New stocking strategy helping numbers on Lac qui Parle Lake in western Minn.
MILAN BEACH RESORT -- Before most anglers catch their first walleye of the season, Kyle Anderson and Doug Pierzina will have let something like 25,000 of them slip through their hands.
But not before they take the time to snip a piece of the ventral fin from each of them.
Anderson and Pierzina are fisheries workers with the Minnesota Department of Natural Resources in Ortonville. The two and their co-workers have spent lots of time this spring netting yearling walleye from fish ponds, and hauling their catch over to Lac qui Parle Lake.
They toss each fish into the lake only after they've clipped a fin. It slows the stocking process, but it can later provide the data needed to tell if a new approach to stocking the lake is working.
So far, the results are encouraging. Last fall's testing showed that 71 percent of the walleye of the year's class were the stocked, clipped fish, according to Norm Haukos, fisheries supervisor in Ortonville.
By fall, the clipped portion of fin on a fish has grown back, but the evidence of the earlier amputation is easy to see. That makes it possible to monitor the stocking program.
The new strategy involves stocking larger, yearling walleye in the spring rather than in the fall. The walleye are being introduced at a time when there are "optimal conditions'' for their survival in the wild, said Anderson as he snipped fins at the Milan Beach Resort on Monday of this week.
As the days lengthen and the waters warm in spring, the forage base that the hungry walleye need grows and grows.
The larger, yearling fish are less vulnerable to other predators and can eat a wider variety of forage than can the young and smaller frylings, which are mainly stocked into lakes.
In recent years, as many as 4,500 pounds worth of walleye were being stocked annually to help offset poor natural reproduction, according to Norm Haukos, fisheries supervisor for the Orontonville office.
They are seeing better results stocking 2,500 pounds of yearling walleye in the spring, which average roughly eight- to 10-fish per pound.
During the last six years more walleye have been stocked in the lake than probably in all of the preceding years.
That's because the lake has not seen a good natural reproduction since 2001, said Haukos.
A lake in this area needs to see a good natural reproduction at least once in every three years to maintain a strong population and meet angler expectations, noted Anderson. Stocking is needed to maintain a viable population in the lake, although it's no match for good natural reproduction, he said.
The lake is managed first for flood control, and the rapid rise and fall in water levels and lack of overall stability in the natural system can be detrimental to spawning, said Haukos. The walleyes spawn when waters are high, but a quick draw down can leave their eggs high and dry.
Also, the spring flows often carry lots of sediment and silt that smother the eggs.
Haukos said they also believe that the experimental slot limit regulation that had been in effect on the lake hurt walleye numbers. In place from 1996 through 2004, the slot had the effect of creating lots of hungry mouths under the slot limit size. They devoured the forage base, said Haukos.
The slot limit has been replaced with a four walleye limit, with one fish over 20-inches allowed. That, along with the aggressive stocking program, seems to be producing the desired results. Gill-net testing has shown improvement from a catch rate as poor as five walleye per net to 10 last year, said Haukos.
The goal with the new strategy is to see that gill-net catch improve to 20 fish per net.
One good year of natural reproduction could really boost the numbers, but until then Anderson and Pierzina and their co-workers intend to continue clipping fins.
They will return in the summer and again in the fall to assess how it's going.
Haukos believes anglers could get an idea of how it's going as early as this weekend. He's expecting a much improved opener on the lake this year, based on the increased population of walleye produced by last spring's stocking.
This year, lots of those walleye are now 15 to 16 inches in size -- exactly what many seek for the frying pan.