DNR collects walleye eggs for Mille Lacs fry stocking
Isle, Minn. — Even though DNR fisheries managers have repeatedly said that stocking walleyes into Lake Mille Lacs isn’t necessary, they collected 25 million eggs from the lake for a stocking research project that will see 5 to 10 million fry released back into the lake soon.
The DNR estimated it caught and released 300 female spawners for the project, and many of the fish that were on display Monday morning at the boat launch at Father Hennepin State Park, where the egg-taking operation took place, reflected the trophy fishery for which Mille Lacs is known, fish up around 30 inches long.
“Some real giants,” said Roger Hugill, the retired DNR Hinckley area fisheries manager, who was hired back on last year to become project leader of a reorganized Mille Lacs fisheries office.
The stocking research project comes at a time when the agency is under increased pressure over the management of the fishery, which has an abundance of smaller walleyes that were hatched in 2013, the only sizeable up-and-coming year-class of walleyes.
State managers, bound by a Supreme Court-mandated tribal co-management of the fishery, set the quota at 40,000 pounds (28,600 pounds of which is for state anglers, the rest for tribal anglers) for the second year, which led to a completely catch-and-release regulation for recreational anglers this year. The DNR also had included a live bait restriction, done at the behest of a Mille Lacs fishery advisory group that had pleaded with the DNR to do anything it could to prevent the walleye fishery from closing, but then went back on that rule after opposition raged.
In recent years, stakeholders and anglers have publicly asked the DNR to stock the beleaguered fishery, but managers have stressed that Mille Lacs’ walleye woes are a “recruitment” issue, which means plenty of wild walleyes have been hatched in recent years, but, for some reason, they aren’t surviving their first year, by and large.
So why, then, stock 10 million fry?
The reason is to collect information for a worst-case scenario if a time comes when there are not enough walleyes to spawn, DNR officials said.
“As of right now, we think there are plenty of wild fry being produced,” said Brad Parsons, the DNR’s St. Paul-based central region fisheries manager. “We can learn the hatching success of the eggs. We have done it on other lakes.”
To do that, the DNR will be chemically marking the fry with the common antibiotic tetracycline, then sampling young-of-the-year walleyes this fall, when the fish are about 6 inches long, which will give them a ratio of stocked to wild walleyes.
By cutting out the otoliths (ear bones) of a small sample of walleyes, they will be able to “estimate critical parameters of the wild fish, including natural hatch rate and numbers of naturally-reproduced fry.” The DNR has used this method on several other lakes such as Vermilion, Leech, Otter Tail, Winnibigoshish, Red, and Woman.
The fry collected were taken down to the DNR’s hatchery in St. Paul, where they will hatch after 10 to 17 days, depending on water temperature. The DNR is hoping they match the natural egg hatch on Mille Lacs.
That data would, if used as the basis for a stocking program, tell the DNR how many fish to stock.
“You can have too many fry out there competing with each other,” Parsons said. “More is not always better. That is a very hard concept for us to get across to people.”
Parsons said the egg-take was the first ever for Mille Lacs. In general, most of the state’s egg-takes are done on rivers, because it is generally easier to get at fish since they are concentrated. But in the case of Mille Lacs, long considered a world-class walleye fishery, the DNR said maintaining the genetic integrity of the lake’s walleyes was important.
“We had to take the eggs from here because the genetics are very unique,” Parsons said, noting that despite that, it would probably be hard to tell a Mille Lacs walleye from any other.
The DNR actually ended up with more eggs than it needed, and it remains to be seen where any surplus may end up being stocked, Parsons said. They wanted to make sure they had enough for the project, since the hatch rates can vary. They collected more than enough eggs to give them what they needed at a 50 percent hatch rate, though hatchery hatch rates can often be up near 80 percent.