Fish barriers keeping carp out of Lake Ocheda
WORTHINGTON -- Earlier this summer, Okabena-Ocheda Watershed District Administrator Dan Livdahl witnessed literally thousands of carp in the channel between Peterson Slough and the western basin of Lake Ocheda.
The rough fish were gathered there because 10, five-foot wide steel gates were put in place along the dam in mid-April to prevent them from reaching Lake Ocheda and adding to the already high population of carp there. Livdahl said the prairie lake, at nearly 1,700 acres in size, has an estimated 600 or more pounds of carp per acre. The fish repopulate at incredibly high rates -- some carp-related websites claiming it's as high as 1 million eggs released per adult female per season.
The carp, many of which do their spawning in the slough and adjacent Ocheyedan River, swim upstream and jump over the dam to reach Lake Ocheda.
"The gates keep the carp from jumping ... into the lake," Livdahl said. "It was a good year to do experimenting because we had some high water this spring."
The effort to keep any additional carp out of Lake Ocheda is just one of several steps being attempted to improve water quality in the lake. Another step is the shoreline stabilization project taking place on the Langseth shoreline along the east basin. A story on that project was in Friday's Daily Globe.
Despite both of those projects, Livdahl said a lake draw-down, whether it's naturally occurring or planned, is still needed to eradicate the high levels of rough fish. Once that is done, vegetation can be re-established to create an environment in which predator fish such as northern, perch and other panfish can thrive. Carp feed on the bottom of the lake and stir up the sediment, which blocks light from penetrating through the water to promote vegetative growth.
"The water clarity in the lake is poor because of the carp, but also because of wind action in the lake," Livdahl said. "If we get a natural draw-down or one we purposely do and get a freeze-out, we would probably see clearer water the following spring."
A draw-down would require approval from at least 75 percent of the people who own land around the three basins of Lake Ocheda. That process was discussed at landowner meetings in 2010 and 2011, but was halted after a commercial fisherman said he could fix the problem by seining the lake, Livdahl said. The seining has not been done, and he doesn't know if it will be.
"I think we had people convinced that a draw-down wouldn't be a bad plan," he said. "They thought (the seining) was a magic bullet."
Livdahl is hopeful the landowner group will begin meeting again to discuss a draw-down.
Meanwhile, the gates will remain in place on the dam, which is located on the south end of the west basin. A permit was requested from the Minnesota Department of Natural Resources to install the system after a prototype gate was tested last summer on the dam.
Livdahl said the gates, which can be opened manually if there is debris build-up, seem to be working well. They were constructed by Marv Rall of Worthington.
As for preventing carp from reaching the lake, Livdahl said the gates have been effective, but not 100 percent so.
"The barrier (system) isn't perfect," he said. "I observed two fish jumping right over the whole dam. They had to be able to jump eight feet in the air and 25 to 30 feet over the dam."
The jumping fish were small and golden in color, but Livdahl said they were likely carp.
Larger carp were seen jumping into the gates and bouncing back into the channel.
"We kept a lot of fish out of the lake," Livdahl said. "Whether that's sufficient to the lake, it probably isn't. Where it is most useful is if we have a fish kill in the lake. That would help manage populations more."
Daily Globe Reporter Julie Buntjer may be reached at 376-7330.