A “perfect storm” of stressors is destroying one of the best smallmouth fisheries in the nation. Algae blooms, bacteria, viruses, parasites, and pollutants annually decimate young-of-the year bass, leaving the Susquehanna River with a steadily declining number of big fish and little recruitment to replace them.
Since the first disease outbreak in 2005, biologists with the Pennsylvania Fish and Boat Commission (PFBC) have been studying the problem on the river that flows from Otsego Lake in Cooperstown, N.Y., to Chesapeake Bay, draining about half of the state’s land area. Their conclusion: The problem is too complex for them to solve without additional help.
“That’s why we’re trying to convince the EPA (U.S. Environmental Protection Agency) to put the Susquehanna on the (impaired waters) list,” said John Arway, PFBC executive director.
Despite the Susquehanna’s biological and recreation impairment, the state Department of Environmental Protection decided not to include the river on the list, forcing the PFBC to look elsewhere for help.
“We’ve also had meetings with our members of Congress,” Arway said. “This is extremely important. If the river goes on the impaired list, then there’s a time clock to fix it. But that clock doesn’t start until the problem is formally recognized.
"Putting it on the 303D list would mean that there’s a plan and we’d be eligible for grant money and we could prioritize how to spend it.”
The PFBC has support from the U.S. Fish and Wildlife Service for its campaign. In a letter to the EPA, Region 5 Director Wendi Weber wrote the following:
“We concur with recent scientific assessments that indicate a chronic problem exists with recruitment of smallmouth bass in the river.
“We are also concerned with the recent rise in reported skin lesions on bass, as well as emerging evidence of inter-sex, possibly caused by endocrine disruption compounds in the water. The Service believes the suite of warning signs exhibited by the smallmouth bass population is cause for careful and thorough assessment of environmental conditions in the river. While exact linkages and root causes seem to remain unclear, we believe the evidence suggests that environmental stressors are affecting the biota in the river.”
And just how much have those environmental stressors impacted smallmouth bass? “We’d typically get 1 ½ to 2 good years for every 1 bad year (of reproduction). Now, we will be lucky if we get 1 out of 8,” said Geoff Smith, a biologist who has studied the river.
He added that the number of adult fish in the river “has plateaued to low densities historically.”
“As the older fish die of old age, we’re not seeing the recruitment we need to replace them,” Arway said
He points to dissolved phosphorus in the river as a “principal stressor.” Right at the time bass are born, he added, “We’re seeing blooms of nuisance algae from the west shore to the east shore.”
That results in low dissolved oxygen, which in turn, compromises the immune system of young bass.
“We need to trace it (phosphorus) to the source,” Arway said. “We need to know where it comes from. That’s why we need to be on the 303D list.”
Additionally, biologists have identified these contaminants in the river that could cause endocrine disruption:
Thirteen flame retardant compounds, 2 personal care products (triclosan), 14 organochlorine pesticides, and 9 other pesticides.
They’ve also confirmed Largemouth Bass Virus.
“That’s not likely a factor (for abundance). But just carrying that virus might add to the stress,” Smith said.
Possibly most disturbing, though, is that similar problems with smallmouth recruitment now have spread into the Susquehanna’s tributaries and even outside of the basin, to the Allegheny and Delaware.
Anglers, meanwhile, “were madder than a hornet’s nest for a time,” Arway said. That’s because the PFBC implemented mandatory catch-and-release for the middle 98 miles of the Susquehanna and prohibited targeting of bass on nests from May 1 to June 15.
“But now they understand and they’re behind us. They’re working with us,” the PFBC executive director added.