A group of Lake Norman fishermen is asking the federal government to order Duke Energy to install an oxygen-injection system in a part of the lake near McGuire Nuclear Station in Huntersville to help prevent mass summer fish kills.
Members of the Norman Fishery Alliance wrote the Federal Energy Regulatory Commission in Washington, D.C., recently seeking to make such a system a condition of Duke Energy's renewal of its Catawba River hydroelectric license. The alliance has more than 200 members.
The fishermen cited the 3,000 dead striped bass found floating on the surface in summer 2004 and the estimated 100 stripers that died in summer 2009 when dissolved oxygen levels dropped below survivable levels for the fish.
They also cited what they called the worst known kill to date: the estimated 7,000 dead adult striped bass removed from the lake by state and Duke Energy biologists in July and August.
"This kill was of such a magnitude that the stench of decaying and dead fish was disgusting when the wind was not blowing," longtime Lake Norman fishing guide Gus Gustafson wrote to the federal commission in late October. "The odor was so pungent that fishermen and boaters in the kill zone gagged for fresh air at times."
"We've lost thousands of our best friends," longtime Lake Norman fisherman and alliance member Sam Newman said in an interview last week.
In a September letter to Newman, who had written Gov. Bev Perdue for help, Brian McRae of the N.C. Wildlife Resources Commission blamed this summer's fish kill on a natural phenomenon that occurs only in deeper reservoirs such as Lake Norman and Badin Lake, which lies in Rowan, Stanly, Davidson and Montgomery counties.
"Because of the depth of these reservoirs, deep isolated pockets of dissolved oxygen form during the late spring and early summer, only to collapse as dissolved oxygen levels decrease through the summer," wrote McRae, the commission's Piedmont fisheries regional supervisor.
"Although this stratification occurs annually, we are still assessing the specific conditions that result in striped bass mortality in some years, but not others, and how to address these conditions in the future," McRae wrote.
While oxygen-injection systems are options to help prevent future striped bass kills, McRae said, paying for such a system in a poor economy "is difficult to justify at the scale needed at Lake Norman."
Installing such systems has cost the Tennessee Valley Authority from $600,000 to $2million, and annual operating costs are from $600,000 to $900,000, McRae wrote. The systems send liquid oxygen from large containers on shore into pipes that disperse the oxygen in the water.
FERC spokeswoman Celeste Miller said letters such as those from the fishermen become part of the public record the commission will consider in Duke's relicensing, although nothing has been decided as to their specific request for an oxygen-injection system.
Duke spokesperson Erin Culbert said oxygen-injection systems will be among the topics to be discussed by the Lake Norman Advisory Committee on Tuesday. The committee includes Duke environmental scientists, representatives of the state Wildlife Resources Commission and others.
But Culbert also noted that this summer's kill was the result of a natural occurrence that also struck other Piedmont reservoirs, including ones with no power plants.