The Great Miami River’s Scaled Inhabitants

Every place has a story and  the inhabitants are the ones that tell that story. Natural places and the species that exist in those places are no different; such is the case of the fish found in the Great Miami River. In Southwestern Ohio, sits a roughly 165  mile long tributary of the Ohio River, called the Great Miami River. The Great Miami River watershed flows through 10 counties and drains 3,802 square miles of land, going through both Dayton and Cincinnati (Figure 1). The river currently goes through 15 metropolitan areas of the region.

The Great Miami river has suffered floods, extreme physical alterations and pollution, affecting the fish species that are able to live in it. After the 1913 floods devastated both Dayton and Cincinnati, the Miami Conservancy District would be created in 1915 and begin the building of levees and retention basins (See Image 2 for a snapshot of what this river looks like). Pollution also became a huge issue, especially as people were flushing prescription medications and birth control pills down their toilets. Medications in the water meant that there were higher levels of certain chemicals, such as progesterone, which can cause male fish to develop half-formed eggs, instead of fully-formed sperm, created reproduction issues in certain species. Fish which were more tolerant of pollutants (and were often not native to the area), became more populated in the Great Miami, while native fishes struggled.

Over the last 100 years, some levees have been removed, and thanks to Ohio EPA (Environmental Protection Agency) water quality research, policy, and enforcement, the Great Miami River has seen some improvement in water quality. Starting in 2008 and going through 2010, the Ohio EPA began surveying the Great Miami River, starting in Dayton and going the roughly 80 miles dowstream to the mouth of the Ohio River. One way that surveys were done was by doing electrofishing. This is a method where an electric current is sent through the water, not to kill the fish, but to stun them. Once the fish have been stunned, the researchers can easily collect and identify species before releasing them.

 

Some fish that are common in the Great Miami River are smallmouth, largemouth and spotted bass, white and rock bass, sunfish, and channel and flathead catfish. While pollutant-tolerant species may be in decline and native fish are definitely present, according to the Ohio EPA, as of 2012, 72% of the sites tested in the Great Miami River watershed failed to meet bacteria water quality standards; this is probably due to failing septic systems and agricultural use. And while the Great Miami River, itself and some of its tributaries showed good quality, overall, many of its western tributaries exhibited boor quality. The fish present and their population sizes can help to determine the threshold for pollutants in this stream system. When pollutants and turbidity (the amount of suspended sediments in the water which lead to water being “murky”) are kept in check, fish populations will remain successful and continue to be present for locals to enjoy for viewing and fishing.