It is essential that those uncertainties are taken into account in stock assessment by incorporating realistic levels of model complexity and/or consideration of alternative hypotheses. This is a complex task and there is a need for continuous research to improve and develop the mathematical techniques for doing this.

In addition to quantifying these uncertainties, scientists and managers should develop strategies to reduce uncertainty in stock assessments through appropriate data collection and research. Although the details of these strategies will depend on the stock under consideration, there are areas of important research for most of the stocks of tunas and tuna-like fishes.

For several those stocks information on key biological parameters is lacking. The impact of this is to increase the uncertainty of the stock assessments. Increased research effort is necessary in several areas, such as validation of age and growth, determination of stock structure, estimation of mixing rates, estimation of the effects of climate on the movements and recruitment of tunas and tuna-like fishes, and description of their habitats.

Active, multidisciplinary, well-coordinated research on FADs is necessary to investigate the impacts of FADs on the movements and behaviour of the tunas and other species that are attracted to the FADs. In addition, it is necessary to better understand the influence of FADs on pelagic ecosystem structure and dynamics. This research should be conducted with at-sea surveys, experiments using instrumented or common FADs, and detailed data obtained from purse seiners and FAD supply vessels.

Improved and routine assessment of the movement patterns of tunas is required. In particular, research is needed to determine how these relate to environmental variability (diffusive and advective, vertical, and horizontal movements). This recommendation applies to most stocks of tunas and tuna-like fishes worldwide. Large-scale, scientifically-designed tagging programs remain the basic tool to obtain a wide range of critical biological information.

Application of the Precautionary Approach also implies consideration of the ecosystem. Both the U.N. Fish Stocks Agreement and the FAO Code of Conduct refer to the need to conserve aquatic ecosystems. However, the notion of conserving aquatic ecosystems is poorly, if at all, defined. More effort should be devoted to express this management goal in an operational way.

Scientists can assist in defining operational objectives for ecosystem management. Empirical studies are needed to: (1) to describe the structure of pelagic ecosystems, (2) delineate the boundaries of pelagic ecosystems, and (3) to determine the trophic dynamics of a range of ecosystems. Using the results of those studies, ecosystem indices should be identified and estimated and ecosystem models improved. International multidisciplinary cooperation among scientists interested in pelagic ecosystems is an essential element in developing this area of research.

Research on new technology and/or novel uses of existing technology can improve our ability to collect data and reduce the impacts of tuna fisheries on the ecosystem. For example, automatic onboard camera systems may be useful to evaluate the species and sizes discarded, and remote sensing data could be used to predict areas of high concentration of associated juveniles and/or by-catch species. Improvement of sonar and/or sounder equipment could lead to a precise identification of size and species before setting. Development of escapement devices for unwanted species, such as escapement grids for small tunas and devices to reduce seabird mortality, could reduce the mortalities of those species.

In the absence of good data, accurate scientific assessments are problematic, and uncertainty is greater. The data available for assessing the fisheries for tunas and tuna-like fishes vary considerably both in quantity and quality. While deficiencies in data programs are recognized and there are ways to improve those data, there are no universal solutions, and management agencies need to carefully determine their research requirements, which, in turn, determine the priorities for data collection.

Not all current data collection programs provide complete and precise sets of data for assessments of stock status. Attempts should be made to increase the coverage and improve the quality of the data and, at the same time, to quantify, to the extent possible, the uncertainties associated with the data.

Deliberate illegal, unregulated, and unreported (IUU) fishing is a major cause of uncertainties in estimating total catches, and reduction of IUU fishing is the solution to this problem. In addition, reluctance or incapacity of national authorities to collect and share available data on IUU fishing with RFBs adds uncertainty in reported total catches, which must be solved at the RFB level.

Other problems in statistics are generally associated with inadequate data coverage and data quality, attributable to lack of good logbook systems and/or sampling systems. For example, the sampling system must be capable of providing data for accurate estimations of the species compositions of the catches. Problem areas, including incomplete records of the catches and biased sampling, and the corresponding solutions, are identified in detail in the section on data collection. In general, increased data coverage and higher quality of the data must be achieved by the national organizations and the RFBs, but also through collaboration among the RFBs, by establishing proper sampling programs, increasing logbook coverage, and increasing observer coverage.

More attention should be paid to designing data collection systems that would reduce the uncertainties associated with effort data.

Estimates of by-catches are presently lacking. To collect these data, well-designed scientific observer programs are required. These programs not only provide data on the amount and composition of the by-catches, but also information that can be useful in identifying factors affecting by-catch, thus leading to identification of possible mitigation measures. Observer programs also provide data for use in tracking changes in fishing efficiency, such as changes in the operations of the fleets or the deployment of new technologies, for which current logbook and sampling information may not provide sufficient information.

There must be recognition by national organizations of the requirements of the RFBs for maintaining confidential data, and the need for a significant improvement in the availability and sharing of existing data among national organizations, including those of non-member States, and RFBs (e.g. catch and effort data at fine temporal and spatial resolutions to compute indices of abundance).

Increased participation by the industry in this process would be of considerable value, for example, in proposing alternative hypotheses regarding various biological processes, assisting in the interpretation of fisheries data, planning data collection activities, and developing technological innovations to reduce the by-catches. As the Precautionary Approach allows more precise management as the overall uncertainty decreases, there is an additional incentive for the industry to participate in information-gathering activities.

For the implementation of a Precautionary Approach, it is required only that scientists provide their best scientific assessment of the uncertainties related to the status of the resource. However, all parties involved in the management of a resource should work toward reducing the existing uncertainties to the greatest extent possible in order to minimize risks and increase the benefits to be derived from the resource.

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