Frontal Assault- Flats Fishing After a Cold Front

A Special Report by Capt. John Kumiski

The wind blows from the south under a gray sky. A squall line approaches from the north. That south wind dies. It’s eerily calm.

Suddenly a frigid blast comes from the north. Rain lashes, whitecaps crash, the temperature drops 20 degrees in seconds.

A common winter phenomenon, a cold front has just passed through. How does the passing of a cold front affect the flats fisherman?

Unlike you, fish are cold blooded. A fish’s body temperature hovers within a degree or two of their surroundings. Redfish prefer 70 degree water. Spotted seatrout like it between 70 and 75 degrees.

As temperatures get below that their metabolic processes slow. They need less food. Get near the extremes of their tolerance and they become lethargic. Another degree or two colder and they die. We saw this demonstrated three winters ago during that extended cold snap. Dead fish were everyplace.

During the winter months, water temperatures in our local lagoons rarely get as warm as the fish prefer. Our finned friends seek water temperatures as close to their preferred range as they can find. Since shallow water warms (and cools) more quickly than does deep water, when conditions are right the shallows will be full of fish.

Right after a cold front passes the conditions are not right.

The passage of the front causes the air temperature to drop, which in turn lowers the water temperature. This drop in water temperature is exacerbated by a strong northwest wind, often at 20 to 25 miles per hour with higher gusts. An interested observer can stand on the bank at the north end of the lagoon system and over the course of several hours literally watch the water level drop as the wind blows the water to the south.

Fishing the flats during these conditions is a complete waste of time. The fish have moved to thermal refuges where their bodies can better adjust to the falling water temperatures. In the deeper water the temperature will still drop, but it occurs more gradually. This causes less shock to the fish.

These thermal refuges include canals, dredge holes, power plant outflows, and perhaps the Intracoastal Waterway channel. Just the mass of water in these types of places supplies some insulation and moderates the temperatures.

If you find a concentration of fish in this situation fishing can be ridiculously easy. The fish don’t find much in the way of groceries in these types of places, though. The groceries are up on the flats.

This brings us back to a statement made above: when conditions are right the shallows will be full of fish. What are those conditions?

A strong front has passed. Daytime highs have been in the 50s, nighttime lows in the 30s. The wind has been howling out of the northwest at 20 or so. And then, it stops blowing. The sun is out. No wind. No clouds at all. Go fishing. Now. Let nothing stop you.

Solar radiation quickly raises the temperature of shallow water three of four degrees. The fish, all of them, have been trapped in deep water for two or three days, with nothing to eat. The fish, all of them, come swarming up onto the flats to sun themselves, to get warm, to find food. Be there that first day the weather moderates and you could have the best fishing of the year.

Subsequent days are never as good. I don’t know why not, but I have observed it for years. Sunny days when the wind still blows are not as good. I don’t know why not, but I have observed it for years.

Now, understand that the fish are hungry but the water is still below their preferred temperature. They will eat but generally they prefer smaller meals. Shrimp and crabs are easier for them to digest then smaller fish. Smaller, darker colored baits seem to work better in this circumstance than large or brightly colored baits. Experimentation is still the name of the game, though. If I were a fan of large, brightly colored baits that’s certainly what I would try first.

Redfish and seatrout behave differently. Seatrout will usually be sunning themselves over white spots surrounded by seagrass. Where you find one there will usually be a bunch. These are big fish, 24 inches and over. I don’t know where the little ones go, nor do I care.

Under these circumstances it’s possible to sight fish for big trout, hard to do the rest of the year. The fish, lying in shallow water, are very spooky. The splashdown of something as small as a Clouser Minnow spooks them every time. If fly fishing, an unweighted streamer or a quiet surface fly like a gurgler or slider works well. Spin fishermen would use a soft plastic bait like a four inch jerkbait or a DOA Shrimp, casting beyond the sandy hole and reeling the bait over it.

If you spook the fish they’ll move, but generally will stay in the area. After resting them you may get another chance.

Redfish offer a wider range of behaviors. They could be tailing. They could be cruising. A cruise may be parallel to a shoreline (the fish may have its back out of the water) or may be a circular route, in to shore and back out, then back in again.

They could be singles, or in schools of hundreds. They could be laid up on white spots too, although this is not usually a good thing. You want to see them active and feeding.

In our lagoons if you spook a redfish, or a school of them, the game is usually over. When they’re aggressive after a front passes though, that may not be true.

When fly fishing try shrimp or crab imitations. Spin fishermen should try small jerkbaits, jigs, DOA Shrimp, or the always reliable Johnson Minnow.

Some fishermen curse cold fronts. I love them. My ideal winter would see one pass through every week, keeping the fishing on fire for the entire season.

See you on the water.

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Copyright © John A. Kumiski 2022. It is illegal to reproduce or distribute this work in any manner or medium without written permission from the author, John A. Kumiski, 284 Clearview Road, Chuluota, FL 32766 (407) 977-5207.