Coupling Recreational Fisheries and Phosphorous to Estimate Impacts of Nutrient Loadings on Freshwater Fishing Demand and Value

Nutrient pollution can lead to eutrophication, algal blooms, and degradation of valued ecosystem services such as fishing, yet reducing nutrient loads from non-point pollution sources such as agriculture remains challenging. Deriving the demand for ecosystem service benefits from reduced nutrient loadings requires an integrated understanding of how the value of ecosystem services depends on loadings. Ecological production functions were estimated to relate abundance of several key sport fish to phosphorus loadings at thousands of lakes and streams in Michigan. These species-specific spatial abundance models were then linked to recreation fishing demand. The demand model uses data on fishing trips and locations collected via mail surveys from 2008 to present. The demand model relates angler behaviors (species sought, number of trips, and fishing locations) to the distances and the abundance of fish at the sites. The resulting integrated models linking phosphorous loading to fishing behaviors inform economic estimates of fishing benefits resulting from water quality improvements due to reduced nutrient loads, and provide predictions of how patterns of fishing across the landscape would change in response to reduced nutrient loads, which can inform efforts to manage fisheries and facilitate policies reducing non-point source pollution.