The Ohio River Valley Water Sanitation Compact states that the Ohio River should support and maintain a balanced, diverse, and healthy ecosystem. To determine if pollution control efforts have achieved this objective, ORSANCO conducts biological assessments, which include three components; fish population and macroinvertebrate population studies, and a fish tissue contaminants program.

Biological Survey Results/Pool Reports

ORSANCO conducts biological surveys in different parts of the river each year.  The results of these surveys are available as reports that describe the status of the river in each of the focus areas.  These reports are currently based on the fish population data that is collected.  In the future, these reports will include additional data from macroinvertebrate studies.

Click here for survey/pool report results

Fish Consumption Advisories

Contact your state health department or natural resources/environmental protection agencies for current Ohio River consumption advisories.

Fish Population

Improvements in Ohio River water quality over the past 40 years have provided a cleaner River for aquatic life. Population data collected during ORSANCO’s yearly fish population studies evidences this progress. Electrofishing is the primary method by which fish are collected.

Fish Tissue Contaminants

Because many people consume their catch from the Ohio River, ORSANCO collects fish and examines the tissue for the presence of certain chemicals that may be harmful when ingested by humans. Yearly results are sent to the states bordering the River. If necessary, states will issue “consumption” advisories, which place limits on the type and amount of fish that can safely be eaten.


ORSANCO uses these small water-dwelling organisms as indicators of water quality; some require good, clean water to survive and reproduce.

Peer Reviewed Scientific Publications

Click here for a list of peer reviewed scientific publications