Assessing Land Use, Land Cover, and Wastewater Infrastructure for Shellfish in the Puget Sound Nearshore

Abstract

Oysters, clams, mussels, and other bivalve mollusks are prized species of the Puget Sound estuary. Settling on the Puget Sound shores, shellfish play a critical role of filtering water, providing habitat, supporting local economic and recreational interests. While biological conditions for shellfish in the Puget Sound are some of the best in North America, every year shellfish beds and classified harvest areas are threatened and closed due to pathogens and toxins (WA DOH, 2008). Rapid landscape change associated with population growth and urbanization is known to be a major stressor on aquatic ecosystems including shellfish. Many previous studies link upland landscape changes with nearshore bacterial contamination. However, none examine the interaction between land use, land cover and wastewater infrastructure and their contribution on the impacts of urbanization on coastal environments. This study investigates how patterns of urbanization and forest cover interact with local wastewater to control pathogen loadings to shellfish harvest areas. To this end, I examine (1) what variables affecting shellfish vary across a gradient of urbanization and (2) what pattern metrics and wastewater treatments best predict water quality in Puget Sound nearshore environments that meet shellfish harvest standards.