Cancer (genus)

Cancer is a genus of crabs in the family Cancridae. These crabs are found worldwide, predominantly in temperate waters. The genus is characterized by its broad, oval carapace, nine teeth on each side of the anterolateral margin, and relatively large size.

Description

Members of the genus Cancer typically possess a wide, flattened carapace that is roughly oval in shape. The anterolateral margins of the carapace are armed with nine teeth or lobes, which are a key identifying feature. Their claws (chelipeds) are strong and asymmetrical, with one often being larger than the other. The body color varies depending on the species and habitat, but often includes shades of red, brown, and yellow.

Distribution and Habitat

Cancer crabs have a global distribution, with species found in the Atlantic, Pacific, and Indian Oceans. They are particularly abundant in temperate regions. They typically inhabit rocky intertidal zones, subtidal areas, and sometimes deeper waters. They are benthic organisms, meaning they live on the seafloor.

Ecology and Behavior

Cancer crabs are generally opportunistic feeders, consuming a variety of prey, including mollusks, crustaceans, worms, and algae. They are active predators and scavengers. They use their strong claws to crush shells and dismember their prey. Reproduction involves mating, followed by the female carrying the fertilized eggs on her abdomen until they hatch into larvae. The larvae then undergo several developmental stages before metamorphosing into juvenile crabs.

Taxonomy

The genus Cancer is part of the family Cancridae. The taxonomy of the genus has been revised over time, and the exact number of species within Cancer is subject to ongoing research and debate. Some well-known species include Cancer pagurus (Edible crab), Cancer magister (Dungeness crab), and Cancer irroratus (Atlantic rock crab).

Economic Importance

Several species of Cancer crabs are commercially important as food sources. Cancer magister (Dungeness crab) is a particularly valuable fishery species on the west coast of North America, while Cancer pagurus (Edible crab) is a popular seafood in Europe. The crabs are harvested through trapping and other fishing methods.

Conservation Status

The conservation status of Cancer species varies depending on the specific species and location. Some species are subject to fishing pressure and may require careful management to ensure sustainable harvesting. Other species are relatively abundant and not currently considered to be threatened. Monitoring of populations and habitat protection are important for maintaining the health of Cancer crab populations.