And here is another recent article. I just hope that after all the studies, there is some sort of follow thru.
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Susquehanna probe yields clues
By Deborah Weisberg
Southwest Correspondent
Wednesday, September 24, 2008 12:23 PM CDT
Harrisburg - A team of scientists has confirmed that low levels of dissolved oxygen are the culprit in smallmouth bass die-offs in the Susquehanna River.
"That's preliminary," said Kent Crawford of the U.S. Geological Survey, which partnered with the Pennsylvania Fish & Boat Commission and the Pennsylvania Department of Environmental Protection on the $392,000 study. "But we found the Susquehanna has a dissolved oxygen concentration of 4.0 milligrams per liter and normal levels are 5.0."
Although the state-federal field study ends Sept. 30, it will take months to process findings, said Crawford, who indicated that nutrient overload from as-yet unidentified sources contributed to low oxygen levels in the river.
Given the scope of the bass die-offs, which were massive during the hot dry summers of 2005 and 2007, scientists will be monitoring the river - once Pennsylvania's premier inland smallmouth fishery - for years.
That could be problematic, though, since the federal government will begin pulling the plug Sept. 30 on more than a dozen gauges used to monitor real-time flow, and at least one that also monitors water quality.
The U.S. Army Corps of Engineers recently announced it doesn't have enough money to run all 50 of its flood-forecasting gauges - at $15,000 each - and will cease operating 14. One - at Harrisburg - has been vital to the bass study, which focused on the river from Lewisburg on the West Branch to just downstream of Harrisburg around Steelton.
Looking to the future, Crawford was disappointed with the corps' move.
"Our monitoring for bass is critical during hot summer weather, so shutting off the Harrisburg gauge now won't directly impact the smallmouth study," he said. "But wouldn't it be nice if we could have year-after-year transmission of data, and ways to compare flow and quality in one part of the watershed with another?"
"Problems on the Susquehanna are not going to end anytime soon."
Large numbers of dead bass first surfaced during the hot dry summers of 2005 and 2007. Although identified as a bacterial infection known as Columnaris, the study group hasn't determined whether it was the primary cause of death or struck stressed fish opportunistically.
Low oxygen levels contribute to algae blooms - which have been widespread on the river. "That doesn't cause suffocation, but it can stress fish, and opens the door to Columnaris," Crawford said. "It's not as much a problem in higher flow where you get more turbulence and better transfer of oxygen from the air into the water.
"But in low flow, there's not as much turbulence and oxygen transfer from the air. Also, the amount of oxygen water can hold is dependent on water temperature - so, in low, warm water, the process gets worse on two counts," Crawford said.
This year's cooler weather and rainfall may explain why there were fewer dead bass, but that doesn't mean there isn't a systemic problem, said John Arway, the Fish & Boat Commission's environmental director. Monitoring flow helps scientists put pieces of the die-off puzzle together; the more data, the better, he said.
"Different parts of the basin experience different rainfall patterns. Not having all of the Corps' gauges fully functional is limiting, Arway said. "It would have been nice to be able to compare. I mean, that was the whole idea."
http://www.paoutdoornews.com/articles/2008/09/25/top_news/news03.txt
