Posted: April 3, 2024

Penn State researchers discover a one-of-a-kind fish

Photo credit: Robert Criswell

Photo credit: Robert Criswell

In an attempt to rescue a rare darter in the lower Susquehanna River, a Penn State research team, working with the Pennsylvania Fish and Boat Commission, has determined that the fish is a distinct subspecies found nowhere else. And that makes the effort to restore its population even more important, the researchers say.

A yellow- to olive-colored member of the darter family with dark bars often arrayed in zebra fashion, the Chesapeake logperch (right) is typically just a few inches long. It is believed only ever to have inhabited the lower drainages of the Susquehanna and Potomac rivers, and it has not been seen in the Potomac since the late 1930s.

To reach their conclusion that the Chesapeake logperch, Percina bimaculata, is one of a kind, the researchers collected thousands of specimens of logperch using seines, electrofishing units and electrified benthic trawls from the Allegheny River, from tributaries of Lake Erie and from the lower Susquehanna River.

The study, published in the journal Fishes, also included specimens from the Mississippi River drainage that were collected in Illinois and Minnesota and stored at the Illinois Natural History Survey.

To compare the fish from the different populations, researchers made 18 measurements and seven counts on specimens, quantifying characteristics such as the presence or absence of scales on the fishes' nape.

"We concluded that the Chesapeake logperch found in the lower Susquehanna River and a few of its tributaries is not the same as closely related fish found in the other drainages," said team leader Jay Stauffer, distinguished professor of ichthyology at Penn State. "That makes our project to rescue and reintroduce the fish into the river and tributaries even more urgent."

—Jeff Mulhollem