Today we are going to talk about american crab. It is a red crab that is from the river and originally from the United States, hence its name. It can be seen on other continents where it is mostly known as an invasive species. In our country it is known as the American crab and we also have it in our habitats.
In this article we're going to give you all the details about the Biology, characteristics and life forms of the American crab, its expansion, potential impacts, and management and care considerations where its ownership is legal.
Key features
It is a type of crab that lives in waters that are not very coldThis means that it lives in rivers, but generally in calm waters. It is considered one of the species with the greatest adaptability It thrives in different ecosystems. It grows quite quickly in seasonal waters and can withstand the hottest and driest times of the year for up to 4 months. In terms of dimensions, it measures 12 centimeters in length and weighs about 50 grams. only.
This crab not only lives in freshwater, but we can also find it in waters with a certain degree of salinityBecause they don't tolerate these waters well, they don't stay in them for long. Their lifespan extends to at least 5 years if conditions are fairly good. They feed on both plants and other animals.
In its juvenile phase it presents a lighter pigmentation, whitish-yellowish; with maturity, the shell acquires a intense reddish toneThe body is elongated and robust, with a narrow rostrum and tuberculate pincers. As a decapod, it possesses 10 legsthe two front ones being the large clamps or cleats. sexual maturity It usually reaches around intermediate sizes, and its growth depends on the frequency of molting of the exoskeleton.
Its environmental tolerance is broad: the acceptable temperature range encompasses temperate waters, with a optimal activity between moderate temperaturesIt also tolerates low oxygen Thanks to its habit of coming to the surface or into damp soil and its ability to dig burrows, it can walk on damp ground. long distance to find new bodies of water, which favors their expansion.
Taxonomy, origin and distribution
The American crab or Procambarus clarkii belongs to the family CambaridaeIt is native to the southern United States and some areas of northern Mexico, but has been introduced to Europe, Africa and Asia. In the Iberian Peninsula has successfully established itselfoccupying numerous rivers, reservoirs, marshes, and rice paddies. Its ecological plasticity, natural dispersal over land during wet periods, and human activity (translocations, historical trade, fishing) have facilitated its expansion.
In many European rivers its presence is stable, but its advance has been especially pronounced in warm-temperate regions, where displaces native crabs less tolerant of habitat alteration and already pathogenic. In our territory it is considered invasive alien species and is subject to strict control measures and prohibitions regarding its introduction, transport and trade, in accordance with current regulations.
Habitat and ecology
Habitat occupation: it is found in slow-moving riversmarshes, ponds, pools, reservoirs and, notably, rice paddiesIt prefers soft bottoms with silt or clay, where excavates galleries to find shelter, reproduce, and withstand seasonal droughts. During dry periods, it can remain buried for several months until the water returns.
Environmental parameters: tolerates wide temperature ranges and low to moderate salinity. The temperate average temperature range favors their metabolism and reproduction, and the dissolved oxygen Low pH does not prevent its survival if it has access to the surface or damp burrows. Regarding pH, it shows a preference for waters with low pH. neutral to slightly alkaline.
Ecological role: as opportunistic omnivore and scavenger, consumes macrophytes, algae, detritus, invertebrates, amphibians in early stages, eggs de peces and small fish. This broad diet allows it to persist where other species fail. Its burrowing activity makes it a ecosystem engineeraltering the habitat structure and sediment dynamics.
American crab care
This type of crab can be kept as a pet. To have it at home you must know some of the main guidelines of its care so that it is healthy at all times. They eat a lot of fruit, vegetables, and different types of meat. So that they can drink water, you need to place a sponge with water and they will absorb as much water as possible. From time to time, it is convenient to soak them in fresh water and that is at room temperature to improve their conditions.
The great thing about the American crayfish is that it can tolerate water temperatures of varying levels, from hot to cold. If you're going to keep one at home, you'll need a terrarium And you can make a kind of cave for them with leaves and sticks, so they can go in whenever they want and feel totally protected.
To differentiate between male and female crabs, you have to look at the size of the claws. On the one hand, to know which is the male, you can see that one of the clamps is larger than the other. But nevertheless, the females have the two claws of the same size. If you want to make a habitat that is comfortable for them, you will need a fish tank or terrarium. It should be something large so that you have plenty of room to move around.
You can buy a container to place its cave in the corner, and also have another corner covered with water where it can go into it. Place plants there as if the crab were in its natural habitat. You can also buy it a trunk and place it near its habitat. That way you can make a hole at the bottom so it can dig out soil and get inside.
Next to the water container you can place a food cap so that things can be closer together and not everything is scattered. The more sand I have, it is better so that the crab can feel in its natural habitat. If you add plants and decorate everything as close to a natural habitat, the better. And it is that these crabs, although they adapt easily to new environments, always do better if these environments are fully adapted to the natural part.
Essential legal consideration: In various countries, including Spain, the American crab is classified as an invasive alien speciesTheir possession, transport, and trade are prohibited by law. If you live in a place where their domestic use is legal, apply the following technical recommendations:
- Safe installation: aquarium with a tight-fitting lid; they are excellent climbers and escape artists.
- Water parameters: warm and stable temperature; neutral to slightly alkaline pH; good filtration and oxygenation.
- Decoration and shelters: hollow logs, caves, and tubes for hide during moltingAvoid sharp objects.
- Compatibility: Avoid bottom-dwelling or slow-swimming fish; they may prey on them or nip at their fins. Keep them alone or with robust species in separate areas.
- Feeding: Sinking pellets for crustaceans, blanched vegetables (zucchini, spinach), occasional lean protein. Remove any leftovers to avoid polluting the water.
- Maintenance: regular partial changes, never use products with copperDisinfect equipment if it has been used outdoors to prevent the spread of pathogens.
- Preventive measures: dissemination and surveillance of invasive species to avoid translocationscleaning and UV-C disinfection. of arts and vessels used in different bodies of water.
American crab diet
These fish can feed on both plants and animals. Within the animals it feeds on both invertebrate animals and other fish. Vegetables are also eaten in large quantities. You can observe a tendency to cannibalism or more pulling at carrion. And we can see an American crab eating another of its own species, as long as this specimen is dead or dying. It can also be seen eating some carcasses of other species if there is little food available.
The fact that it is part scavenger makes it a key piece in cleaning general of all ecosystems. To differentiate it from other crabs, one only needs to look at its more elongated morphology. This shape makes them similar to lobsters and, like all other crabs, they possess the ability to molt the exoskeleton.
In natural environments it consumes macrophytes, filamentous algae, seeds, snails, aquatic insect larvae, developing amphibians and eggs de peces when they are available. This opportunistic diet This explains its invasive success, but also its potential to disrupt food chains, increasing water turbidity by uprooting vegetation and stirring up sediments as it searches for food.
In captivity, where legal, it is advisable to ration food in little portions Feed daily or every other day, prioritizing sinking foods specifically formulated for crustaceans and blanched vegetables. Avoid excess protein to prevent accelerating problematic molts, and remove uneaten food after a few hours to avoid polluting the water.
Reproduction
We are going to talk about the reproduction process of the American crab. This is one of the questions that many people ask when seeing this morphology of crabs. There are many questions that are asked about how both the male and the female do the sexual act. The answer is pretty straightforward. The male, in order to copulate with the female, has to be larger, since they have to hold the female and position her belly down.
In order to carry out the pregnancy, the males locate the sperm of the females. Inside it, the sperm are capable of holding out for many days until the right time comes for the female to be in her fertile days. The female can lay 700 eggs, but it only depends on the size of both the male and the female. Once it has laid the eggs, they can have about 20-30 days until the moment of hatching.
Under favorable conditions, females can reproduce several times a yearwith cycles associated with temperate periods. After hatching, the young remain attached to the pleopods They remain with their mother until they complete a couple of molts, at which point they are able to fend for themselves. Sexual maturity is reached quickly in waters with good temperature and abundant food, which accelerates their colonization.
Populations with highly efficient reproductive strategies have been observed, including high juvenile survival rates in warm environments and a fertility linked to size of the females. This combination of multiple clutches, rapid development, and broad environmental tolerance explains its remarkable success as an invasive species.
Behavior
These crabs are quite good at communicating with each other. It is one of the best inter-species communications. To be able to talk to each other, they move the clamps a lot, which makes it quite a hilarious act. When you see that an American crab is moving its claws, it is communicating with another of the same species.
Another characteristic it possesses in its behavior is that They work quite well as a team. They both search for food and help support families. They are good swimmers and swim from side to side.
In addition, the American crab is primarily crepuscular and nocturnalIt is most active at dusk. It can swim by propelling itself with its tail. flow fan and move laterally with agility. It burrows for shelter and to stabilize its microhabitat. In competitive situations, it shows territorial behaviors with deployment of pincers.
When threatened, it adopts defensive postures with raised claws or flees abruptly. It possesses a remarkable capacity to limb regeneration after several molts, which allows it to recover from conflicts or partial predation.
Interactions between species and predators
As a broad-spectrum omnivore with few effective competitors in many ecosystems, the American crayfish shares habitat with native fish and introduced species. Among its regular predators Carp and other large fish are mentioned, as well as waterfowl such as herons. In river systems where it is present, some eel-like Native species may prey on it occasionally. Opportunistic mammals (rodents, dogs) and various birds may capture individuals on banks and in shallow areas.
The combination of high fecundity, dietary plasticity, and burrow shelter It makes it difficult for natural predation to control their populationsespecially in modified waters or with abundant emergent vegetation.
Impacts and invasion: effects and regulations
The American crab can generate ecological and economic impactsIn aquatic environments, their galleries destabilize slopes, dikes, and banks, favoring leaks and breaksBy removing sediments and consuming macrophytes, it increases the water turbidity and alters submerged plant communities, with effects on habitat quality and phytoplankton.
As a healthy vector of pathogens of native crabs (for example, crayfish plague), it can cause collapses of native populations. In agroecosystems, it damages irrigation systems and rice paddies due to its excavation activity. Because of these impacts, it is included in the Spanish Catalog of Invasive Alien Specieswith prohibitions on its possession, transport, and trade, and with authorizations for its control for management purposes. It is essential to review the current regulations in your region before any interaction with the species.
Control and prevention methods
Effective management combines methods physical and preventative adapted to the system:
- Targeted capture: nets, traps, manual fishing or selective capture techniques where authorized.
- Physical control in infrastructure: Slope reinforcement, anti-intrusion barriers in canals and gates.
- Preventive measures: disclosure and to avoid translocationscleaning and UV-C disinfection. of arts and vessels used in different bodies of water.
- Habitat management: Reduction of artificial shelters and control of excessive vegetation where appropriate, always under environmental criteria.
The key is to avoid its unintentional dispersal and minimize conditions that favor its population explosion, relying on initiatives of local science to halt its advanceAny program must be coordinated with environmental authorities.
Differentiation from native crabs and similar species
In areas where they coexist, it can be confused with native crayfishThe American crab is notable for its reddish coloration In adults, robust chelae with evident tubercles and a shell with reddish-white dottedNative specimens tend to have browner or greener tones and less prominent structures. If in doubt, it is recommended do not manipulate the fauna and contact environmental agents for identification.
I hope this information helps you learn more about the American crayfish and its characteristics. Understanding its biology and behavior helps identify it, understand why it adapts so well to so many ecosystems, and make responsible decisions regarding its management where legal and its control in the wild. A combination of environmental tolerances, omnivorous diet, efficient reproduction, and burrowing ability explains its success, while also underscoring the need for... prevention and management to protect native habitats and species.
