Fish Population

Fish population studies have been a major component of ORSANCO monitoring activities throughout the organization’s history. In 1957, routine lockchamber surveys were initiated in cooperation with state and federal environmental and fisheries agencies. The methods employed, lockchamber size and structure, and sampling locations remained relatively unchanged throughout this 40+ year period. The data collected from these surveys comprise one of the largest, most comprehensive river fisheries databases in existence.

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

In 1990, ORSANCO added nighttime electrofishing to supplement lockchamber studies. Lockchamber sampling, while useful for providing valuable information, is very restrictive, as only 20 locks and dam facilities are located on the Ohio River for sampling. Because of this limitation, electrofishing has now become the primary method by which ORSANCO studies Ohio River fish populations.

Employing these electrofishing methods, ORSANCO focuses efforts on data collection for Ohio River biological criteria (biocriteria), development, and has conducted multiple intensive surveys in each of the 20 Ohio River pools.

For more information about ORSANCO’s Fish Population Studies, contact Rob Tewes.