The Effects of Water Quality on Coastal Recreation Flounder Fishing

This paper describes a bioeconomic model of a coastal recreational fishery that combines standard models of fish population dynamics, recreational catch, and recreation site choice. The population model estimates the influence of water quality on overall fish abundance through the effects of dissolved oxygen (DO) on the survivorship of young juvenile fish. The catch model estimates the influence of fish abundance and water quality on anglers’ average catch rates. The recreation demand model estimates welfare effects and changes in trip demand from changes in catch rates. The bioeconomic model also accounts for the feedback on the fish population through changes in the overall harvest pressure in the recreational fishery on the fish stock. The population model is specified using data on survival and reproduction from the fisheries science literature and government reports, and the model is calibrated using average historic recreational harvest levels in and out of the study area and historic commercial harvest levels for the entire fishery. The catch model is estimated using data on a sample of anglers who fished for summer flounder, data on water quality conditions from 23 water quality monitoring stations, and fishery-independent data on fish abundance collected in bottom trawl surveys, all in Maryland’s coastal bays in 2002. The recreation demand model is estimated using data from a stated choice survey of anglers who fish for summer flounder on the Atlantic coast. The bioeconomic model is used to estimate the aggregate benefits to recreational anglers from several illustrative scenarios of changes in water quality. The results indicate that improving water quality throughout the range of the species could lead to substantial increases in the fish population and associated benefits to recreational anglers from increased catch rates. Water quality improvements confined to Maryland’s coastal bays alone would have much smaller impacts.