The local spawn harvest perseveres
Call them "Aquatic Dr. Spocks."
Call them "Aquatic Dr. Spocks."
Every year a round-the-clock fish breeding operation takes place in Park Rapids and other locations throughout Minnesota, to re-stock area lakes and boost Mother Nature's production of small fry.
A spring of wacky weather, fluctuating water temperatures and an abnormally warm March have made the spring egg harvest unpredictable, to say the least.
Fish won't lay eggs in cold water.
"This usually takes two days," said DNR Fisheries supervisor Doug Kingsley, who oversaw what turned out to be a weeklong harvest of sucker eggs in the channel between Lake Emma and Big Sand.
Some of the usual lakes yielded eggs during the spring spawn, some not.
The DNR measures success by the quart. For the sucker harvest, the goal was 120 quarts of an egg-sperm match. On a normal spring day when water temperatures reached 60 degrees, the job could be accomplished in about two days.
"It just dribbled when the weather cooled off," Kingsley said. Water temps hovered just above 50 degrees most days.
The DNR generally harvests walleye eggs from Woman lake, the suckers from Emma/Big Sand and muskies from Lakes Plantagenet and Elk, where the "brood stock" resides. Those are the pure strains of fish.
The suckers will be used for forage for muskies and to restock some lakes.
That's why this spring the timing is so critical.
Both are spawning at the same time. Ideally the DNR would like the suckers' growth cycle to lag behind the muskies. But that's why the Park Rapids hatchery has huge refrigerated containers.
"We can store them (the eggs) for up to a month," said Scott Muhm, the hatcheries supervisor. "We refrigerate them at 41 degrees until we need them. Last year we held them a month to slow them down."
On the lake
Dewey Goedon's day begins at 4 a.m. He dresses in thermal underwear, puts his waders on and heads to Big Sand Lake, where he'll start herding fish upstream into the channel to Emma by 5.
The nets and makeshift dock have already been set up. The channel has a good clean bottom and moving water. That's important so the eggs can stay aerated.
Once in the nets, the milking process starts.
Eggs and sperm are squeezed from the fish and mixed together. There's no precise recipe, Kingsley said, but having a two-to-one ratio of sperm to eggs "Improves the chances of good fertilization."
DNR employees use turkey feathers to stir the mix, picking out defective eggs, blood clots and debris. Back at the hatchery, a large jar of fresh feathers sits ready.
The egg mixing is a time-sensitive operation. The eggs are viable for about two minutes; the sperm, called milt, for 30 seconds.
Kingsley, Mike Kelly and Calub Shavlik all stir, squeeze and toss the fish that have been milked. Don Pearson wields the landing nets, constantly netting fish from the river nets and dumping them into metal pails. They work in a synchronicity that is obvious they've been doing for years.
Kingsley said the DNR is trying to replicate nature. Eggs laid along a stream bed will be aerated and spread by currents naturally.
Back at the dock, Dewey, in his waders, takes buckets of the mix and adds Bentonite, a clay stabilizer that strengthens the fragile eggs and assures they won't clump together.
Once the clay particles begin to set up, the eggs will swell two to three times their size by absorbing water. The clay forms a hard shell around the eggs while they sit in the slurry mix in a cradle for two to three hours.
Otherwise they're too unstable to transport back to the hatchery.
This process gets repeated in the afternoon. DNR employees take turns staffing a night shift, mainly to ensure beavers or muskrats don't infiltrate the nets, or worse, chew them up and free the fish.
Back at the hatchery
Muhm is surrounded by clear cylindrical tanks of gurgling water full of fish eggs. On a normal spring, all the tanks at the hatchery in Park Rapids would be full. Not this year.
Because of the flukiness of the lake temperatures, other hatcheries in the DNR system are pressed into duty with eggs that came from other areas. With the sucker eggs just harvested locally, 20 quarts will be shipped to a hatchery in New London.
Columns of walleye, muskie and sucker eggs line the hatchery. Each tube is marked with the type of egg and the day it was harvested.
Each quart has from 45,000 to 60,000 sucker eggs or 120,000 walleye eggs. It's an imprecise science. No one counts heads.
A system of water piped from the Fish Hook River circulates through the hatchery and oxygenates the eggs and water. Each tank is monitored for temperature and fungus during the incubation process. Muhm said the muskie eggs require the most scrutiny.
Then the waiting game begins. The muskies hatch in less than two weeks. Walleyes take 20-21, Kingsley said.
The eggs float to the top of the cylindrical tanks in their egg sacks, which will support them up to four days. Eventually they worktheir way into a trough and a large tank.
When they've turned to "swim-up fry" they eat zooplankton. In this stage they live in a series of nursery ponds. Some one-inch suckers will be used to feed the muskies.
Eventually the pond is drained down and the two-inch transplants will go to another pond with fathead minnows.
In some cases they can go from the fry tank to area lakes or natural rearing ponds.
"Some lakes respond well to fry stocking," Kingsley said. "It's the cheapest way. You get a lotta fish, lotta numbers."
Other lakes require fingerlings.
Some fish are kept in ponds through the summer and released in fall, when they're nearly a foot long.
The DNR does breed a specialty tiger muskie, raised from a male northern pike's sperm and a female muskie's egg. Those are generally shipped to the southern part of the state for lakes there.
To perpetuate the cycle of life - and angling - the unlucky minnows get used as bait.