DNR explains status of Cass Lake Chain, Pike Bay
When area DNR officials invite the public to an informational meeting, predicting the potential crowd is impossible.
Last week at the Pike Bay Town Hall, Bemidji DNR Fisheries personnel hosted a public meeting designed to discuss the walleyes on the Cass Lake Chain and more than 30 people attended.
"I was very pleased with the turnout," said Bemidji Area DNR Fisheries Supervisor Gary Barnard. "Gathering this information required a great deal of work and when you go through a project like this you want to know that people are interested.
"The turnout at Pike Bay proved to us that the people are interested in the Cass Lake Chain."
What the people discovered through the DNR presentation is that the walleyes in the Cass Lake Chain are doing well and that the prospects of that trend continuing are strong.
"The walleye population in the Cass Lake Chain is in good shape and the spawning stock is also good, but not excessive," Barnard told the crowd."
The DNR officials also had the data to support their statements. Through a variety of sampling methods, including live capture and fin clipping during the spawning run, fall gill netting, creel surveys, shoreline seining and trawling, fall adult recapture and electrofishing, the officials collected data on adult spawners and their progeny.
The study lakes in the Cass Lake Chain included Cass, Andrusia, Big Wolf, Kitchi, Big Rice and Little Rice.
The data indicates that the chain averages 1.5 pounds of spawning female walleyes per littoral acre and, according to Bemidji Area DNR large lake specialist Tony Kennedy, the figure is a little above average for lakes of this type.
In Cass Lake that data translates to about 39,351 spawning females while Andrusia's estimated population is 3,272 and Big Wolf's is 2,540.
The spawning practices of the chain's walleyes also were studied and officials discovered that 89 percent of the spawning fish in the chain call Cass Lake home.
In the 2010 assessment 401 walleye fry were marked with tetracycline and during the recapture effort in the fall 252 of those fry were found.
Those numbers indicate that of the 2.8 million fry in the system, 1.76 million were stocked fish and 1.04 million were naturally hatched.
"The study shows that the current fry stocking program for the Cass Lake Chain appears to be well directed," Barnard said.
"Cass Lake has good walleye recruitment on a regular basis and is able to replace the fish through that recruitment," Barnard continued.
"The total fry density (wild and stocked fry) is not excessive on a system-wide basis. We also discovered that a large number of the wild fry are coming out of the Mississippi River system. And that means that protecting the river spawning habitat is very important and that the water flow during the spawning period has to be controlled."
DNR officials will continue to monitor the walleye population on Cass Lake and its adjoining waters.
Pike Bay lies just south of Cass Lake and the two lakes are connected by a slow-moving waterway.
Despite that connection, however, there is little interchange among adult walleyes and the two lakes act as separate systems.
"Historically, Pike Bay is low in walleye abundance but it is known for large fish," Barnard said. "Pike Bay has a physical connection to Cass Lake but has an independent fishery and there is a long history of stocking efforts to enhance the walleye abundance."
For the most part, however, those efforts have not been successful.
Fingerling walleyes have been the preferred stocking tool for the majority of Pike Bay's history and in 2004 DNR officials doubled the traditional number of fingerlings to 2,238 pounds.
"The goal was to improve walleye abundance in Pike Bay by 25 percent and to do that we needed to double the number of fingerlings," Barnard said.
After five years of double stocking, the DNR officials were eager to make their population assessment following the 2009 surveys.
They assumed that the efforts would pay big dividends.
"We had five years of doubling the stocking but when we did the 2009 assessment we found no change in the gill net catch," Barnard said.
"We repeated the survey later that year just to double-check but we had the same numbers. And that was very disappointing."
Historically it was thought that fingerlings would enhance some lakes much quicker and more efficiently than fry. Recent surveys within the Minnesota DNR stocking programs, however, have indicated that fry stocking typically is more productive than fingerling stocking in terms of improving a fishery.
Among the area lakes where that has proven to be the case is Big Lake as the walleye population has thrived since fry replaced fingerlings in the stocking rotation.
"Pike Bay always has appeared to be the type of lake that should be good for walleyes and now it seems to be a lake that could be helped by stocking fry instead of fingerlings," Barnard said.
The current plan is to stock two million fry each year for five consecutive years.
"That's probably more than we need but we want to make sure that the stocking will take," Barnard said. "We will electrofish each fall (to determine fry survival) and in five years we'll be set up for another gill net assessment.
"That will tell us where we stand," he added. "We're excited about this plan. We think it has a good chance of working.
"Hopefully it does and Pike Bay can become as good a walleye lake as we think it can."