Annual Fish Study
Studies of fish in the Nine Mile Run stream date back to the 1940s, when one identified no fish in the stream. Numerous additional studies were conducted by the Pennsylvania Fish and Boat Commission, U.S. Army Corp of Engineers and others before the restoration; nearly all showed very meager or nonexistent aquatic life in the stream.
UpstreamPgh began monitoring fish after the completion of the restoration in 2006. Each year, an electrofishing survey is led by Dr. Brady Porter and Dr. Beth Dakin of Duquesne University with students from local universities. The process uses an electrified probe to shock the water and slightly stun the fish in order to collect and catalog them before returning them to the stream.
By collecting data on the quantity and variety of fish species, researchers see changes in the watershed ecosystem over time. Certain varieties of fish like Spotfin Shiners are considered pioneering species, meaning that they are one of the first to inhabit polluted water. These surveys allow researchers to determine which species are pioneers and therefore more pollution tolerant.
The fish survey is one of the clearest markers of the improved habitat in Nine Mile Run. There are now dozens of species in the portion of the stream below Commercial St, and 7 to 10 different species are found in the reach above the culvert at Commercial St. The fish are now so numerous that Dr Brady and his team have had to reduce the size of the survey area in order to complete it in one weekend.