Here is a copy of an artical that Bob Groene printed in the paper today.
This is part of the reason we are getting more and better
walleye”s here on pools 12-17
Cordova creating fish hatcheries using nuclear energy
Posted Online: Oct. 06, 2009, 9:00 pm
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Bob Groene, [email protected]
While reading, ponder these answers to two trivia questions that will come later in this column: question #1 answer is one and #2 is 6,000,000.
When the Quad-Cities Generation Station — Cordova nuclear Powerplant — was constructed many years ago, an on-site canal was constructed to handle the reactor”s cooling water before the water was returned to the Mississippi River. The canal didn”t work as well as planned, so an alternate design provided for the cooling water to be returned to the river underwater. To watch over any effects that the process may cause to the river, the plant has, among other activities, been monitoring the river fishery and adding to her swimming populations since the mid-1980s.
“There are two principle components to what we do,”” said Jeremiah Haas, Cordova Exelon Principle Aquatic Biologist. “First, we watch over the river and any effects the plant may bring to the fishery by what we call long-term monitoring. And second, we operate a hatchery that adds fish to the native populations.””
Long-term monitoring has four activities:
— “We electro-shock the same eight sites two times per month from June through September,”” Haas said, “keeping exact track of what we find each time and comparing that to what has been found previously to index findings.
–“In October and November, we haul-seine the same four locations four times with a huge net that is 1,000 feet long and 20 feet tall and has one and a half inch mesh. In one pull of the net, handled by six of us, we capture every fish over about eight inches in length from an area covering about three and a half acres and we keep exact data for indexing comparison.
— “In the spring, we tag about 3,000 fresh water drum (sheep head) and later try to re-capture as many as possible to monitor their continued health. We do this because drum seem to be the fish species most susceptible to harm from the plant. And, of course, we get calls from anglers who catch the tagged fish.
— “Year-round, we monitor what we call impingement by once-a-week collecting a 24-hour sample of everything that collects on the three-eighths inch mesh screen on the river water intake pipe. Over a year we will typically see over 60 aquatic species there.””
The fish hatching, rearing and stocking program involves two species: walleye and hybrid striped bass.
“In early spring we try to capture about 40 male and 40 female walleye from the river and hold them in tanks for observation,”” Haas said. “When the females are ready to spawn, we milk the fish and collect the eggs and then release the female back into the river. We do the same thing with the males and their sperm; then fertilize the eggs in hatching jars.
“We have about an 80 to 90 percent success rate of hatching, which is far better than in the wild. From six or seven million eggs, we get five or six million fry hatched. After four days in tanks, about three and a half million fry are released into the 63-acre former cooling canal where they grow to two-inch long fingerlings in about seven weeks. The remainder of the fry are utilized by other fisheries organizations such as the Illinois and Iowa DNRs.
“Five or six college-age summer helpers manually pull seine nets through the canal to capture the fingerlings. We try to mark about a third of the fish with a “brand”” made by touching the side of the fingerling onto a metal bar super-cooled by liquid nitrogen. This permanently identifies the fish as “ours”” and does no harm to it. And, with that, we have a statistical way of keeping track of “our”” walleye.
“And finally, we release the fingerlings into the Mississippi. We have an annual target of providing 125,000 into Pool 14 and 50,000 into Pool 13. This year we missed the target and stocked 143,000; last year we exceeded target with 217,000 and the year before we had 235,000.””
Has the walleye stocking operation had a noticeable effect on the walleye population in Pool 14? Absolutely, yes. Many studies by federal and state biologists show that at least a third of the walleye in Pool 14 came as a result of operations by Exelon in cooperation with Southern Illinois University at the Cordova facility.
“The other fish stocking operation involves hybrid striped bass,”” Haas added. “We purchase three-quarter inch fingerings from Arkansas, then keep and feed them in holding tanks until released into the Mississippi when they are six to seven inches long. Most of them stay in pools 14-17, but they”ve been caught as far way as Peoria and Des Moines. The last three years we”ve stocked from 10,000 to 12,000 per year.””
Haas is proud of the fish stocking program, pointing not only to the number of walleye found in Mississippi River Pools 12 –19 attributed to Exelon and SIU, but also to the size of some marked walleye — many exceeding 12 pounds. He currently has a friendly bet with the Iowa DNR biologists that a new state record “;eye (currently 14 pounds even) will soon come from Cordova released fish. Stay tuned…
Now, trivia question number one: how many nuclear plants in the US incorporate a fish stocking program in their activities? And number two: how many fish have been produced and stocked by the Cordova operation since inception? Maybe we should call it “the six million that got away.”
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