By Louie Stout
Naturally-produced steelhead smoltAddition by subtraction may not make sense to some, but trout and salmon fish managers believe it does when stocking the St. Joseph River.
Beginning this year, Skamania will be stocked in fewer numbers, but biologists believe it will increase the fall returns because the fish will be stocked as a larger size and survive better.
Previously, Indiana stocked 130,000 7-inch Skamania. Beginning this year, that number will be reduced to about 75,000 8-inchers.
The strategy has worked with walleye on the St. Joe, where a stocking number reduction, coupled with planting larger fish sizes, has delivered a better fishery.
The salmonid plan calls for 30,000 coho and 20,000 steelhead to be stocked this fall, followed by another 60,000 coho and 80,000 steelhead next spring.
Historically, Bodine has stocked the majority of its steelhead in the spring.
We havent been happy with our fall coho returns and think this could provide us a better river fishery from August through early spring, said Lake Michigan biologist Brian Breidert.
So how does all of this produce better fishing?
The coho change is pretty simple to understand. For now, biologists will plant 90,000 coho as they have in the past. Breidert said holding onto the majority of coho for a spring stocking gives them a chance to grow larger and compete for food. In addition, by releasing them in the spring and not fall means they should run directly to the lake and not spend the winter in the river where they can be eaten by other predators or deal with the harsh river environment.
Studies show that smallmouth, walleye, catfish, pike and the few muskie in the river likely dine on young salmonids during cold weather months when the forage base is low.
That makes sense, but how does reducing Skamania stockings equate to more fish?
By adjusting our Skamania numbers in the hatchery, the fish we do stock in the spring will go in at a bigger size, said Breidert.
Studies also have proven that the fewer number of fish you hold in hatchery ponds, the bigger they grow.
So, even though the steelhead will be stocked at the same time and in fewer numbers, Breidert expects them to be about 1? inches longer.
Research indicates you can double the number of fish returning to the streams by simply increasing the relative size, said Breidert. We normally see about a 2- to 4-percent return (of the initial stocking number) to the river and think we can get 6 to 8 percent, or possibly better.
Breidert points to 2006-07 when Mixsawbah Hatchery was shut down and Bodine had to handle the bulk of the trout and salmon stocking. Because of the additional fish, the fish went in smaller and the returns werent great.
But when Mixsawbah was back online the next year, the size increased along with returns, he said.
Breiderts concern about fall-stocked coho being eaten by other gamefish is puzzling to the average angler. Fall-stocked coho go in at about 5? inches; theyll be about 2 inches longer when stocked in the spring.
Even so, a 5-inch coho seems like a pretty big bite for the majority of smallmouth and walleyes in the river.
Not so, says Breidert. The young salmonids are long and slender, much like suckers that get devoured in the river by gamefish.
Weve done studies in our tank and have seen 12-inch smallmouth eat 7-inch steelhead, he said. A 15-inch smallmouth or walleye will have no problem eating those young fish, and when you think of the number of big catfish hanging out below the spillways of the dams, you can see how predation could be a factor before the fish get to the lake.
The new stocking plan is considered a pilot program to be assessed in three years. Biologists wont know for sure until the fish return as adults from 2018 through 2020.
Details of the proposed changes are at www.in.gov/dnr/fishwild/3625.htm.