BY DOYLE DIETZ
Recent publicity over black spots on small-mouth bass being caught in the Susquehanna River in the greater Sunbury area has caused great concern, but the phenomenon is not new or unusual, experts said.
There has been so much speculation about the irregular black blotches that the Pennsylvania Fish and Boat Commissioner (PFBC) issued a statement Wednesday confirming that similar spots have been previously observed on fish from other waters in the state and that the spots do not appear to harm the fish. In addition, because the spots are limited to skin discoloration, the fish are safe to consume under the state's general fish consumption guidelines, PFBC reported.
"The condition is commonly known as 'blotchy bass' or 'black spot' and has been documented occasionally in various Pennsylvania waters since as early as 1980," PFBC deputy director of operation Andy Shiels said. "In fact, in 1986, a nationwide survey found that the condition was present in 11 other states, including New York, Delaware and Maryland."
Former PFBC waterways conservation officer Mark Pisko, who used to be assigned in Northumberland County but now works in Berks and Schuylkill counties, said the situation has been known for about a decade.
"I'm not in the loop about what goes on up there like I once was, but I remember that bass with spots were being caught in the Susquehanna at least eight years ago, and it could even be 10 years ago," Pisko said Saturday while making his rounds on the opening day of trout season in the Southeast Region. "Our agency biologists monitor this very closely, but to tell you the truth, no one is really certain what causes the condition, but it seems there are plenty of theories."
As expected, those theories cover the gamut from the dumping of mine pollution to industrial waste into the river. More recently, the natural gas companies that are drilling throughout Pennsylvania have become the target of critics.
Condition is 'melanosis'
The PFBC started hearing from anglers late last year concerning the black spots, which most often are found on the head, lips, tail or fins. Melanin is a black pigment in the skin cells of fish and referred to by fisheries scientists as melanosis.
"It's not precisely known what causes the condition, but the bass that our biologists examined in previous years were generally healthy and in good condition," Shiels said. "While the appearance of these spots may be alarming, there is no harm to human health from consuming these fish."
Shiels added that the condition has not been linked to specific pollution events, nor is there any evidence to suggest that blotchy bass condition is related to the young-of-year small-mouth disease issues in the Susquehanna River and some of its tributaries that the PFBC and other agencies have been studying since 2005. PFBC biologists have documented the blotchy bass condition previously in Pennsylvania in the following waters:
Susquehanna River, 2011, 2006; Cowanesque Lake, Tioga County, 2003; Allegheny River, 1999; and Conneaut Lake, Crawford County; Presque Isle Bay, Erie County; Raystown Lake, Huntington County and several other waters, 1980s; and it was observed in New York's Hudson River during the 1980s, which resulted in a N.Y. fisheries biologist surveying other states about the condition.
According to several professional fishing guides on the Susquehanna River, who obviously have a vested interest in maintaining a healthy fishery, this condition occurs in bass even in the most pristine conditions. This was confirmed by Jim O'Brien of Minersville, who managed the Bass Pro Shops store in Harrisburg, who said that black spots have been observed on several of the fish in the store's aquarium, which he said is maintained to assure the highest water quality.