By Louie Stout
As waters slowly recede from Michiana’s 500-year flood, the question remains among anglers: How were river fisheries affected?
We posed that question to area fish managers and none expressed any major concerns - yet.
Biologists say the fact that area rivers and streams pushed out of their banks in February is less threatening than if it occurred a few months later.
“The fact that the water is still cold and that most of the fish have been in their deeper holes is a good thing,” said DNR St. Joseph River biologist Larry Koza. “If it happened a couple of months later, I might be concerned about how it impacted the spawn or the young fish produced during the spawn.”
Northern pike could actually benefit from the higher water because pike like to spawn in flooded backwaters. Those fish should be spawning in the next week or so.
Indiana fisheries biologist Tom Bacula said we could see a high number of young pike (especially on the Kankakee River) produced this year - assuming the young fish hatched in flooded areas can make it back to the main river. Of course, it will be a few years before they reach a legal size.
“Pike lay adhesive eggs that stick to vegetation, buck brush and willows, so they would have plenty of spawning habitat in the flooded areas,” Bacula said.
Dar Deegan, Elkhart/South Bend St. Joseph River biologist, acknowledged that recent floods caused tremendous hardships on the communities affected, but points out that overall health of the river could benefit.
“Floods of this size create a big flush of sediment, cleaning off some of the gravel bars and creating a little more spawning habitat,” he explained. “It can actually be an overall benefit to fish habitat.”
As a result, he added, some of those gravel bars anglers fished last year may be altered or even shifted. You may also see more log jams along the banks.
Aquatic vegetation could be impacted, too. Places where weeds grew on mucky river bottoms may change. You may see less weed growth initially, but if we have a warm spring then we’ll probably see an explosion in weed growth, Deegan noted.
“All in all I think the fish community will be fine,” he said.
Of course, there are some concerns, such as the young walleye that were stocked last fall above Twin Branch dam. Historically – even under normal conditions – some of those stocked fish get swept through open flood gates, over spillways and into lower pools. Biologist say it’s possible that some of the young walleye planted in 2017 will wind up farther down river. The DNR will survey the river later this year to check survival above the Twin Branch Dam.
Deegan said that another flood this spring could be more troublesome for the young smallmouth bass population. Deegan compares his annual fish population surveys to historical hydrograph charts.
“I’ve seen a direct correlation between historical floods and slower growth of smallmouth bass,” he explained. “The adult fish do fine, but the little guys get stressed from being washed around the river.”
Furthermore, additional flooding during the spawning season can affect future smallmouth bass year classes.
“In years when we’ve had a flood during the spawn, it wiped out most of the smallmouth nests,” Deegan said.
Those steelhead trout that spend the winter in the St. Joseph River should be fine as well. Although present river conditions are unfishable, the strong downstream flow and warmer water temperatures have lured even more trout into the upper reaches and above the South Bend dam.
Although the official videotape count at the South Bend ladder only shows 48 steelhead passing the ladder since Jan. 1, Bodine Fish Hatchery crews reported seeing fish moving through during the high water period while they were there cleaning out debris.
Hatchery Manager Dave Meuninck says the underwater videotapes from February haven’t been read, but cautioned that the tapes may be difficult to read because of the murky water conditions.
“But we do know fish are moving up river,” he said.
As of mid-week, Indiana has tape recorded 6,187 steelhead moving above the South Bend dam during the past six months. Those fish will be spawning in the coming weeks before returning to Lake Michigan.