Through combined physical and chemical surveys of water properties, as well as biological sampling, along the Washington-Oregon-California coast in August 2011, this study showed that large portions of shelf water were corrosive to pteropods. A strong correlation between aragonite saturation state and pteropod shell dissolution is shown. It is estimated that the incidence of severe shell dissolution in pteropods, due to anthropogenic OA, has doubled in near shore environments since pre-industrial conditions, and this is expected to increase. The results show that pteropod habitat suitability is decline in the California Current Ecosystem. Observed impacts represent a basline for futre observations.