WORTHINGTON, Minn. — A gathering of onlookers surrounded a rectangular hole in the ice recently just west of Chautauqua Park as a commercial fisherman and his crew harvested carp, buffalo fish and sheephead from Worthington’s Lake Okabena.
By the time it was completed, roughly 4,000 pounds of buffalo fish, 600 pounds of carp and a couple buckets of freshwater drum (sheepshead) were removed from the lake. Only one of the nearly 80 carp captured in Thursday’s event was previously tagged.
The haul was considerably less than what Okabena-Ocheda Watershed District Administrator Dan Livdahl and commercial fisherman Scott Deslauriers had hoped for.
“When you go fishing, there are no guarantees you’ll catch fish,” Livdahl said. “I was hoping for 20,000 pounds of fish so we could get a good estimate of the remaining population (of carp) in the lake.”
Lake Okabena is on the state’s impaired water list, and a high population of common carp are partly to blame. The invasive species roots in the lake bottom, stirring up sediment and destroying aquatic vegetation. A 2018 estimate pointed to an excess of 174,000 pounds of carp in the lake.
“We need to know the population to set some goals and get down to that 79 pounds per acre (limit),” Livdahl said. “If you have hundreds of thousands of pounds (of carp) in the lake, catching 500 pounds at a time isn’t going to get you there.”
The last seining efforts on Lake Okabena date back to 2006, when the Minnesota Department of Natural Resources harvested 7,430 pounds of carp from the lake, along with 9,306 pounds of buffalo fish — a species that looks similar to carp, but is native to Minnesota and doesn’t root up vegetation.
Skepticism about the lake’s carp population led to efforts in recent years to adequately estimate their numbers. Wenck, a Twin Cities-based engineering firm that specializes in hydrology, flooding and water quality, was hired eight years ago to assist the watershed district. Biologists did everything from electrofishing to surgically implanting carp with radio transmitters (they implanted 15 carp in the spring of 2019, and another 20 in the fall of 2020), and inserted 178 carp with Passive Integrated Transponder (PIT) tags in the fall of 2019.
It was the carp fitted with radio transmitters that helped guide the commercial fisherman to where he dropped a 2,200-foot-long net through the ice. He also had his own sonar equipment that showed a large population of fish in the area he planned to seine.
In the end, though, higher dissolved oxygen levels in the lake meant livelier carp under the ice. Many swam to freedom beyond the net as it was pulled toward shore.
“We located a fairly large school of fish,” Deslauriers said. “About 300 yards out from shoreline, we laid the net out parallel to the shore and went straight in.”
The process took about two hours, ending with the excess netting pulled up through the ice near Chautauqua Park and hundreds of fish captured within the netted area. Numerous game fish — including walleye, crappie, bluegill and catfish — were removed from the nets and immediately returned to the lake. The buffalo fish were sorted out and kept in a holding cage dropped into the lake, while the carp were temporarily kept in plastic bins.
Once the work was completed, the carp and buffalo were stored together before Deslauriers returned to load them up. They will be trucked to fish markets in New York. Meanwhile, the sheepshead were disposed of.
Deslauriers said the whole process went well, but he wasn’t pleased with the lower number of fish.
With the activity registering on his sonar, though, he’s already planning a return trip to Lake Okabena for open water seining this fall. At that time, he said he also plans to do some seining at Lake Bella.
“I built a second net, so now I’ll have almost a mile of net,” Deslauriers said. “If we can find those (carp) again, we can go from shoreline to shoreline and then we’ll have them in our net before we try to bring the two ends together.
“It could be a lot more effective than in the wintertime,” he added.
Deslauriers, who makes the most money on buffalo fish, said he figured most of what they’d pull from Lake Okabena would be buffalo because of their location along the shoreline. From what was captured, he said the lake seems to have a healthy population of buffalo fish, with a wide variety of sizes captured. The largest, he estimated, topped 40 pounds.
“We didn’t get a lot of little carp,” Deslauriers said, a possible indication that carp reproduction in the lake is hampered by other efforts, such as stocking of predator species that feed on carp eggs.
Still, the carp that were captured were large.
“Of the fish they measured, lengths and weights were considerably bigger than the average fish they estimated in the lake,” Livdahl said. “He thinks the pounds-per-acre estimate will go up.”