Crayfish: Indicator of the Health of the River and Food of Sport and Game Fish

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Astacology is the name given to the study of crayfish, the freshwater crustaceans that dwell within the streams and rivers and are an indicator of the health of the river...

Astacology is the Study of Crayfish

Crayfish are small lobster-like crustaceans that live in rivers and streams with adequate shelter and gravel or stony bottoms. While they feed upon virtually anything included dead and heavily decayed protein matter, they are very intolerant of muddy, silty or polluted waters. Their presence (or absence) in a river or stream environment (like indigenous freshwater clams & mussels, etc.) provides a vital clue to the health of the river, pollution levels and changes in overall water quality.

Crayfish are Bait, Food

Because crawfish are a primary food source of some species of fish such as smallmouth bass, their presence is an indicator of healthy biodiversity. Pollution and silt runoff from logging, agriculture or other human activity can cause the crayfish pollution to suffer or die-off which in turn causes a ripple effect. Other creatures that depend upon crayfish as a food source will suffer in the long-term absence of crayfish. This includes but is not limited to game & sports fish, turtles and river otters.

Even unpaved transportation and causeway access ('dirt/dirt & gravel';) roads play a part in river silting which can affect the overall health of the river and all its inhabitants. If crayfish cannot survive because of excessive silt in the stream, the fish and other creatures that depend upon them for food also suffer.

Crayfish are given various other names in local regions throughout the world. Names such as lobsters, crawdads, etc. ‘Mudbugs’ in the southern United States is a common name used while the term ‘crawdad’ is more commonly used in the central and western United States.

crayfish, also called crawdad and mudbug

(image source)

Crayfish are an edible commodity for humans too with the state of Louisiana being the larger producer and exporter of these edible delicacies in the U.S. It is a delicacy for the French population that settled there. Boiled in a pot with seasonings, potatoes, onions and other vegetables, they are a local favorite food. Cajun and Creole cuisines regularly feature items such as crawfish pie, beignets and other entrees that include crayfish protein.

Crayfish Turn Bright Red when Cooked or Boiled

crayfish turn brilliant red like lobster when cooked or boiled

(image source)

A dish favored by the French military leader Napoleon Bonaparte which was hastily prepared by his personal chef after his army had won a major battle victory, features crawfish. ’Chicken Marengo’ was named after the victory in the Battle of Marengo (during the Italian Campaign, June 1800) and was according to legend, prepared hastily with chicken, eggs, tomatoes, garlic & onions, crayfish, olive oil and seasoning spices. Napoleon allegedly liked the dish so much and considered this new dish a good omen after having just won such an important battle that he decreed all the hastily-gather ingredients used in this impromptu meal (including the untoward inclusion of crawfish) to not be omitted in future preparations of this dish.

Crayfish are a Favorite with Anglers for Bait for Game/Sport Fishing

Crayfish are commonly used in sport fishing as it is a favorite bait of such fish as smallmouth and largemouth bass, pike, the large channel catfish and the muskellunge (a.k.a. “muskie.”)

Usually the claws are removed from the bait prior to applying to the angler’s hook so as to not allow the defensive postures of the still-live crayfish deter the fish from taking the bait. ‘Live baiting’ is in some regions an illegal activity. Apart from the ‘animal rights’ concerns, if the bait creature is an invasive one (not naturally indigenous to the region) its possible escape can create problems for the local environment.

Introducing non-native species of any creature (including the crayfish) can have disastrous results. Some crayfish species carry a disease called ‘Aphonomyces astaci’ or simply put a ‘water mould’ disease. European crayfish die with weeks of exposure, and it is believed that all crayfish species are susceptible to this crayfish plague in at least some varying degree.

Introducing any non-native species to a new habitat under any circumstance is almost always a bad venture for the indigenous life already present, no matter what the intention was.

Crayfish ‘live bait’ as a Potential Vector for Zebra Mussel Proliferation

a crayfish covered with zebra mussels, an invasive species

(image source)

Zebra mussels for instance (another unwanted and invasive species) have been known to attach themselves to the carapaces of crayfish which in turn navigate up waterways to invade upstream reservoirs such as lakes and tributaries. A non-native crayfish that escaped the hook and predators can eventually find its way into virgin streams that lead into the river or lake. Having survived to angler's hook, they can migrate upstream. Even traveling briefly across land to new land-locked water reservoirs otherwise denied to both them as a species and the hated zebra mussel. Generally for these and other reasons it is only permissible for sport-fishing bait to be ‘euthanized’ immediately prior to use or as a matter of consumer supply, only available for use as frozen or salted to begin with.

Any managed waterway or aquatic resource should include priorities that will ensure native creatures such as the crayfish remain healthy and present in the local environment. Their presence in a healthy waterway contributes to economic, cultural and recreational benefits for everyone.


Posted on Aug 11, 2010
Martha Alguera
Posted on Feb 25, 2010
Johnny Dod
Posted on Feb 19, 2010
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Lauren Axelrod
Posted on Feb 18, 2010