The Economic Importance and Management of Mercury Contamination in Pelagic Fisheries

The presence of mercury in the U.S. fish supply is a growing public health concern. At high levels, mercury can be harmful to humans and ecosystems, and represents a growing threat not only to public health, but also to the economic and ecological viability of many fisheries. This research examined the economic issues surrounding mercury contamination in fish, developed a population dynamics and bioeconomic model to investigate the problem, and compared a variety of management actions to reduce consumer exposure to contaminants.The dissertation begins with an overview of contamination issues in U.S. fisheries, including a review of the historical public health impacts and their related economic costs. Management strategies for dealing with contamination were discussed, along with an examination of the efficacy of these actions and their implied economic cost to the fishing industry.Given that mercury concentration is shown to increase with fish length, this study examines the implications of harvesting smaller (and less contaminated) fish. This was accomplished through the development and application of an age-structured bioeconomic model for king mackerel, a species experiencing particularly large concentrations of mercury contamination. First, a population dynamics model of the Gulf of Mexico and Atlantic king mackerel stocks was constructed and validated. Using the population dynamics model as a base, a comprehensive bioeconomic model was created through the incorporation of the economic characteristics of the fishery and mercury contamination relationships. Forward simulations were used to examine the plausibility of different management alternatives for the king mackerel stocks in the presence of mercury contamination. The simulations demonstrated the possibility of reducing the amount of mercury that reaches consumers by altering the age composition of the commercially marketed catch. Furthermore, the simulations illustrated that it may be possible for this to occur without seriously impacting the long-run stability of the stock. There are tradeoffs, however, in terms of the economic viability of the fishery. In the case of both the Atlantic and Gulf stocks, reductions in mercury came at the price of reduced fishery profits and losses in the aggregate net present value of the fishery over a 25 year time horizon.