Endocrine-disrupting compounds and herbicides, as well as pathogens and parasites, are the most likely causes for the decline of the Susquehanna River's world-class smallmouth fishery, according to results of a multi-year study by the Pennsylvania Department of Environmental Protection (DEP) and other agencies.
"We appreciate the assistance of the U.S. EPA (Environmental Protection Agency) and our other partners in the evaluation of many possible stressors to the smallmouth bass population . . . ," said John Arway, executive director of the Pennsylvania Fish and Boat Commission (FBC).
"The health of the smallmouth bass in the Susquehanna River continues to be compromised and this analysis rules out certain causes, prioritizes other uncertain causes for further study, and, most importantly, identifies likely causes which can be targeted for action."
TO FBC's credit, it has been sounding the alarm about fish with lesions and sores, as well as declining numbers, for years, as well as lobbied DEP to categorize the lower portion of the river as "impaired." That designation would allow for a comprehensive plan to be developed to address the problem.
Until the release of this study, though, DEP countered that it makes recommendations based on water quality, not species health, and refused to recommend that the Susquehanna be placed on the EPA's impaired waters list. Anglers and groups such as the Chesapeake Bay Foundation (CBF) hope that these findings will help the river get the help it needs.
"The time to start to remedy the sick Susquehanna River and save a world-class smallmouth fishery is now," said CBF's Harry Campbell. "An impairment declaration will start the healing process so that the waterway that millions of Pennsylvanians depend upon, and provides half of the freshwater to the Chesapeake Bay, can benefit from an unwavering level of restoration, resource investment, and pollution study."
Scientists now view temperature, dissolved oxygen, algal and bacterial toxins, and young-of-the-year food quality and habitat as "uncertain causes." Meanwhile, "unlikely causes" include high flows, ammonia, and toxic chemicals such as pesticides, PCBs, and metals.