HARRISBURG - The Department of Environmental Protection (DEP) has released a work plan outlining what it says are "intensive efforts" to continue studying and sampling dozens of locations in the Susquehanna River basin throughout 2013. It will include analysis of water quality, water flow, sediment, pesticides, hormones, invertebrates, fish tissue and other areas of study. Portions of the study will focus on areas of the river or its tributaries where smallmouth bass reproduce.

DEP Secretary Mike Krancer said DEP will work with the Fish and Boat Commission, the Susquehanna River Basin Commission and the U.S. Geological Survey (USGS).

Last May, the Fish and Boat Commission asked DEP to designate the main branch of the Susquehanna River impaired so additional scientific studies could be done to determine the cause of a major decline in smallmouth bass. DEP said there wasn't sufficient evidence yet to list a nearly 100-mile stretch of the Susquehanna from Sunbury downstream to the Holtwood Dam as impaired.

The smallmouth bass has been hit with outbreaks of bacterial infections periodically since 2005, fish commission biologist Geoff Smith said at the time. He said one theory holds that poor water quality is compromising fishes' immune systems and making them vulnerable to bacteria. Connections to Marcellus shale drilling have been suggested.

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

Krancer said in his statement, released Friday, that the "actual cause or causes of the issues" with smallmouth bass have not yet been determined or linked to any particular water quality issue.

"But DEP is dedicated to working with our partners to find the answer," he said.

Sunbury, elsewhere

The agency's sampling efforts will be focused on sites along the Susquehanna at Marietta, City Island and Sunbury and along the Juniata River at the Lewistown Narrows and Newport. A site along the Delaware River near Trenton, N.J., will be used as a control site. Staff will test for various water quality parameters, like dissolved oxygen, temperature and pH, at multiple sites in the Susquehanna. Samples of fish, mussels and macroinvertebrates, such as mayflies, will also be collected.

"Our efforts span the entire watershed," Krancer said. "Sampling across the Susquehanna River basin allows us to identify and accurately measure the effects of various influences on the river. This research will provide data and help us decide what next steps, if any, are needed to protect our waterways."

Fish tissue from bass collected during spawning season will be analyzed for pesticides, PCBs and metals. DEP will also work with the USGS to analyze fatty tissue from healthy and diseased fish to determine the effects of different environmental factors.

In the coming weeks, DEP will sample for pesticides at existing water quality network stations along the Susquehanna, Juniata and Delaware rivers. Samples will be collected during some rain events, as that is when pesticides and herbicides are more likely to wash into the river.

DEP will analyze the samples for 54 different compounds. The study also calls for analysis of sediment samples and in-stream monitoring data, to be collected at spawning areas, that examines for pesticides and hormonal compounds. Staff will also take water quality samples from 32 sites in the tributaries of the Susquehanna River basin to better characterize the entire watershed.

The agency's biologists continue to consult with a contracted algal expert to analyze samples collected in areas where young-of-year bass have died off or where algal blooms have occurred in the past. Water samples from algae-heavy areas will be analyzed for total suspended solids, ammonia, nitrogen and phosphorus to determine the relationship between nutrient run-off, or discharges, and algae growth. Excessive algae may be indicative of poor water quality and can inhibit aquatic life and recreational activity, such as fishing.

DEP continues to wait for final approval from the U.S. Environmental Protection Agency of its final 2012 Integrated Waters report, a biannual assessment of the state's rivers and streams required by the federal Clean Water Act. The report describes the health of various waterways in the state and, where needed, DEP proposes listing waterways as impaired.

On the Net: www.dep.state.pa.us (click on the "Susquehanna River Study Update" button on the homepage).