Welcome to Not Quite Entomology

Welcome to Not Quite Entomology! This is a different approach to matching the hatch, or learning which insect the fish are really eating. The flies and methods to make it all work will be here as well. We hope this series will inspire you to go out, look on top of and under rocks, check the stream-side vegetation, really investigate your favorite water and learn which are your local trout's favorite foods!


By LadyFisher


Maybe you've seen crayfish (or crawdads) in your local waters. Kids tend to try and catch them.

More serious adults catch or raise them for food. At one time catching them for bait was a very popular thing - but that has been discouraged since the Rusty crayfish can really take over and decimate a place where they have been unknowingly introduced. Some states have made it illegal to possess live crawfish while having angling equipment in ones possession. The rusty crawfish is very aggressive and will displace native crawfish species as well as underwater plants and other invertebrates.

My first experience as an adult with crawdads was in a restaurant outside Savanna Georgia where the house special was big pots of boiled, drained crawdads were dumped out on newspaper covered tables with steamed corn and containers of melted butter. Wish I could remember the name of the place! It was flat wonderful. We do get them in our local supermarkets from time to time.


Crayfish, (Decapoda) also called crawfish or crawdad, are closely related to the lobster. It really is a miniature version of the lobster. More than half of the more than 500 species occur in North America, particularly Kentucky (Mammoth Cave) and Louisiana in the Mississippi basin. Crayfish also live in Europe, New Zealand, East Asia and throughout the world, including the Tristan da Cunha Islands. Nearly all live in freshwater, although a few survive in salt water. Crayfish are characterized by a joined head and thorax, or mid-section, and a segmented body, which is sandy yellow, green, or dark brown in color. The head has a sharp snout, and the eyes are on movable stalks.

The crayfish is typical of most shrimp-like crustaceans and is characterized by a joined head and thorax, or mid-section, and a segmented body, which is sandy yellow, green, white, pink or dark brown in color.

Crayfish are usually about 7.5 cm (3 inches) long. Among the smallest is the 2.5-centimetre-long Cambarellus diminutus of the south-eastern United States. Among the largest is Astacopsis gouldi of Tasmania; its length may reach 40 cm and its weight about 3.5 kg (8 pounds).

The head has two pairs of sensory antennae and a pair of eyes on movable stalks. The appendages, or pereiopods, of the thorax include four pairs of walking legs which, as well as walking, are to probe cracks and crevices between rocks looking for food. Crayfish also own one pair of claw-bearing chelipeds, which it extends in front of its body while moving. These strong pinchers are specialized for cutting, capturing food, attack, and defence. Some can grow to three inches in just the claw length. A pinch can hurt! The crayfish also has several pairs of specialized food handling 'legs,' bailers to cycle water over the gills, and five pairs of swimmerets which are under the abdomen. All of these 'legs' can be regenerated if broken off.

Crayfish have a hard outside skeleton. This jointed exoskeleton provides protection and allows movement, but limits growth. As a result, the crayfish regularly gets too big for its skeleton, sheds it, and grows a new larger one. This is called molting. and occurs six to ten times during the first year of rapid growth, but less often during the second year. For a few days following each molt, crayfish have soft exoskeletons and are more vulnerable to predators.

Crayfish, common in streams and lakes, often conceal themselves under rocks or logs. They are most active at night, when they feed largely on snails, algae, insect larvae, worms, and tadpoles; some eat vegetation (various water plants). Dead fish, worms, corn, and salmon eggs are also favorites of the crayfish. Studies show that adults (one year old) become most active at dusk and continue heavy feeding activity until daybreak. Young crayfish are more likely to be the ones out during bright sunny days, while the older crayfish are more active on cloudy days and during the night. General movement is always a slow walk, but if startled, crayfish use rapid flips of their tail to swim backwards and escape danger.

Most crayfish live short lives, usually less than two years. Therefore, rapid, high-volume reproduction is important for the continuation of the species. Many crayfish become sexually mature and mate in the October or November after they're born, but fertilization and egg laying usually occur the following spring. The fertilized eggs are attached to the female' swimmerets on the underside of her jointed abdomen. There the 10 to 800 eggs change from dark to translucent as they develop. The egg-carrying female is said to be 'in berry,' because the egg mass looks something like a berry. Females are often seen in berry during May or June. The eggs hatch in 2 to 20 weeks, depending on water temperature. The newly-hatched crayfish stay attached to their mother until shortly after their second molt.

The importance of the crayfish in a game fish's diet can be played up or down depending on one's point of view. Down: Studies show that trout eat more aquatic insects than any other item. Up: Biological studies also show that stream-living trout will select the largest prey items that they can swallow. When crayfish are available, they will be eaten!

Crayfish are mostly found in warmer water, but do inhabit streams, rivers, lakes, swamps, ponds and are familiar to any number of game fish. Even in cold trout streams, large trout seem to recognize a good meal!

Because species and crayfish colors vary, it's best to fish with a fly that matches the natural. Fish them in shallow, rocky places, for crayfish favor these areas. Flies should be tied to they can be retrieved backwards, the way that crayfish always swim. Fishing at dawn, dusk, or during the night would best imitate natural movement. The retrieve should be a zip-zip-zip which matches the movement of the repeated flicks of its abdomen.

For more on crawfish and the flies to imitate them, read Al's Crayfish, and Rock's Crayfish. ~ LadyFisher

Credits: Information from, www.mackers.com and Aquatic Entomology by W. Patrick McCafferty, drawing from the same. Photo from The Life of The Pond published by McCraw-Hill.

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