Mälaren, historically referred to as Lake Malar in English, is the third-largest freshwater lake in Sweden. Its area is 1,140 km2 (440 sq mi) and its greatest depth is 64 m. Mälaren spans 120 km (74.6 mi) from east to west. The lake drains, from south-west to north-east, into the Baltic Sea through its natural outlets Norrström and Söderström and through the artificial Södertälje Canal and Hammarbyleden waterway. The easternmost bay of Mälaren, in central Stockholm, is called Riddarfjärden. The lake is located in Svealand and bounded by the provinces of Uppland, Södermanland and Västmanland. The two largest islands in Mälaren are Selaön and Svartsjölandet. Mälaren is low-lying and mostly relatively shallow.
Crayfish are freshwater crustaceans belonging to the infraorder Astacidea, which also contains lobsters. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some species are found in brooks and streams, where fresh water is running, while others thrive in swamps, ditches, and paddy fields. Most crayfish cannot tolerate polluted water, although some species, such as Procambarus clarkii, are hardier. Crayfish feed on animals and plants, either living or decomposing, and detritus.
Cambarus is a large and diverse genus of crayfish from the United States and Canada. The adults range in size from about 5 cm (2.0 in) up to approximately 15 cm (5.9 in).
The signal crayfish is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the North European Astacus astacus fisheries, which were being damaged by crayfish plague, but the imports turned out to be a carrier of that disease. The signal crayfish is now considered an invasive species across Europe, Japan, and California, ousting native species there.
The Parastacidae are the family of freshwater crayfish found in the Southern Hemisphere. The family is a classic Gondwana-distributed taxon, with extant members in South America, Madagascar, Australia, New Zealand, and New Guinea, and extinct taxa also in Antarctica.
Cherax, commonly known as yabby/yabbies in Australia, is the most widespread genus of fully aquatic crayfish in the Southern Hemisphere. Various species of cherax may be found in both still and flowing bodies of freshwater across most of Australia and New Guinea. Together with Euastacus, it is also the largest crayfish genus in the Southern Hemisphere.
Pacifastacus is a genus of crayfish native to western North America, containing six species, two of which are extinct:
The Cambaridae are the largest of the four families of freshwater crayfish, with over 400 species. Most of the species in the family are native to the United States east of the Great Divide and Mexico, but fewer range north to Canada, and south to Guatemala and Honduras. Three live on the island of Cuba. The species in the genus Cambaroides are only found outside North America, as they are restricted to eastern Asia.
Procambarus clarkii, known variously as the red swamp crayfish, Louisiana crawfish or mudbug, is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduced elsewhere, where it is often an invasive pest.
Orconectes is a genus of cave dwelling freshwater crayfish, endemic to suitable habitats in the eastern United States. Surface dwelling species, formerly categorised here, were moved to Faxonius in 2017.
Astacoides is a genus of freshwater crayfish endemic to Madagascar. The first specimens were brought to Europe in 1839, and seven species are now recognised, most of which are considered as threatened on the IUCN Red List. They are large and slow-growing, and are threatened by habitat loss, overexploitation by local people and by spread of introduced non-indigenous marbled crayfish. They are only found in a relatively small part of the island, mostly in undisturbed upland areas. They belong to the Gondwana-distributed family Parastacidae, but their nearest relatives live in Australasia, there being no native crayfish in mainland Africa or India.
Cambarellus is a genus of small freshwater crayfish in the family Cambaridae. The 19 species are found in Mexico and the Gulf States of the United States. Among the Mexican species, C. areolatus, C. patzcuarensis, and C. prolixus are considered seriously threatened by the IUCN, and C. alvarezi is already extinct. C. chihuahuae was also believed to be extinct until rediscovered in 2012. C. alvarezi and four undescribed, extinct Cambarellus species were restricted to desert spring systems in southwestern Nuevo León; each one shared its habitat with a Cyprinodon pupfish.
Procambarus is a genus of crayfish in the family Cambaridae, all native to North and Central America. It includes a number of troglobitic species, and the marbled crayfish (marmorkrebs), which is parthenogenetic. Originally described as a subgenus for four species, it now contains around 161 species.
Horton Holcombe Hobbs Jr. was an American taxonomist and carcinologist, specialising in freshwater decapods. He was also a capable artist, musician, cook and botanist.
Cambarus bartonii is a species of crayfish native to eastern North America, where it is called the common crayfish or Appalachian brook crayfish.
Faxonius limosus, synonym Orconectes limosus, is a species of crayfish in the family Cambaridae. It is native to the east coast of North America, from Quebec to the lower James River, Virginia, but has also been introduced to Europe. It is known commonly as the spinycheek crayfish or Kamberkrebs in German.
Crayfish are eaten all over the world. Like other edible crustaceans, only a small portion of the body of a crayfish is edible. In most prepared dishes, such as soups, bisques and étouffées, only the tail portion is served. At crawfish boils or other meals where the entire body of the crayfish is presented, other portions, such as the claw meat, may be eaten.
Faxonella creaseri is a species of crayfish, a decapod crustacean in the family Cambaridae. It is one of the four species in the genus Faxonella.
