The ''Shenandoah National Park: Fish in sensitive habitats'' (SNP: fish) project. An integrated assessment of fish community responses to stream acidification.

The ''Shenandoah National Park: Fish in Sensitive Habitats'' (SNP:FISH) project is a response to declining pH and acid neutralizing capacity in Shenandoah National Park (SNP) streams. SNP receives more atmospheric sulfate than any other USA national park, and pH had decreased to the point where early negative effects on fish were expected. SNP provides the opportunity to study the early stages of acidification effects on fish. Three different classes of geological formations yield streams with low-ANC (0 mu Eq/L), intermediate-ANC (60-100 mu Eq/L) or high-ANC (150-200 mu Pq/L) waters in SNP. This allows a comparison of responses across a water quality gradient in a small geographic area receiving similar deposition. Both chronic and episodic acidification occur in SNP streams. Biological effects are apparent in fish species richness, population density, condition factor, age, size, and bioassay survival. A primary project objective was to provide the necessary data for development and testing models for forecasting changes in fish communities resulting from changes in stream chemistry. Monitored variables include several which are predictive of acidification effects on SNP fish communities.