HARRISBURG - The state Fish and Boat Commission wants a sister agency to designate the mainstream of the Susquehanna River impaired so additional scientific studies can be done to determine the cause of a major decline in smallmouth bass.

The decision is in the hands of the Department of Environmental Protection which says there isn't sufficient evidence yet to list a nearly 100-mile stretch of the Susquehanna from Sunbury downstream to the Holtwood Dam as impaired. A public comment period on the state's official list of impaired and threatened waters just ended.

Fish commission officials aired their concerns about the lack of a Susquehanna designation so far at a hearing last week before the Senate Game and Fisheries Committee.

The smallmouth bass has been hit with outbreaks of bacterial infections periodically since 2005, said fish commission biologist Geoff Smith.

He said one theory holds that poor water quality is compromising fishes' immune systems and making them vulnerable to bacteria.

In addition, anglers have caught bass with blotches on their skin this spring, said Smith. The fish are apparently healthy despite the blotches, he added.

The bacterial outbreaks have occurred during a period when the Susquehanna is affected by warm temperatures, high levels of dissolved oxygen, algae growth and contamination from pesticides and personal care products, the biologist said.

"Sick fish means we have a sick river," said commission executive director John Arway.

The commission has found no link with the health problems facing the smallmouth bass and Marcellus Shale drilling in the Susquehanna Basin, said commission spokesman Eric Levis.

But a House Democratic lawmaker is not shying away from drawing a connection.

Drilling activity contributes to the fragmentation of forest tracts, said Rep. Camille George, D-74, Houtzdale, ranking Democrat on the House Environmental Resources and Energy Committee.

"Given the fact that the majority of Marcellus development is taking place within the Susquehanna River Basin, it's not outlandish to believe the cumulative impacts to headwater and larger downstream waterways pose a risk of degradation," he said.

DEP officials said scientists from several agencies have been studying the lesions and sores found on smallmouth bass since 2007.

"The disease problems may be indicative of some stressor to the fish," wrote DEP Secretary Mike Krancer. "However, the disease is yet to be tied to any particular identifiable stressors. At this time the facts and science do not support placing the river on the (list)."

Krancer said studies of the smallmouth bass problem will continue regardless of whether the river is on the impaired list or not.

Meanwhile, a group of 22 retired DEP officials has called for the impairment designation.

"We maintain it is not necessary to know the source or cause of the impairment prior to listing," they wrote.

Senators on the panel differed in their assessments.

"We are not rushing to judgment," said panel chairman Richard Alloway, R-33, Chambersburg. "But we need to look hard at this."

State officials shouldn't let budget problems dictate their response to the problem, said Sen. Lisa Boscola, D-18, Bethlehem Twp.

Sen. Robert Robbins, R-50, Greenville, urged caution saying labeling an entire waterway as impaired can lead to higher local water and sewage treatment bills.

Contact the writer: rswift@timesshamrock.com