A Susquehanna River smallmouth bass was revealed on Monday by Pennsylvania authorities as having a malignant tumor.

An angler caught the smallmouth bass in November 2014 not far from Duncannon, and handed it over to the Pennsylvania Fish and Boat Commission (PFBC), agency officials said in a news release.

The image of the deformed fish has sparked pollution fears on social media.

Affected: The Pennsylvania Fish and Boat Commission said it discovered this fish has a malignant tumor. This fish was caught on November 3, 2014, PFBC officials said

Commenters on the PFBC's Facebook page, where the release and the image of the fish were posted, speculated on what caused the tumor. Several commenters pointed to waste materials being dumped into the river.

One commenter, who claimed to be an environmental consultant, wrote that the main factor might be herbicide from farmlands washing into the river.

University of Alberta ecologist Dr. David Schindler spoke to Men's Journal about the case, saying 'Such lesions and malformations are seen downstream of the oil sands, and downstream of superfund sites.

'They should be regarded as general indices of high industrial, agricultural and human pollution.'

King's College environmental program director Brian Mangan told Men's Journal 'One smallmouth bass from the Susquehanna River with a cancer is interesting, but in many ways it is scientifically meaningless [as a single data point].

'We do not know what caused this cancer in this fish.'

WNEP reported the PFBC is testing in the Susquehanna River where the fish was found.

PFBC's Rob Wnuk told the television station 'We have a group of biologists in the Harrisburg area and they have a testing protocol all set up. They're getting fish from anglers and from other methods and they're testing them that way.'

According to Stormwater PA, two of the Susquehanna River's pollution causes are phosphorus and nitrogen used as fertilizer and sewage treatment plant discharge.

Pennsylvania Department of Health's acting secretary Dr. Karen Murphy has said fish tumors do not pose a threat to human beings.

'There is no evidence that carcinomas in fish present any health hazard to humans,' Murphy said in a statement. 'However, people should avoid consuming fish that have visible signs of sores and lesions.'

PFBC officials said they've looked at Susquehanna River adult smallmouth bass for ten years. They said there have been sores and lesions on bass young.

The PFBC's news release said '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 [smallmouth bass] in Pennsylvania.'

The fish was caught in the middle of the river, agency officials said.

According to the PFBC, the agency has been trying for three years to get the Susquehanna River to be labeled by Pennsylvania's Department of Environmental Protection as one of the state's impaired waterways on a biannual list.

John Arway, the PFBC's executive director, said in a statement that 'The impairment designation is critical because it starts a timeline for developing a restoration plan.'

Struggle: According to the PFBC, the agency has been trying for three years to get the Susquehanna River to be labeled one of Pennsylvania's impaired waterways (file photo)

He added '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.'

The Washington Post noted the last list published in 2013 did not feature the Susquehanna River.

The Post pointed out a statement the EPA gave that year, saying 'Although we share the continuing concerns about the health of the smallmouth bass population, we do not have sufficient data at this time to scientifically support listing the main stem of the Susquehanna as impaired.'

Arden said in his Monday statement the fish with the tumor was caught in an area under catch-and-release regulations.

He also said '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.