Unique Fish Identified in Lower Susquehanna by Scientists

The lower drainages of the Susquehanna and Potomac rivers are known to have been the exclusive habitat of the Chesapeake logperch, which has not been sighted in the Potomac since the late 1930s. (Image Credit: Penn State)

The urgent need to preserve and rejuvenate the river’s fish population is being underscored by researchers.

A collaborative project between a research team at Penn State and the Pennsylvania Fish and Boat Commission is underway to protect a distinct darter from the lower Susquehanna River. Their investigations uncovered that this particular fish is a special subspecies not found anywhere else, highlighting the critical need to revitalize its numbers.

The Chesapeake logperch, part of the darter family and adorned with a yellow to olive color, often has dark patterns resembling zebra stripes. This small fish, typically only a few inches long, has a tiny mouth and a truncated, conical snout. Traditionally, its home has been the lower sections of the Susquehanna and Potomac rivers, but the fish hasn’t been seen in the Potomac for nearly a century.

By collecting thousands of logperch specimens from the Allegheny River, tributaries of Lake Erie, the lower Susquehanna River, and the Mississippi River drainage, researchers concluded that Chesapeake logperch, Percina bimaculata, is a singular species. This conclusion was drawn from 18 measurements and seven counts on specimens, looking at features such as the scales on the fishes’ nape, and the number of pectoral fin rays, lateral-line scales, and gill rakers.

Jay Stauffer, the team leader and distinguished professor of ichthyology at Penn State, stated, “The Chesapeake logperch in the lower Susquehanna River and a few of its tributaries is not the same as closely related fish in other drainages.” He further emphasized the vital importance of the project to rescue and reintroduce the fish into its native waterways.

Stauffer, along with his research group at Penn State’s College of Agricultural Sciences and Doug Fischer from the Pennsylvania Fish & Boat Commission, recently concluded a four-year restoration project funded by nearly $500,000 in grants. They focused on rejuvenating the logperch population in the lower Susquehanna, conducting underwater surveys and capturing Chesapeake logperch to determine their preferred habitats.

They managed to breed and raise around 2,000 Chesapeake logperch at Penn State facilities before releasing them back into their historical range in the Susquehanna River drainage. All the cultured fish were tagged for future identification.

Past pollution has taken its toll on the fish, and they now face threats from predatory invasive species like the northern snakehead and various catfish in the lower Susquehanna. Their numbers have significantly decreased.

Stauffer remarked on the serious threat that invasive predatory fish pose, and he stressed the urgency of action, as the Chesapeake logperch is close to being federally listed as endangered. Such a listing could have substantial impacts on development in the region. However, he expressed confidence in restoring the fish to its native habitat, though acknowledging it might require more time and effort.

Stauffer noted the uniqueness of this effort to save a species not yet federally listed. While questioning the worth of saving a fish without commercial or recreational value, he concluded that the loss of any species diminishes the Earth’s biodiversity.

Stauffer, aged 72, initially thought this would be his final research project but has now decided to continue working.

The complete study, titled “Morphological Comparison of the Chesapeake Logperch Percina bimaculata with the Logperch Percina c. caprodes and Percina c. semifasciata in Pennsylvania,” was published on May 27, 2023, in Fishes.

Contributors to this research included former graduate student Jonathan Freedman, Douglas Fischer of the Pennsylvania Fish and Boat Commission, and Robert Criswell, retired from the Pennsylvania Game Commission.

The U.S. Department of the Interior, U.S. Fish and Wildlife Service, Wild Resources Conservation Program, and U.S. Department of Agriculture’s National Institute of Food and Agriculture provided funding for this study.