February through May is the first major period of crawfish activity, based on geographic location. When the water temperature reaches approximately 50 degrees, crawfish emerge from rock crevices into the great wide open and begin looking for receptive females.
Many of the emerging crawfish males and females are still sexually active from the previous fall. What’s significant about this two to three week period in spring (depending on rising water temperature), is that it’s one of the few times males walk on top of rocks, exposing themselves to bass.
Trapping studies have revealed that below 45 degrees, crawfish have little to no activity while buried in mud burrows or rock crevices. But when the water rises to 50 degrees, it’s a whole new ballgame.
Where will bass be picking off these vulnerable mudbugs? Rocks will point the way. It may sound oversimplified, but rocky substrate has the highest concentration of exposed crawfish, which in turn translates to the greatest numbers of feeding bass.
Prime conditions in most bass watersheds combine 50 degree average water temperature with rocks clean of silt or mud. Unlike bass that clean their spawning ground with their tails, crawfish rely on current or wave action to do their housework. The rocks must be clean to open up caves that can create endless lattices of spawning habitat. That may be at 3 feet of water on a wind-swept point, or at 30 feet on a small hump in the middle of the lake. Whether you’re fishing in Alabama in February or Michigan in May, the formulation of season, clean rock and ideal temperature is guaranteed to attract most of the mating crawfish — and feeding bass — in the area.
Depending on the species, crawfish can and will spawn in mud. However, they rarely do so if clean, rocky habitat is available.
One of the ways bass locate crawfish is by sound. “A crawfish moving on a rock makes a tapping/clicking noise. Bass use this sound to locate crawfish," said Tertuliani.
Crawfish also are light sensitive. Water clarity and penetrating sunlight are key ingredients to active, quality habitat. If the prime habitat happens to be in shallow water or is more exposed to direct sunlight, low light or cloudy days often provide better fishing than bright afternoons.
After mating, the females burrow into a cave and fertilize their eggs with the sperm that has been deposited on them by the males. The males then molt, losing their calcified sexual organs, and quickly hide. “The molt" as it is often referred to, is supposed to be the time bass gorge on crawfish. This may not be the case. “Many anglers associate molting with intense bass activity on crawfish baits in the spring. And actually, this spike in activity is most likely due to the vulnerability of crawfish during the mating cycle," said Tertuliani.
After the molt, males return to a reclusive pattern and are not as available to bass as they were when they were mating. They will feed in their cave burrows if possible, and only expose themselves in the evening or in low light conditions.
The molt will dramatically change the color of crawfish from a camouflage olive/brown, to a bright orange or red cast, making them an easy visual target for bass. But understand that a bass must work more diligently, and expend much more energy to catch a crawfish during the molt than during the mating cycle.
Meanwhile, the females will hatch their eggs in 30 days or so (depending on water temperatures). The hatchlings stay attached to the female and molt every two to seven days, depending on species. After the third molt, when they reach approximately one-half inch in length, they fall off their mother. The females quickly molt and go into a quiet summer low light feeding pattern, staying in the rock crevices as much as possible.
The little crawfish fall into the rocks, where they molt multiple times and eat, until the fall — when most become adults, depending on the length of the growing season. During their early summer growth period, the greatest threat to the juvenile crawfish comes from chubs and bottom feeders, not bass.
When fall arrives and you’re throwing a shad imitation, revisit the rocks you fished in the spring with a crawfish bait. The fall mating cycle is actually the most intense, and often is completely ignored by bass anglers. The process can be especially intense in southern latitudes. The fall mating period is made up of all the adult crawfish that are sexually mature. There are species exceptions, and temperatures falling too rapidly below 45 degrees can shut it down early, sending the crawfish into a dormant state.
Fish the fall the same way you fish the spring, and you’ll find the fall mating cycle is a bonanza.
The research group at Pure Fishing in Spirit Lake, Iowa, is actively seeking information on crawfish behavior. Pure Fishing manages one of the largest live fish behavioral test facilities in the world, and statistically measures fish reaction to baits and key foods.
“We are amazed at many of the findings that have been discovered in our facility in the last few years," said John Prochnow, Product Development Manager. Led by Dr. Keith Jones, multiple tests were made with live bass over several months in a controlled environment to measure what kind of shape the bass preferred when keying on soft plastic crawfish imitations.
For 60 days, 450 largemouth bass, plucked from the same environment, were tested using a robotic arm and a strike counter. Each group of bass was presented a crawfish bait at the same speed and angle of attack. The bass tested had never seen the bait that was presented (it was a prototype). The test then continued, with one pincer removed, then a second pincer removed, and finally, the legs. The soft bait that had no appendages (no legs or pincers, just a body and tail) had the greatest number of strikes.
“The final bait looked almost like a large shrimp," said Proctnov. The research was incorporated into the Berkley Flippin Tube. “We wanted to market a craw with no appendages, but our market research said no one would buy it," Proctnov added.
Crawfish live on the bottom. That’s not to say you can’t catch a bass in open water with a crawfish bait. But a live crawfish will not leave the rocks unless it is forced to.
During the summer, bass feeding patterns shift to low light or darkness. Again, bouncing a plastic craw over prime habitat in daylight hours can result in catching bass that are keyed in to the pattern, waiting for a midday meal. But for consistent action during dog days, move to deeper, darker rock substrate.
One of the best ways to fish crawfish baits, hard plastic or soft, is to work them parallel to rocky banks, changing depths until you find fish. One of the most important elements of making a believable presentation with a crawfish imitation is to keep contact with the rock or cover you are fishing. The ticking of a crankbait bill or lead sinker against a rock imitates the clicking of real crawfish — enticing bass to strike. Plus, contacting the cover ensures your bait is hugging the bottom, where crawfish live. Add internal rattles to plastic baits, and allow the bait to sit for an extended period of time. Small shakes of the rod tip will activate the rattles, drawing bass to your offering.
Most importantly, follow closely the rituals of this favorite bass forage, and you’ll be catching bass on crawfish baits because of knowledge, not just luck.
Curt Samo, a fishing pro from Rockford, Ill., takes the guesswork out of color and size. In every lake or river system he fishes, Samo launches a crawfish trap the day before the tournament he is fishing. He uses a simple South Bend Crawfish Trap, and stops at the local convenience store on the way to the lake and buys cat food for bait.
“I walk several yards down the bank from the boat ramp, because it’s almost always a rocky shore, set the trap and leave it overnight. In the morning, I pull the trap and see the color and size of the local population, match the baits and get to work. On a northern lake, Samo found an almost fluorescent orange crawfish occupying the trap. “I changed baits, matched the color and have cashed a check in 90 percent of the tournaments I’ve fished on that water since," said Samo.
John Tertuliani, a biologist for the U.S. Department of the Interior in Columbus, Ohio, completed his Masters thesis on freshwater crawfish, and is on the cutting edge of crawfish behavior relating to bass. Tertuliani’s research was instrumental in developing this story.