Crayfish, the fresh-water lobster

StoryImage( ‘/Images/Story//img-lrHHIV7XrY.jpg’, ‘Photo by Dr. Robert A. Hedeen’, ‘The pincers of a crayfish can give a painful nip.’);

The crayfish (sometimes called crawfish or crawdad) belongs to a vast group of animals termed decapod crustaceans that includes such familiar forms as lobsters, crabs, and shrimp.

The crayfish is a formidable looking beast, with eyes located on the ends of stalks, two sets of antennae or feelers, and large, pincer-like claws capable of inflicting a painful nip if the creature is handled carelessly. Its protective skeleton is on the outside of the body, and, because its principal method of locomotion is backward, it doesn’t care where it is going but is more interested in where it has been.

Many species of crayfish are found in the United States with some 24 types in Illinois. The most common species in the Rock River Valley is the so-called northern green crayfish (Orconectes virilis), which is familiar to anglers as being one of the best baits to be used to catch small mouth bass, and to a few gourmands who have dined on their tail-like abdomen.

Crayfish are found in all of our unpolluted streams, lakes, ponds and rivers. They breed from spring to fall, with differing times for different species. During the mating process, the male deposits a packet of sperm cells in a pocket on the underside of the female. Just before passing eggs out of her body, the female cleans her abdominal legs (the swimmerets) and exudes a sticky substance to cover them. When each one of the 200 to 400 eggs passes from her body, it is fertilized by a sperm cell released from the packet previously deposited by the male, and is attached to the swimmerets.

A female carrying the fertilized eggs on the underside of her abdomen is said to be “in berry” as the dark-colored eggs resemble small berries or lead shot. By slowly waving her abdomen, the eggs are aerated and hatch in about two weeks. The young crawdads are reluctant to leave the protection of their mother, and hang onto her body for a considerable time. The crawdads only leave when this suit of armor has hardened sufficiently to offer them protection from predators.

The crayfish (most biologists prefer this name to crawfish or crawdad) has a love-hate relationship with man. But most of their bad habits are forgotten when one sits down to feast on them or lands a small mouth bass the crustacean lured to the hook.

Many crayfish dig burrows, which may be several feet deep, on the banks of ponds, streams, in swampy areas or fields. The lower part of the burrow contains water, but the outside opening is above the water level and is usually surrounded by a chimney-like pile of dried mud.

Crayfish are so common in parts of the Mississippi Delta region that certain crops cannot be raised profitably unless the culprits are reduced in numbers. It has been estimated that farmers are prevented from using as much as 1,000 square miles of good, tillable land because of these pests. In addition, crayfish feed on young plants (they are especially fond of rice), chewing up an entire field in a single 24-hour period.

Millions of pounds of these succulent crustaceans are harvested and consumed as food each year in the United States. Appearing on an ever-increasing number of restaurants, their price as an entrée rivals that of prime rib or lobster.

Crayfish and catfish farming has been a viable part of the agricultural economy in many Southern states for decades. A large Southern species, the red river crawdad, is preferred for aquaculture, but would have a difficult time surviving in cold Northern winters. However, there is no reason why enterprising farmers in our area could not make an economic success of rearing the Northern green crayfish in a rather deep pond on their land. The potential is there. It would take seven to 13 of the Northern crayfish to make a pound that could be marketed as food or bait.

Analysis of the abdomen (tail) of this crayfish reveals it is composed of 30 percent protein and only 4-6 percent fat.

A word of warning about an alien species is indicated. The rusty crayfish is an introduced species into Illinois from its native Tennessee, Kentucky, and Ohio. It is a prolific breeder and can decimate an aquatic ecosystem by destroying aquatic vegetation. It is illegal to possess living rusty crayfish in Illinois, except with a special permit.

One of the favorite pastimes I enjoyed as a boy growing up in North Texas was to go crawdad fishing. A piece of bacon on a string was lowered into the burrow and, when you felt a nibble, the crustacean was slowly pulled from its lair.

Does anyone remember that once-popular folk ditty that goes in part, “You get a line, and I’ll get a pole, and we’ll go down to the crawdad hole”?

Dr. Robert Hedeen is a former resident of Maryland’s eastern shore and resided in the Chicago area from 1960 to 1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.

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