The Truth About Crayfish – What Anglers Need to Know

Of the more than 640 species of crayfish (crawfish, crawdads, mudbugs) known worldwide, about 400 live in fresh waters in the United States. Most occur east of the Rockies, and the greatest diversity is in the Southeastern states. Many crayfish live in streams, rivers, lakes and reservoirs. Others live in springs, swamps and other temporary waters, and caves. The focus here is those in permanent waters where anglers fish, and crayfish are ubiquitous in these waters.

Crayfish are eaten by all predator fish, and they rightfully can be considered bass candy. They live on the bottom in deep and shallow water. And they are often abundant, with standing crops of 200 to 500 or more pounds per acre in productive lakes or streams with good habitat, several times the biomass of the fish that consume them in the same water.

As would be expected from such a diverse group, crayfish come in many sizes, shapes, and colors. Adults typically range from two to three inches body length, from head to tail, excluding the chelae (pincers). Body shapes are slender to robust. Some have smallish chelae. Others are armed with very robust chelae. As a group, crayfish are colorful, some even vibrant. Some species are predominantly blue or blue and purple, others a bright green, and many with distinct red or blue markings. But most are rather drab to remain hidden in their environment.

Many anglers think red and orange are crawfish colors. Maybe because they’re thinking of the red swamp crawfish, which are dark red and black, they ate at the last crawfish boil. Or maybe they are trying to match the color of a partially digested craw that a bass just regurgitated in the livewell. That could be misleading because the process of digestion affects the pigments in the crayfish skin the same way as boiling turns a lobster red.

Accomplished bass pros Dion and Guido Hibdon were noted for capturing crayfish from tournament waters and hand-tying jigs to perfectly match their colors. A very ambitious effort. Although colorful as a group and with much variation between and within species, the majority of crayfish in lakes and rivers are olivaceous (think green pumpkin) or tan to light brown (think pumpkin pepper). With most lakes harboring multiple species, these two colors are a good default crayfish mimic unless you luck into a bass willing to part with a freshly ingested crayfish or want to get wet turning over rocks.

What about seasonal color changes? Red and orange hard baits, like the BOOYAH Hard Knocker or Bomber Deep Flat A are proven bass catchers in the spring. Numerous websites attribute bass’ preference for red to crayfish color at this time of year. These are all fishing websites. A deep search of the scientific crayfish literature revealed that some crayfish can change color to better blend with their background, that males may be more brightly colored during mating season (which is usually in the fall), and recently molted crayfish are often lighter color. What I did not find was any reports of red-phase crayfish in the spring. The take away message: Keep fishing red and orange colors if they work in your waters, but don’t count on the notion that you are mimicking a spring crayfish.

Most crayfish mate in late summer or fall. The male deposits sperm in the female’s sperm receptacle where they are stored. Eggs are fertilized when released, which varies among species but commonly occurs in the spring in temperate-zone species. The female carries the fertilized eggs glued to small appendages on the underside of her abdomen. A female carrying eggs (developing embryos) is termed “berried” or “in berry” because the cluster of eggs looks like blackberries. Depending on species and age, a female may carry a couple dozen to more than 700 eggs. The berried female remains in hiding until the eggs hatch, which could take from two to ten months depending on crayfish species and water temperature.

The young resemble tiny crayfish when they hatch. They grow quickly. Their hard, protective exoskeleton (shell) does not grow or stretch. As crayfish grow, they shed the existing exoskeleton (molt); underneath the old exoskeleton is a new, soft exoskeleton that allows for growth and then hardens over a period of several weeks. Lacking their hard exoskeleton that both protects them and makes their chelae useful feeding tools and defense weapons, these highly vulnerable “soft shell” crayfish are especially secretive. Molting may occur six to 14 times during a young crayfish’s first year as they quickly grow to small adult size. Molting occurs less frequently for adults, decreasing to one to three molts per years for older adults.

Depending on species and climate, crayfish become sexually mature at age 1 or 2.  Although some Australian crayfish live as long as 30 years, most crayfish in the U.S. live two to six years.

Survival is job one. Although seemingly well armed with large claws and able to rapidly scoot backwards a foot or more when startled, crayfish are highly vulnerable to large predators like largemouth and smallmouth bass. Their survival depends on remaining hidden among and under rocks and logs or camouflaged on the bottom. Like fish, crayfish, have habitat preferences. One study in Lake Tahoe found crayfish densities in rocky areas double those in areas of vegetation and ten times greater than on bare sand flats. Different species will have different habitat preferences, but some form of cover will usually be selected. To better ensure survival, they tend to be more active at night than during the day.

Crayfish are opportunistic feeders, eating both dead and living plant and animal matter. The young crayfish tend to be more carnivorous, feeding on aquatic insect larvae. Crayfish do consume zebra and quagga mussels, unfortunately not at a rate sufficient to suppress these unwanted, non-native mussels.

Crayfish walk forward and escape backwards by tail flips―rapidly flexing their tail section and pulling their telson (tail fan) under their body to propel themselves up to a couple of feet per flip. Something to ponder when you are fishing a soft plastic craw mimic like a YUM Craw Papi on the bottom or selecting and retrieving a craw-imitating crankbait. When you catch a bass with a crayfish in its stomach, invariably you see the chelae sticking out from the bass’ throat. Dr. Brian Roth, crayfish expert at Michigan State University and an avid angler, has observed that fish often ingest crayfish tail first as they are tail flipping, and they may nip at the crayfish to induce movement to get a tail-first bite.

Multiple mark-recapture and tracking studies suggest crayfish generally don’t move far on a daily basis. Little is known about crayfish seasonal movement, but one study found crayfish in Lake Tahoe moved to deeper water in the winter. Although crayfish usually move only short distances daily, they can walk up to a couple hundred yards a day when active. An interesting―unusual may be a better term―phenomenon that I observed in two different Minnesota lakes in mid-summer is a mass movement. Afforded a good view by the clear water, I watched many thousands of crayfish walking across a mostly barren, shallow sand flat. It appeared like a crayfish-patterned carpet was being slowly pulled across the bottom. Especially unusual is that these movements occurred at mid-afternoon, in bright daylight.  Not a bass was seen enjoying the unlimited buffet. I have not been able to find an explanation for the events.

Crayfish do not become dormant in the winter; but, like most cold-blooded animals, their activity diminishes. Some researchers have suggested feeding stops, and they stay hidden. How much their activity decreases and they stay hidden will vary from southern to northern waters, but it is reasonable to conclude that fewer crayfish are consumed by bass in the winter. But that doesn’t mean bass’ appetite for crayfish has diminished, and a slow-moving crayfish mimic may be just what it takes to trigger a strike from a lethargic cold-water bass.

About the Author: Hal Schramm is an avid angler and retired fisheries educator and research scientist. For 40 years he taught graduate and undergraduate fisheries management courses. His research focused on large river fisheries ecology and warmwater fisheries management. 

• Rebel Wee-Crawfish – a longtime favorite craw-imitating hard bait that is especially popular for stream fishing
• Rebel LIVEflex Creek Craw – new to Rebel, with natural shaping, buoyancy, toughness and fluid motion
• Great Lakes Finesse Juvy Craw – tube style, with crayfish shaping; ideal for moving along the bottom
• Bandit 200 – Bone Craw Series – natural markings, sized right to match many craws and well suited for grinding rocky bottoms
• War Eagle Heavy Finesse Jig/YUM Salt Craw – subtle and natural and excellent for working every bottom contour
• YUM Spine Craw – narrow profile and quick claw movement equip this craw for a range of applications