Experimentation and Adaptive Management

Fisheries are large-scale perturbations that provide the opportunity for experimentation at time and space scales that would never be supported by any of the usual funding agencies. The need for experimentation and some of the difficulties inherent in experiments with marine fisheries have been described elsewhere (e.g., Larkin 1972; Pikitch 1988; McAllister and Peterman 1992; Policansky 1993a, 1993b). Indeed, the oft-repeated advice to use adaptive management (e.g., Walters 1986; NRC 1996a, 1996b) is advice to take an experimental approach, one in which the management regimes are designed to facilitate data collection and—even more important—hypothesis testing. Thus, the management plan evolves as hypotheses are either supported or rejected. Indeed, the discussion of rights-based allocation schemes above makes clear how important experimentation is, both in the natural and the social sciences.

In many cases, fishing has been going on for so long that experiments are difficult because the results have already occurred (e.g., Policansky 1993a, 1993b; Auster et al. 1996). But sometimes a long history of fishing can be an advantage when an unplanned perturbation occurs. For example, when World War II forced a cessation of fishing in the North Sea, the long data set allowed a careful analysis of its effects (Beverton and Holt 1957, Rijnsdorp 1992). Not surprisingly, there was a large increase in many fish populations.

Marine protected areas also can provide a great deal of information on the effects of fisheries, environmental fluctuations, and other factors on fishing if they are implemented adaptively (see, e.g., the study of Polovina and Haight [in press] described above). That requires that carefully designed monitoring programs accompany the implementation of protected areas. Similarly, the introduction of new fishery regulations, such as bycatch-reduction devices or turtle-excluder devices, provides opportunities for developing and testing ecological ideas as well as learning about the effects of fishing and the effectiveness of fishery management.

Deliberate experimentation with a public resource or profits is not lightly undertaken (Policansky 1993b) because there are risks involved. One is that adaptive management can take a very long time to mature into a successful program (Walters et al. 1993). Another is that populations or ecosystems could be adversely affected by experimental overfishing. But the committee presumes that the need for useful information in general outweighs the risks, although the latter must be carefully considered. For the Bering Sea, the NRC actually recommended deliberate overfishing in restricted areas as a way of gaining information about the ecosystem (NRC 1996a), and this committee agrees that useful information could be gained in that way if experimental fishing is carefully controlled.



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