As a biologist neatly inserted tracking devices into the sides of sedated carp, one thing was clear: plans to clean up Lakes Winona, Agnes and Henry are underway.
There are other signs, too: on Lake Agnes, there's a new solar panel, a green utility box and a contraption around the inlet from Lake Winona, and another such device on Lake Winona near the Alexandria Police Department.
The contraptions are carp counters, installed by Wenck Associates, which is contracting with the Alexandria Lake Area Sanitary District to tackle pollution in the Winona-Agnes-Henry chain of lakes.
"We verified what we suspected, that there's a very dense population of carp here," said Joe Bischoff, water quality manager with Wenck.
Carp stir up phosphorus along lake bottoms that settled there before the city's sewer system followed today's stricter pollution controls. Officials want to remove the carp and are trying to track how plentiful they are and where they go.
So it was that on Thursday, Sept. 26, project biologist Aaron Claus and environmental scientist Nick Omodt went electrofishing on Lake Winona. They scooped up 10 carp and came ashore. They dunked the fish, one at a time, into a bath of clove oil, an essential oil that acts as a sedative. When the fish rolled over in the bath water, they picked them up, set them on an inflated bag on the tail gate of their work truck and went to work inserting radio telemetry transmitters.
Claus flicked off a few of the fish's golden scales before opening a slight slit in its side.
"My affectionate name for them is golden trout," Claus said with the slightest of smirks.
"Too bad they don't taste like trout," someone else commented.
Carp are tough, tough fish, the scientists say that can live up to 80 years or so. A carp's scales will grow back quickly. If it loses a fin, it'll grow back in about three months. Omodt saw one that had survived having half its face ripped away; its flesh had healed around a fish hook. They can survive in polluted water with low levels of oxygen; when winter kills off game fish, carp not just survive, they thrive. That's prime time for them to reproduce, because of the lack of predators for their young.
These fish are getting two trackers. This winter, when the ice freezes, Claus and Omodt will return with tools to locate the 10 fish with the telemetry transmitters. In the winter, carp group up, like deer, and knowing where they are will help figure out how best to remove them.
Claus learned surgery as a boy from his dad, a physician, performing small operations on horses and dogs when needed. He stitches up the fish's wound with dissoluble sutures, brings it back to the boat and sets it in another tank of water to ensure that it lives. When it is finally released back into Lake Winona, it's still sluggish. It bonks into the boat before making its way back into Winona's shallow waters.
These fish, plus nearly 500 more, have also been injected with half-inch-long transponders.
When the fish swim from Winona to Agnes, those transponders will send its identification number, date and time to the carp counter, called a passive integrated transponder antenna. The technology is also used in pet identification chips. The data will tell the scientists about where the carp are traveling.
The carp have been counted starting Sept. 10, but it's too early to draw any conclusions, the company said. The fish need to be tracked over a year or more before the company can figure out the best way to remove them.