Despite mortalities from a bacterial infection, the relative abundance of juvenile bass on the Susquehanna and Juniata rivers is estimated to be 25 percent above the long-term average for the system according to data compiled by the Fish and Boat Commission.

As part of an ongoing review of the potential causes and effects of an unusual outbreak of columnaris disease among juvenile smallmouth bass that occurred over the summer, the PFBC compared nearly two decades worth of population survey data from across the Susquehanna River basin.

This year biologists recorded an average of 8.6 young of the year (YOY) smallmouth per 50 meters surveyed. That figure is higher than the 19-year average of 6.9.

Smallmouth bass typically require 3-4 years to reach a legal size. While it will therefore take some time for the 2005 YOY to reach the size range that recreational anglers target, the presence of a strong year class is encouraging news for the future.

Heavy springtime flows have contributed to poor year classes four of the last five years. It is believed this low reproductive success is now translating into an overall decline in adult bass abundance for the Susquehanna and Juniata rivers. PFBC biologists will conduct a special inventory of adult smallmouth bass later this fall to document the current population structure.

The Commission continues to work with partners such as the Department of Environmental Protection, the U.S. Fish and Wildlife Service, the United States Geological Survey and the Susquehanna River Basin Commission to compile and analyze data that might help better explain why pockets of young smallmouth contracted columnaris disease in early summer.

The Commission intends to hold a public forum on smallmouth bass in the Susquehanna basin sometime over the winter.

9/16/2005