Crayfish

Crayfish inhabit freshwaters of the Northern and Southern Hemispheres but are more common in Europe, North America, Australia, and Asia, where they occur in water bodies like rivers, brooks, swamps, paddy fields, and streams. However, they are not as abundant in the Southern Hemisphere.

These crustaceans go by many names, including mountain lobsters, yabbies, crawfish, freshwater lobsters, mudbugs, and crawdads. Crayfish breathe through feather-like gills, and some species cannot survive in polluted water, but others are stronger.

Crawfish are omnivores and eat plants, animals, and detritus. There are over 640 crayfish species in the world, with more than 400 species in North America, especially concentrated in the southeastern United States.

Three Amazing Crayfish Facts

• Most crayfish species are aquatic, but some species occur in semi-aquatic environments. These crawfish breathe by burrowing into the soil for access to water.
• They have incredible eyesight, and like other related species, they can move their eyes independently from each other.
• These crustaceans are generally nocturnal and mainly feed on insect larvae, snails, amphibian tadpoles, and worms. In addition, they can feed on the vegetation in their habitats.

Taxonomy

These crustaceans belong to the order Decapoda, which consists of over 8,000 species, including lobsters, hermit crabs, shrimp, crabs, and crayfish.

Members of this order are primarily marine animals; however, like crawfish, some species inhabit freshwater. Their numbers are abundant in shallow, warm, tropical waters, but many species are commercially exploited throughout the planet.

Some crayfish species include:

• Red Swamp Crayfish (Procambarus clarkii)
• Dwarf Orange Crayfish (Cambarellus patzcuarensis)
• Blue Crayfish (Procambarus alleni)
• Marmorkrebs (Procambarus fallax)
• Common Yabby (Cherax destructor)
• Australian red claw crayfish (Cherax quadricarinatus)
• Brazos Dwarf Crayfish (Cambarellus texanus)

Appearance

Crawfish are members of the crustacean family and have a body consisting of three segments, which include the head, thorax, and abdomen.

In addition, they have a hard shell or exoskeleton, which they use for support and protection. However, their exoskeletons hinder their growth rate. It’s precisely like outgrowing a pair of pants; therefore, crayfish need to shed their shells and grow a new one, which is called molting. Unfortunately, while they are regrowing their exoskeleton, their soft bodies have no protection from potential threats and predators.

While crayfish species vary in size and appearance, they are generally 3 inches long. One of the smallest crawfish is called Cambarellus diminutus, which only measures 0.98 inches long. These tiny crustaceans inhabit the southeastern regions of the USA. One of the largest species is Astacopsis gouldi, which can grow to 15.7 inches long and weighs around 8 pounds.

Behavior

Most crawfish are generally active at night when searching for food. So, during the day, they retreat to burrows, under rocks, or hide under debris. In addition, these crustaceans are usually very territorial, especially against other members of their species.

When they do engage in battle, they will display the following behaviors:

• Wrestling
• Clawing — A male uses their claws by pinching or jabbing their rival
• Meral spread — when males raise the anterior portion of their bodies in an intimidating stance

Habitat

The majority of the crayfish species are freshwater crustaceans, especially running water like brooks, streams, and rivers. They prefer this type of habitat because their immune systems do not allow them to live in polluted water.

Standing or stagnant water is more susceptible to pollution, as there is no freshwater flowing into it to wash the stale water and decay away.

Diet

Most species of crayfish aren’t picky eaters and will devour anything in their path; this includes both living and dead animals, like:

• Fish
• Shrimp
• Plankton
• Algae
• Worms
• Insects

However, they also eat plant matter that decomposes in the water, like weeds, grass, and tree leaves. But, as mentioned above, they will eat almost anything.

What Crayfish Eat in Captivity

Luckily, nourishing a crayfish in captivity is relatively simple. There is no need to spend hours scouring ponds for plant matter or fishing.

People can buy commercial sinkable pellets online, which include ingredients like:

• Kelp
• Algae
• Salmon

In addition, you can feed them vegetables like carrots, peas, zucchini, broccoli, and Java moss. However, if owners want to take the more natural approach, crayfish will eat any small fish added to the tank. But crayfish don’t need that much protein, so a diet of commercial pellets as their main source of nutrients is more than enough.

Predators and Threats

Juvenile crayfish fall prey to members of the same species and some types of fish, whereas adults are eaten by otters, large fish, raccoons, great blue herons, and minks.

Crayfish face threats from overfishing in some regions, but habitat loss, pollution, invasive species, and disease are also significant threats. Regulations on crayfish harvesting and enforcement vary widely by country and region.

In addition, crayfish are prone to a few infections, such as crayfish plague. Acid rain can also pose a problem. Researchers discovered that entire ecosystems in Canadian lakes troubled by acid rain saw a catastrophic decline in crayfish populations because it weakens their exoskeletons.

Reproduction, Babies, and Lifespan

Male crayfish court females by a sequence of specific movements. First, they will clamp their claws and turn the female onto her back. Then they will deposit the spermatophore into a protective receptacle on the female’s abdomen. Their mating rituals can last from minutes to over an hour.

The number of eggs a female can produce depends on their size. For example, larger females lay more eggs, which have a faster maturity rate. Crawfish females will carry their eggs until they hatch, which usually takes 3 to 8 weeks, depending on the species and temperature. Like many other species, males are not involved in parenting.

Babies

When the hatchlings emerge, they are the carbon copies of their parents but much smaller. Surprisingly, some species of crayfish hatchlings cannot survive without their mothers at first. So, instead, they attach themselves to their mother’s pleopodal setae using specialized hooks on the tips of their legs, where they remain for several weeks.

Female crayfish aren’t that maternal, either. In fact, they have to secrete a form of pheromone, referred to as maternal pheromones, that encourages them to take care of their offspring and prevents them from eating their young. However, these pheromones wear off eventually, and if the juveniles are still with their mother, she won’t waste any time making a meal of them.

Lifespan

Crayfish mature relatively quickly and reach adulthood within 3 to 4 months. Furthermore, depending on the species, they can live as long as 3 to 8 years.

Population

About one-third of crayfish species worldwide are at risk of extinction. In the USA, nearly half of the crayfish species are considered endangered, threatened, or vulnerable.

Different Uses for Crayfish

Humans have 3 different uses for crayfish, and they include:

Food

Cultures all around the world eat crayfish. But, much like other edible crustaceans, people can only eat small portions of their bodies. As a result, many recipes only call for the tail portion, like bisques, soups, and étouffées.

Dishes like crawfish boil are presented with the entire body of the crayfish, but people usually only eat the claw meat. However, one culture that doesn’t eat crustaceans is Jews because crayfish are not aquatic animals and lack fins and scales, meaning they are not kosher.

Bait

Humans aren’t the only species to enjoy crayfish meat; they are also preyed upon by ray-finned fishes and are often used as bait to catch these prized fishes. Therefore, fishermen can use crayfish as live bait or just a portion of their tail meat.

Other fish that respond well to crawfish bait are:

• Catfish
• Largemouth bass
• Smallmouth bass
• Striped bass
• Perch
• Pike
• Muskie

To ensure the crayfish remain active as live bait, fishermen will hook them between the eyes, which pierces through their hard-pointed beak, apparently causing them no harm.

Pets

In some parts of the world, these crustaceans are kept as pets, and pet crayfish come in a variety of shapes, sizes, and personalities. While some crawfish are small, wary, and shy, others are curious, robust, and sometimes destructive.

Crayfish actually make great pets for children or novice owners, as they are relatively easy to care for and do not need a lot of space to thrive. In addition, they are entertaining to watch while active.

Where to Get a Pet Crayfish

There are multiple ways of legally obtaining a pet crayfish. For starters, many exotic pet stores sell them, and they usually have several different species to choose from. In addition, many restaurants have live crayfish in tanks. Of course, you could always ask your waiter if you can buy a live one and take it home.

The most obvious way to get a crayfish is to catch one from a stream, river, or brook. However, ensure there are no restrictions in your area that prohibit the capture of crawfish.

However, no matter where you get them, they will need time to adapt to their new surroundings before they calm down and get comfortable.

Never bring a sick crayfish home; always ensure they are in good health before buying one. If the crayfish are not moving around or appear lethargic, they could have an illness that will decrease their quality of life or even prove fatal. If you have doubts, consult your local aquatic veterinarian to set your mind at ease.

What is the Price of a Pet Crayfish?

Buying a pet crayfish is actually more affordable compared to other pets like hamsters, dogs, or cats. Firstly, setting up the aquarium can cost between $50 and $200, and most pet crayfish cost between $10 and $50, though rare species may be more expensive.

You might think feeding them is expensive, but commercial food costs around $5 to $10 a month. In addition, owners very rarely need to take their crayfish to veterinarians, saving them a small fortune. Lastly, they don’t require toys, but it’s up to the owner if they want to spoil them with additional stimulation.

Are Crayfish an Invasive Species?

Crayfish are considered an invasive species in Europe and China. Unfortunately, they can easily destroy local rice crops.