CASS LAKE, Minn. — The walleye and perch fisheries on Cass Lake continue to thrive and Department of Natural Resource officials are expecting another enjoyable year for anglers.
“Cass Lake still has strong walleye numbers and the resort owners have told us that the perch fishery exploded last fall,” said Tony Kennedy, Bemidji Area DNR Fisheries large lake specialist. “The perch are growing 2.5 to 3 inches per year and that just normally doesn’t happen. Some 5-year-old perch that we sampled were already 12 inches long and we have heard several reports of fishermen catching perch that were 13 inches. And catching big perch is a fun fishing experience.”
The walleyes in Cass Lake also have displayed rapid growth rates and about half of the 16.2 walleyes per net that were sampled in 2018 were between 14 and 18 inches. Many of those fish represent the strong 2013 year class and those walleyes, plus the survivors of more recent strong year classes, should ensure quality walleye fishing in Cass Lake for years to come.
“In addition to the 2013 fish, there is a fair number of 2-year-olds that are about 12 inches,” Kennedy said. “The 2018 year class that we sampled last fall also looks good so Cass Lake seems to be clicking right along. It is an amazing fishery that looks good for now, good for the near future and good for the (foreseeable) future.”
Zebra mussels also are established in Cass Lake and their arrival could be a component in the quality walleye and perch fishery exists now. An unintended food chain in Cass Lake sees the zebra mussels filtering zooplankton and depositing those nutrients as sediment onto the lake bottom. Another invasive species, the rusty crayfish, is the immediate beneficiary of that food source and the crayfish, in turn, become food for the perch and walleye.
“The rusty crayfish has been in Cass Lake since 1997, but in the last five years, that population has expanded lakewide,” Kennedy said. “I think, and I’m just speculating, the introduction of the zebra mussels could have triggered the explosion of the rusty crayfish. And, until the crayfish grow too large, they provide great forage for the perch and the walleye.
“The question is, will these growth rates continue or will the lake correct itself and return to normal? Right now, however, Cass Lake is the place to go for jumbo perch in our work area.”
The zebra mussels are very efficient at filtering the water and anglers have had to adjust their tactics and schedule to target the lake’s walleyes.
“There has been an increase in anglers fishing at night,” Kennedy said. “That trend even pre-dates the zebra mussel invasion. Cass Lake is a multi-purpose water, has a strong resort compliment and is filled with activity, especially during the day. In the evening is when families have the opportunity to go fishing, and the fishing is better in low-light periods and when there is a chop on the water. The walleyes are still using the shallow water during the day but they spook easily. By the time you see them, the walleyes have already seen you.”
In August and September, DNR officials will conduct a complete gill net assessment of the Cass Lake Chain of lakes which include Big Wolf, Andrusia, Pike Bay, Kitchi and Big and Little Rice lakes.
“The Cass Lake Chain is one population of walleyes because the fish move around all the time,” Kennedy said. “We do this assessment every 10 years and it gives us the opportunity to look at the walleyes in the entire chain.”
Other fish species
The muskie population on Cass Lake also is healthy and features small, medium and large fish.
“Cass Lake offers better muskie catch rates that many other lakes,” Kennedy said. “There also is a well-balanced size structure. There is a good chance to catch a muskie and it could be any size, including over 50 inches.”
Large northern pike also prowl Cass Lake’s waters as the population structure seems to be shifting away from numbers and toward better sizes.
Last year the state was divided into three zones in terms of pike regulations and Cass Lake is governed by the North-central Zone regulation which offers a daily limit of 10 northern pike. Of those 10, anglers can keep only 2 that are over 26 inches and all pike 22 to 26 inches must be released.
“I think the North-central regulation is good for Cass Lake. It was designed for lakes like Cass that have the capacity to grow larger pike,” Kennedy said. “We are seeing a decline in the total pike population and we are glad to see it come down. The lower density (of pike) will help grow larger pike.”
For more information on Cass Lake, contact the Bemidji Area DNR Fisheries office at 218-308-2339.