How Do Gamefish Respond to Floods?

Troubled waters: Flooding can bring complex issues for fish populations.

How Do Gamefish Respond to Floods?

Flooding events are part of the normal rainfall pattern throughout the Southeast, and they certainly affect wildlife populations. (Shutterstock image)

In January 2019, Mississippi had a flood event that affected much of the state along the Mississippi River. The Mississippi Department of Wildlife, Fisheries and Parks closed hunting seasons on a number of WMAs and set out supplemental feeding stations for wildlife affected by the rising water.

Such flooding events are part of the normal rainfall pattern throughout the Southeast, and they certainly affect wildlife populations. Under the surface, they affect gamefish populations, too, but in much different ways.

Matt Marshall is a fisheries biologist with the Alabama Department of Conservation and Natural Resources. He says the short answer to how flooding affects gamefish is, "It depends."

"It's a complex issue with both positives and negatives," he says. "Fish are adapted to flood responses; it's a natural process. It depends on the time of year when flooding occurs. For example, wetter winters produce better spawning and recruitment of crappie."


Other factors that affect the degree of impact include the species of fish involved, the length of the flooding event and the type of aquatic habitat.


Since Alabama's most important gamefish is the largemouth bass, the influence of floods on bass is an important issue for anglers. Marshall says time of year determines whether a flood is beneficial or deleterious to bass.

"If you have a flood event during the spawn, you can have a decrease in recruitment," he says. "The bass can build their nests at the normal water level, and then if it goes up six or seven feet, and you have turbidity issues, you could have fewer eggs hatch. The bass could compensate for that by increased survival of fry later in the spring and summer, so you might not really see the effects. Or you might see it several years down the road, with a slightly reduced catch rate of bass."

At other times of the year, flooding may benefit bass.

"In some riparian areas, you're adding nutrients back into the water, and you have increased forage," Marshall says. "There may be more invertebrates and more forage fish that move into bass cover."


In Florida, fisheries biologist Ryan Hamm agrees that it’s a complex topic.

"The effect on crappie depends on the timing of flooding during the year," he says. "It also depends on the conditions before the flooding. We've seen crappie in drought-stricken lakes during the fall, winter and spring months; then when we have a high-water event, we've seen crappie gravid and full of eggs in June."

The supposition biologists make, he says, is that the fish are taking advantage of good conditions for spawning because conditions were so bad when they normally would spawn.


"One thing that's different in Florida is that we have broad, shallow lakes, where a lot of other reservoirs in the Southeast have a lot deeper areas," Hamm says. "In many of these lakes—such as the Harris Chain of lakes, which is a popular crappie fishery—even when we have hurricanes, because of the water control structures there, we don’t see a six- or seven-foot increase in water levels. So we don’t often have those impacts or conditions."

In Lake Okeechobee, Hamm says, there are large expanses of marshes.

"There, if you have extended periods of high water that impact emergent vegetation, that will impact black crappie populations," he says.

If an extended period of low water allows emergent vegetation to grow up and then the water level rises and cover it, he says, it will create very productive conditions for black crappie.

"That's not exactly a flood event, but it is a change in water level," Hamm says.

Floods and Fish
A Florida Fish and Wildlife Conservation Commission biologist releases fingerling bass into state waters. Flooding events help provide additional food sources for younger fish, which generally are not negatively affected by floods. (Photo courtesy of Florida FWC)

OPENING THE FLOODGATES

Dennis Riecke, a fisheries biologist with the Mississippi Department of Wildlife, Fisheries and Parks, says fish move and utilize floodwaters to go wherever they want to go.

"Flooding will allow them to access bodies of water that are close to them and not normally connected, but with the floodwater they are connected," he says. "It certainly will allow them to use floodwater (areas) that previously were terrestrial."

High water also may allow fish species to move into and colonize bodies of water they have not had access to in the past. For the fish, this means access to more resources and more food items than they usually have. Riecke spoke particularly of a food study done on catfish after a flood.

"The biologists found mice in the stomachs of catfish," he says. "Floodwaters will wash all kinds of organisms in. Animals that haven't had time to escape will be washed into the water, and some of them will be preyed upon."

Floodwaters also wash all kinds of organic matter in the form of leaves, sticks, dead grass and other plant matter into bodies of water, which can be problematic.

"All of that starts to decompose," Riecke says. "That decomposition process consumes oxygen, and if there's a lot of organic matter that is being decomposed, there may not be enough oxygen left for the fish. You could have a fish kill, which we often see that after hurricanes. It's the result of natural processes, not because of contaminants or toxins."

If the high water occurs during a fish's spawning season, Riecke says, those fish may spread out through a larger area than they usually do to spawn.

"They may now have a lot more suitable habitat," he says. "Some fish that lay their eggs on vegetation need that spring rise to access spawning grounds on the floodplain."

The bottom line here is that high-water events are not as hard on any fish species as they are on wildlife. If anything, floods enable fish species to proliferate, as high water also can allow populations—both and non-native—to expand and enter new bodies of water. If the fish species moving into new water is an exotic, however, that can present a whole new set of problems for fisheries biologists to manage.

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Recommended Articles

See More Recommendations

Popular Videos

MLF Pro Tips: How to Fish a New Lake

MLF Pro Tips: How to Fish a New Lake

Major League Fishing pros Alton Jones, Jeff Sprague, Anthony Gagliardi and James Watson share their thoughts on how to approach fishing a new lake for bass.

Get on Board: Species for Beginner Anglers

Get on Board: Species for Beginner Anglers

With so many people turning to fishing as a way to escape the stress and challenges that have arisen in recent months, we've teamed up with the Recreational Boating and Fishing Foundation and the National Marine Manufacturers Association to explore some of the freshwater fish species you can target if you're just getting on board with fishing. #TheWaterIsOpen #GetOnBoard

Daiwa J-Fluoro Samurai Fluorocarbon Fishing Line

Daiwa J-Fluoro Samurai Fluorocarbon Fishing Line

Pro angler Cody Meyer calls Daiwa's J-Fluoro Samurai the best fluorocarbon he's ever fished. Meyer spoke with In-Fisherman associate publisher Todd Ceisner as part of the 2020 ICAST New Fishing Gear Guide.

SPRO Madeye Diver 85 & Minnow 120

SPRO Madeye Diver 85 & Minnow 120

The Madeye Diver 85 & 120 feature sound chambers that imitate various batfish.

See More Popular Videos

Trending Articles

Starting opening day, there's a small window to tag out before pressure impacts buck movement. Make the most of it. Whitetail

Quick-Strike Tips for Early Archery Deer Success

Tony Peterson - August 18, 2020

Starting opening day, there's a small window to tag out before pressure impacts buck movement....

Who needs live bait when the big 'gills are so eager to strike these lures? Other Freshwater

5 Great Lures For Bluegills

Stephen D. Carpenteri - March 10, 2011

Who needs live bait when the big 'gills are so eager to strike these lures?

Quick look at common, easy-to-catch fish species (video). Other Freshwater

Get On Board: Species 101 for Beginning Anglers

Game & Fish Staff

Quick look at common, easy-to-catch fish species (video).

If you haven't looked at the smaller urban lakes in your area, you are missing out on some great bass pond fishing. Bass

Bass Pond Fishing: Catch Lunkers at Small Lakes Near You

Dan Anderson

If you haven't looked at the smaller urban lakes in your area, you are missing out on some...

See More Trending Articles

More Conservation & Politics

The move is described as the largest expansion of hunt-fish opportunities in U.S. Fish and Wildlife Service history. Conservation & Politics

Trump Admin Opens 2.3 Million New Acres to Hunting & Fishing

Lynn Burkhead - August 19, 2020

The move is described as the largest expansion of hunt-fish opportunities in U.S. Fish and...

Op/Ed from the National Shooting Sports Foundation. Conservation & Politics

NSSF: Anti-Gun Police Chief Puts Out Hiring Call

Larry Keane - August 26, 2020

Op/Ed from the National Shooting Sports Foundation.

Op/Ed from the National Shooting Sports Foundation. Conservation & Politics

NSSF: August Background Checks Highest on Record

National Shooting Sports Foundation - September 03, 2020

Op/Ed from the National Shooting Sports Foundation.

Perspective from the National Shooting Sports Foundation. Conservation & Politics

NSSF: #GUNVOTE Critical for All Voters Ahead of Election

Larry Keane - August 21, 2020

Perspective from the National Shooting Sports Foundation.

See More Conservation & Politics

GET THE MAGAZINE Subscribe & Save

Digital Now Included!

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW THIS MONTH'S ISSUE

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Get Digital Access.

All Game & Fish subscribers now have digital access to their magazine content. This means you have the option to read your magazine on most popular phones and tablets.

To get started, click the link below to visit mymagnow.com and learn how to access your digital magazine.

Get Digital Access

Not a Subscriber?
Subscribe Now