Application of multiattribute utility analysis in determining coho salmon policy

Graduation date: 1982Policy decisions in fishery management are becoming increasingly\ud complex and difficult. This is especially true for the salmon fisheries\ud where policy outcomes affect the productivity of the salmon\ud resource and the subsequent well-being of commercial fishermen, charter\ud boat operators, Indian fishermen, and sport anglers. The objective\ud of this study was to advance methodology from statistical\ud decision analysis which would assist fishery managers in Oregon who\ud must make particularly difficult choices with respect to allocation\ud and production of coho salmon while recognizing uncertainties in the\ud environment, incomplete state of knowledge, and the conflicting needs\ud and desires of different interest groups.\ud The method chosen given multiple objectives and uncertainty is\ud multiattribute utility analysis. The approach consists, of two main\ud components: (1) a computer model which simulates the life cycle of\ud hatchery and stream spawning coho salmon given environmental variation,\ud different hatchery juvenile release levels and harvest rates;\ud and (2) an objective function which relates the different outcomes\ud from alternative release levels and harvest rates to an assessment\ud of the degree to which individual objectives are met.\ud The approach was used to evaluate and rank the expected outcomes\ud from twelve proposed policies under different hypothesized ocean\ud environments. Analysis of the results suggest that (1) the most\ud effective policy is achieved with a relatively low harvest rate and\ud high smolt release level; (2) selection of a particular harvest rate\ud is the most important decision variable; and (3) a large smolt release\ud level can be maintained unless such releases adversely decreases the\ud ocean survival of stream spawning coho.\ud Because the coho fishery is a mixed stock fishery consisting of\ud hatchery and wild stocks, the results suggest that too high a harvest\ud rate will lead to depletion of wild stocks, considered important because\ud of their potential contribution to production and diverse genetic\ud traits and characteristics. Conversely, too low a harvest rate\ud will lead to excessive escapement of coho and thus reduce the total\ud catch.\ud As is illustrated, formulating the coho decision problem in a\ud multiattribute utility analysis framework is useful in two ways.\ud First, by quantifying the objectives of the decision maker, consistent\ud results from following alternative policies can be determined.\ud These results provide a basis for comparison and serve as a guide for\ud decision making involving uncertainty. Second, the approach is\ud useful in isolating major objectives and conflicts, value judgments,\ud trade-offs, and needed empirical evidence