SPICER, Minn. — With its waters becoming clearer and warmer, Green Lake is seeing a decline in the number of walleyes it holds.
The Minnesota Department of Natural Resources is proposing to reduce the daily bag limit from six to three walleyes, with one over 20 inches allowed, to protect the walleye population going forward.
“I really don’t think it is going to get better, significantly better,” said Dave Coahran, fisheries supervisor with the Minnesota DNR in Spicer. “If we can maintain what we have, that would be a win in my opinion.”
Coahran spoke to about two dozen anglers who attended a public meeting Wednesday, Sept. 18, in Spicer to learn about the special regulation being proposed. The meeting is the start of a 10-day comment period. The DNR aims to implement the new regulation starting with next year’s fishing opener.
The area fisheries supervisor said his staff has seen a steady decline in walleye numbers in the gill nets they place in the lake. In the 1990s and into the 2000s, the fisheries staff usually pulled up 10 to 15 walleye per gill net. Today they are happy to see six.
The two big drivers in the decline are the trends toward clearer and warmer water. Water transparency was measured at 6 to 8 feet in the 1990s, when walleye numbers in the lake were at a peak. That’s also the optimal water transparency for walleyes, which rely on their ability to see in low-light conditions to find their prey.
Today, water clarity in the lake is more often in the 12- to 18-foot range.
The clearer the water, the greater the sunlight penetration, and the warmer the lake gets. The lake’s thermal temperature has now warmed above the threshold considered optimal for walleyes, according to Coahran.
Another big factor in the decline of the walleye population is the arrival of zebra mussels, first detected in the lake in 2014. The mussels filter the lake’s phytoplankton and make the waters more transparent.
By robbing the lake of phytoplankton, the zebra mussels have caused a major decline in the zooplankton on which the young walleye feed. Walleye rely on zooplankton as their food source for the first two to three months of life. Coahran said the loss of zooplankton very likely harms survival rates for new walleye.
Because of the presence of zebra mussels, Coahran said he doesn’t believe it is realistic to expect the current trend toward the clearer and warmer waters will change.
It's a trend being seen in many lakes around the state. "Green Lake is not alone," he said.
To maintain the walleye fishery as best as possible, the DNR has revised its stocking efforts. It is now aiming, with help from the Green Lake Property Owners Association, to stock up to 4,000 pounds of pond-raised walleye that are 10 inches or longer each year. The bigger fish have a much higher survival rate than stocked fry. They are past the life stage when they feed on zooplankton. They are also less susceptible to predators. Coahran believes the lake’s young walleye are increasingly vulnerable to predators due to the clearer waters and a reduction in perch.
Coahran said the DNR will also continue to stock walleye fry every other year. It is the most economical of the stocking options.
The proposed reduction in the bag limit has found support from many lake residents. Ann Latham, a longtime advocate for the lake’s walleye fishery, said she believes it’s the time to do it. It helps assure there remains a healthy walleye population that can withstand the changes taking place in the lake, she explained.
But there were also concerns raised at the meeting. Dale Ryks, of Willmar, has fished the lake for 45 years and pointed out that he has placed in the money in 28 of 30 tournaments on it. He said walleye fishing remains good and he doesn’t believe walleye numbers are down as much as the DNR calculates based on the gill net results. Ryks said the walleye have adapted to the changes by migrating more often to deeper waters and vegetated areas, and consequently are not showing up in the nets.
“The problem I see in Green Lake is bait,” Ryks said. He said he sees large schools of sunfish and smaller perch, and believes the walleye have all they can eat. “Why would you bite when you’re full?’’ he asked.
Ryks said he would prefer to see a statewide walleye limit of four per day and four in possession, the same as in South Dakota.
Duane Hanson, a lake resident who has fished its walleyes for 50 years, said he has seen a steady decline in the walleye catch. He told the audience in Spicer that he has also seen a corresponding decline in the number of anglers who pursue them.
Summer angling pressure is down on the lake, but winter pressure is up, according to Coahran. He said in the 1990s, creel surveys showed that 90 percent of the anglers on the lake targeted walleye. This year, 50 percent did so.
The creel survey this year found that roughly 59 percent of the anglers supported the proposed three-walleye limit; 10 percent were neutral; and 30 percent were opposed.
The DNR invites comments on the proposal. Send them to: Dave Coahran, DNR Area Fisheries, 164 County Road 8 N.E., Spicer, Minnesota 56288
Comments will also be accepted via email at firstname.lastname@example.org; or by telephone at 320-796-2161.
All comments must be received by 4:30 p.m. Sept. 30.
Public comments will also be accepted during an open house from 6 to 8 p.m. Wednesday, Sept. 25, at the DNR Central Office, located at 500 Lafayette Road in St. Paul.