Penn State Researchers Discover Unique Fish Subspecies, Highlight Urgency Of Conservation Efforts In Lower Susquehanna


A dock overlooks the Susquehanna River in Havre de Grace. (Credit: Van Fisher/ Patch)

HAVRE DE GRACE - Researchers from Penn State University recently uncovered a new subspecies of fish found only in the Susquehanna. The Chesapeake logperch was discovered during a research trip to rescue a rare darter fish near the Conowingo dam.

The Chesapeake logperch (Percina bimaculata), an olive or yellow-hued darter species marked with dark stripes, is typically just a few inches long and features a short, pointed snout and a small mouth. According to the research paper published in Fishies, the logperch is understood to have only dwelled in the lower basins of the Susquehanna and Potomac Rivers. Notably, it has been absent from the Potomac since the late 1930s.

The Chesapeake logperch [Percina bimaculata]. (Credit: Morphological Comparison of the Chesapeake Logperch Percina bimaculata with the Logperch Percina c. caprodes and Percina c. semifasciata in Pennsylvania/ Penn State University)

To establish the distinctive nature of the Chesapeake logperch, the research team gathered thousands of logperch samples. The specimens were collected from the Allegheny River, Lake Erie tributaries, and the lower Susquehanna River using seines, electrofishing units, and electrified benthic trawls. Samples from the Mississippi River drainage, stored at the Illinois Natural History Survey, were also included in the study.

Researchers compared different fish populations by making 18 measurements and seven counts on specimens, considering factors like the presence or absence of scales on the fish's nape and the number of pectoral fin rays, lateral-line scales, and gill rakers.

"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," team leader Jay Stauffer said in a University publication. "That makes our project to rescue and reintroduce the fish into the river and tributaries even more urgent."

While previous pollution has impacted the fish species, it is now threatened by invasive fish species, including the northern snakehead, flathead catfish, and blue catfish that have started populating the lower Susquehanna.

Chesapeake logperch populations are drastically declining in the river and some tributaries. It is already listed as endangered in Pennsylvania and Maryland, and its disappearance could spell a potential ecological crisis for the lower Susquehanna River.

In the Penn State publication, Stauffer warned that the Chesapeake logperch is on the verge of being added to the federal endangered species list, and further efforts are needed to study and reintroduce the fish.

"Few people realize how serious and pervasive the threat invasive predatory fish present to native benthic fish fauna," Stauffer said.

The research team recently completed a four-year project to restore the logperch population in the lower Susquehanna. The project, funded by nearly $500,000 in grants from the Pennsylvania Fish and Boat Commission and the Pennsylvania Wild Resources Fund, involved underwater snorkel surveys in parts of the lower Susquehanna and certain tributaries to capture Chesapeake logperch and identify their habitats.

According to the study, the team successfully bred and reared approximately 2,000 Chesapeake logperch in Penn State facilities and reintroduced the fish into suitable habitats within their historical range in the Susquehanna River drainage.

Although the Chesapeake logperch holds no commercial value and is not a sought-after recreational fish, it's still integral to the region's biodiversity. Stauffer told Penn State that its preservation is of utmost importance.

"If it goes extinct, we have lost another species that inhabits the Earth," he said. "I think there is something to be said for preserving the biodiversity of our aquatic systems. When a species goes extinct, it's gone forever. You don't get it back."

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