Study Reveals Indiana St. Joe River Bass and Walleye Movements


River smallmouths are homebodies.

That is a bit contradictory, given the belief that smallmouths are nomadic. That may be the case in lakes, but not necessarily in the St. Joseph River.

At least that’s what Dar Deegan, aquatic biologist for Elkhart and St. Joseph counties, has been discovering in his analysis of an ongoing tagging study his office has conducted since 1998.

Deegan spends his time monitoring water quality and the health of fish in St. Joe and its tributaries. While conducting on-the-water research, he collects some information on gamefish with electro-shocking and records their growth data and their overall health condition.

River researchers now have placed tiny tags in the backs of smallmouths, walleyes and a few largemouths that measure 12 inches or bigger before they are released. The tags have small print that alerts anglers to contact Deegan and his team when they catch the tagged fish. Each fish carries an identification number.

River researchers place tiny white tags in the backs of adult gamefish as part of an ongoing study. Anglers are encouraged to report tagged fish they catch and their identification numbers to aquatic biologist Dar Deegan whose number is printed on the tags.

Over the years, Deegan has tagged 4,000 smallmouths, 900 walleyes and 100 largemouths.

“When an angler calls us with the information it helps us learn more about the habits of that fish since it was tagged,” Deegan said. “We learn about its movement, how much it has grown and other data that helps us understand river conditions.”

The anglers benefit as well. Deegan will tell the anglers where in the river a fish was tagged and how old it is and any other data he’s collected.

“The angler doesn’t have to kill the fish or remove the tag,” Deegan explains. “If he wants to release it, he can clean algae off the tag, get a clear picture of the identification number with his cellphone, measure the fish and call us with the info.”

The reports he’s received so far has led him to believe smallmouths tend to stay in the same areas throughout the fishing season. However, it also supports the fact that gamefish do migrate during different seasons.

For example, one smallmouth that biologists captured a few years ago under a fallen tree was tagged and released about one-quarter mile downstream. Several weeks later his crew shocked up the same smallmouth from under the same tree. Deegan wasn’t surprised at this since other river-tagging studies in the Midwest have shown that smallmouth bass will spend their lives in the same area they were born in.

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Interestingly, tributary smallmouths (bass in Elkhart River, Christina and Baugo creeks) will spend their summers in the creeks, but do migrate down to the deeper main river section when water temperatures drop in the fall. They’ll spend the winter in the main river then migrate back to the creeks in the spring.

“We’ve had anglers catch fish in the winter in the St. Joe and we will find that same fish up in a creek that next summer,” Deegan said.

Other results show walleyes run up the streams or the areas of the upper river in the spring, which is obvious by the number of walleyes caught below dams earlier in the year.

“After the spawn they migrate downriver to get in the slower current and stay there during summer and winter.”

The study also confirmed that some walleyes—about 10 percent according to results—get swept

downriver. Fish that he’s tagged in Elkhart and Mishawaka have been caught in the subsequent river impoundment downstream.

Deegan said largemouths don’t show the same fidelity to a river as he’s seen with smallmouths. In fact, he’s recorded largemouths that swim out of the river up to Trout Creek and get caught by an angler in Michigan’s Long Lake, a 15-mile journey.

“I suspect some end up going back to the river but I haven’t been able to document that,” Deegan added.

Deegan plans to tag approximately 300 more fish this summer and hopes that anglers will spread the word and report their catches of tagged fish.

“Anglers have told us they have caught our tagged fish in tournaments and released them because they didn’t want to hurt the fish. We understand and appreciate that, nor do we want them to remove the tag. If they can handle the fish carefully and get us the data off that tag it helps immensely. The more reports we get, the more we can learn about our gamefish and share that knowledge with anglers.”