Pennsylvania Officials Confirm Rare Cancer in Smallmouth Bass


Officials from the Pennsylvania Fish and Boat Commission (PFBC) announced on Monday that laboratory results have returned for a single smallmouth bass caught in the middle Susquehanna River late last year. The fish, which was harvested by an angler and eventually delivered to the PFBC, had a large and unsightly growth on its lower lip. Tests results confirmed it to be a malignant tumor, the first of its kind ever seen in the state.

“Cancerous growths and tumors on fish are extremely rare in Pennsylvania and throughout the U.S., but they do occur. This is the only documented case of this type of tumor being found on SMB in Pennsylvania,” the PFBC stated in a press release. “The finding was confirmed by the U.S. Fish and Wildlife Service and the Aquatic Animal Health Laboratory at Michigan State University.”

Although the cancerous growth was only found on one fish, experts are concerned that it may mean that there is something in the water that is harmful to fish populations. Biologists have noted an increased occurrence of sores and lesions in young bass during spring and summer surveys, which is troubling even without the presence of tumors.

“As we continue to study the river, we find young-of-year and now adult bass with sores, lesions and more recently a cancerous tumor, all of which continue to negatively impact population levels and recreational fishing,” said John Arway, executive director of the PFBC. “The weight-of-evidence continues to build a case that we need to take some action on behalf of the fish.”

Nearly 100 miles of the Susquehanna River are already covered by catch-and-release regulations. Officials warn anglers fishing in other sections to avoid eating fish with obvious signs of illness, such as visible sores or lesions. According to Arway, sick smallmouth bass have been reported in the river since at least 2005, and may have led to a significant decrease in their population. For the past three years the PFBC has been petitioning the state’s Department of Environmental Protection to add the Susquehanna to Pennsylvania’s list of impaired waterways, but have so far it has been unsuccessful.

“The impairment designation is critical because it starts a timeline for developing a restoration plan,” said Arway. “We’ve known the river has been sick since 2005, when we first started seeing lesions on the smallmouth. Now we have more evidence to further the case for impairment.”

If the water quality continues to drop, Arway warned that the state could lose what was once considered a world-class smallmouth bass fishery.

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