June 05, 2014
By Larry Cofer
The spring habits and haunts of the toughest cats in freshwater were partially exposed in the April 2000 issue of Catfish In-Sider. An article titled "Prime Time Flatheads" synthesized the keen insights of In-Fisherman editors Doug Stange and Steve Hoffman, along with Ned Kehde, John Thompson, and the late, great Toad Smith. Now those secrets can be compared with a recent upgrade to the scientific database on flathead habits, from a study based in west Texas.
Kehde described Thompson's tried-and-true spring exploits in midwestern reservoirs, where he uses loglines, a beefy form of limbline attached to the trunks of flooded trees. Stange pinpointed spring flathead locations in a small natural lake in Minnesota. The narratives shared a central theme: that flatheads this time of year can be found in heavy cover at moderate depths.
Rob Weller and Jimmy Winter, former graduate students at Texas Tech University, have taken the science of flathead location to the next level. In a recent issue of The North American Journal of Fisheries Management, the biologists published their conclusions about seasonal habitat use and home range size of flatheads in a high plains reservoir. What they learned about prespawn location can make this season more predictable and more profitable for anglers looking for a whiskered trophy.
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Tracking Flatheads
It's long been understood that flatheads establish and maintain definite home ranges around heavy cover in rivers and lakes. For three decades, scientists have occasionally tagged and tracked flatheads in waters across the country, and they've agreed on two major conclusions: flatheads have well-defined territories, and those boundaries always encircle some kind of heavy cover.
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Home range tendencies in river systems are just as dramatic. In a Mississippi River study, all but one tagged flathead were found less than a mile from their capture site. In the Apalachicola River, 96 percent of recaptured flatheads were found in the same river stretch where they were originally tagged. And a tracking study in Mississippi found that flathead home ranges averaged less than half a river mile.
In the Missouri River, researchers found that flatheads consistently selected snags over open water. In other studies, scientists on the Mississippi and Missouri rivers found that flatheads preferred wing dams. As a budding biologist in Georgia, ÂIn-Fisherman's staff fishery biologist Steve Quinn determined that introduced flatheads in the Flint River were most abundant in rocky reaches. The rules are simple — find cover, and you'll likely find flatheads. And if you find them once, you'll likely find them there again.
Weller and Winter conducted their study in Buffalo Springs Lake, a muddy, 235-acre impoundment near Lubbock. They captured fish by gill netting and electrofishing, then surgically inserted radio transmitters in 29 flatheads weighing from 2 to 40 pounds. For two years, the researchers doggedly tracked individual signals of all the flatheads and recorded data on location, bottom type (rock, silt, or wood), depth, and water temperature.
In their report, they summarized tracking data from each major season. They defined the spring season as a time from postwinter when the lake was warming up to the spawning period. Nesting occurred in Buffalo Springs from mid-June through mid-July, when water temperatures ranged from 68ËšF To 77ËšF.
Cold Tracks
A thorough review of spring preÂspawn habits and locations of monster flatheads must begin with the winter thaw and end with their eventual transition to spawning sites during midsummer. The winter fishing season for flatheads has perplexed even the most talented anglers. That is, if it can even be considered a season. Most ardent flathead specialists take the winter off, stowing their gear and resting their forearms for warmwater battles with cranky cats.
Between fall, when flathead fishing is satisfying and predictable, to midsummer, when flatheads move to well-known spawning areas, lies a mystical world where few have ventured and even fewer have prevailed. We can now turn to science for a partial answer to the winter flathead enigma.
In deep winter, flatheads lie almost dormant in their native waters from Minnesota to Alabama, and from Kentucky to Texas. Tracking studies prove that flathead movements in cold water are minimal. These are not cold-Âtolerant creatures like their genetic cousins the blue catfish. Blue cats turn on in winter like Las Vegas on a Saturday night, but flatheads shut down tighter than Mayberry on a Monday night.
At the southern end of the flathead's range, or where they've been introduced in the Apalachicola River, adventurous anglers can catch a few regardless of the season. Jigging soft plastics near the bottom during warm spells might produce fish in the north, too, but for most of us, winter and flatheads just don't belong in the same sentence.
The study at Buffalo Springs resolved most of the winter wonder for flathead anglers. A shallow lake in the Texas plains is completely exposed to cold Canadian fronts, and by December, flatheads in Buffalo Springs had moved to their deepest haunts of the year. They didn't select the deepest part of the lake (48 feet), though, settling instead to the bottom at a moderate depth from 22 to 28 feet deep. Water temperatures in winter averaged from 40ËšF to 45ËšF.
An earlier study in Minnesota found that flatheads captured in winter had mud on their backs. Weller and Winter noticed that transmitter signals were weaker than usual for fish that settled to silted bottom zones in winter. The scientists guessed that some flatheads might be burrowing into the bottom mud in winter. This makes sense for the fish, since the sediment can be five degrees warmer than the water above.
That's not to say that flathead fishing is a dead issue in early or late winter. Steve Hoffman expanded our frigid frame of reference on cold-weather flathead tactics two years ago in the January 2000 issue of Catfish In-Sider. Hoffman described the revolutionary exploits of a Wisconsin angler named John Lehto, who had refined a technique for catching big, lethargic flat cats in cold water.
Of course, in Wisconsin the term cold must be treated with some degree of respect. Lehto was finding success in water colder than 40ËšF, before and after freeze-up in the frigid north. In the south, it's not at all unusual to find water in the 40ËšF range, even when winter is deeply entrenched. That makes Lehto's technique of jigging with soft plastics an almost year-round possibility for many flathead anglers.
In winter at Buffalo Springs, home ranges for flatheads were definitely the smallest of the four seasons, but that doesn't mean they were hibernating like bears. Territories averaged about two acres, and one fish moved in an area of 12 surface acres. These movements indicate activity, and any top-level predator stays active in the winter for one major reason: to eat. This means that flatheads are vulnerable to anglers almost year-round, though they certainly are toughest to catch in cold water.
Spring Tracking
Obvious from this and other studies is that fishing in open water is a serious mistake for flathead anglers. In the West Texas reservoir case, it could be said that open-water anglers have only a 20 percent chance of encountering a flathead, even if they're using the right bait and fishing at the right depth. On the other hand, anglers who select areas with cover have an 80 percent chance of being in the right zone, which is significantly smaller than the wrong zone.
These tendencies hold, wherever flattops are pursued. Doug Stange and his legendary fishing partner, Toad Smith, knew their odds when they fished that little lake in Minnesota on a spring night several years back. They selected shallow structure near deep water, where flatheads shaking off winter's chill could ambush bullheads and bluegills after dark. Their luck that night was based on decades of experience that has since been verified by several scientific studies.
When John Thompson's tactics on Kansas reservoirs were described by In-Fisherman magazine contributor Ned Kehde, it was no accident that the veteran catter chose areas of moderate depths, near deep water and choked with heavy timber. Thompson didn't need science to verify his well-honed techniques with trophy flats, but maybe the blend of science and savvy will inspire others to stay tight to cover, in mid-depth zones where flatheads lurk this time of year.
In early and late spring, anglers will find flathead populations in a state of flux. Not every flathead emerges from the winter depths on the same day, or establishes a spring territory overnight. Likewise, not every swollen female or juiced-up male will swim to a favorite cavity for spawning on the same magic day. In these edge weeks, portions of the population will still be in the old mode, while others are moving toward the new pattern. But during prespawn, feeding is the primary motive, and trophy flatheads are approaching their annual peak weights.
Spawning Tendencies
In late spring and early summer, flatheads in the Buffalo Springs tracking study continued feeding and moved to traditional spawning structures. Like any catfish, flatheads prefer darkened cavities for procreation. The difference is in the dimensions. A hollow limb might suffice for a channel cat, but trophy flatheads need large caverns to match their proportions. And the biggest, baddest cats select the best spots.
Bigger fish in any population select for the best nesting cavities, but they also move in to spawn first. That means that to catch trophy prespawn flatheads, anglers must start early — perhaps much earlier than ever considered before. Wherever flattops prowl, spawning begins when water temperatures reach about 75ËšF. In the deep south, that might mean late May; in the Midwest, it's usually late June; and in the North, late July or even August. That puts the prime trophy fishing period somewhere between April and June, going from South to North.
In west Texas, that warmwater spawning period is mid-June to mid-July. In Buffalo Springs Lake, Weller and Winter found that flatheads nested consistently from six to nine feet deep during spawning seasons. After waters warmed to 70ËšF, they found almost every flathead near the dam at one time or another, where rocky riprap was available for nesting cavities. PreÂspawn and postspawn flatheads continued to use wood cover, and some were occasionally found over silt. Chances are the fish in silt-bottom areas were simply in transition from one cover area to another.
After the spawning season, summer home ranges for flatheads in Buffalo Springs were the largest of the year, ranging from 8 to 125 acres. The summer average was 32 acres. Summer territories were shallower than at any other season, even though water temperatures in the muddy lake topped 80ËšF. While other gamefish species retreat to deeper, cooler water in summer, it's obvious that flatheads relish the steamy shallows.
As water temperatures declined in fall, flathead activity moved again to mid-depths and then shifted to deep water as winter set in. Fall patterns and haunts can be expected to mimic spring preferences — middle depths, where shallow cover intercepts deeper water.
A few nuances of flathead behavior are worth noting from the Texas Tech study. Weller and Winter found that home range size did not differ much for males or females. Also, they found no difference in territory size that could be related to the size of the subject fish. In fact, their largest test subject, a respectable 40-pounder, had the smallest home range. Her territory encompassed an area just the size of a city block. When targeting trophy flatheads, therefore, an angler might be looking for a range that includes less than one percent of a reservoir's surface area.
The study authors suggested that big flatheads don't need large ranges because they select and defend the best habitat, where cover, temperature, and food are optimum. Flatheads, in fact, are known to be cannibalistic and won't share territories quietly. A single brushpile in a river or lake likely will hold only one large flathead. A single rock outcrop likely will hold only one sizable fish, too, at least until the spawning season arrives and nesting activities override the need for solitude.
Anglers should understand that flathead feeding activity peaks at night, and the best fishing therefore comes after dark, as it did for Doug Stange and Toad Smith. The day versus night difference might not be significant in muddy lakes like Buffalo Springs, but in clear lakes, flatheads are largely nocturnal.
Within any given cove or lake arm, flathead abundance is directly related to cover density. The more dense the cover, the more big flatheads a body of water will support. Weller and Winter noted that good cover in Buffalo Springs Lake was limited, and they suggest that managers can increase flathead numbers by placing riprap and brushpiles in prime zones. In fact, some managers have found that the same brushpiles they build for crappies and bass also will support catfish.
Now that the science of early season flathead action is in public hands, all that remains is to put the knowledge to work. History dictates that a little knowledge can be dangerous, though, and evolving wisdom holds that big flatheads are rare, deserving more conservation as more people understand and exploit their seasonal patterns.
We should note that the findings of Weller and Winter were from a small, turbid reservoir with a small population of flatheads where movements were artificially limited. Confirming those conclusions in major reservoirs and clear natural lakes over the rest of the flathead's range are further steps to be taken by fisheries scientists.
Meanwhile, it might be more exciting to verify those patterns on a wider scale with a stout rod and reel. Maybe we should do a little hook-and-line surveying with some livebait and an 8/0 circle hook, while we wait for the next tracking study to be published.
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