The new carapace forms underneath, where it takes a number of days to harden. Rusty crayfish mate in late summer, early fall or early spring.  The four pairs of well-developed walking legs are used for most movement, but the pleopods are small and no use for swimming; when alarmed, koura can flick their tails forward violently to propel themselves backwards at speed. This is not particularly surprising, given the high abundance that northern crayfish achieve. planifrons. The Northern Clearwater Crayfish, Orconectes propinquus (Girard 1852)  is ubiquitous in North America ranging from southern Ontario and Quebec, as far south as southern Illinois, Indiana, Ohio, Pennsylvania, and New York, and as far west as Iowa and Minnesota [13,14]. Faxonius virilis can be found under stones and logs in lakes, streams, and wetlands, where they hide from predators, such as fish. Paranephrops is a genus of freshwater crayfish found only in New Zealand. Plastic containers, tyres, plastic piping, and bottles are all possible habits for koura to occupy when being grown in ponds. Tweet; Description: Crawdad pulled to shore with a Kastmaster while Trout fishing at Camden State Park on the Redwood River. Orconectes propinquus A number of environmental challenges exist for koura farmers in ensuring optimum growth and survivability of stock. The Northern Clearwater Crayfish is found in a variety of habitats (Berrill, 1978). During daytime, they find shelter under rocks, debris such as cans and bottles, and vegetation. Survival of koura also increases with higher calcium concentrations in the water, and this is thought to be in part due to a lower incidence of moulting-related deaths and decreased risk from predation. Males transfer sperm to the females, but external fertilization does not occur until the water temperature increases. Datum: 24. While wild Pacific salmon is abundant, wild Atlantic salmon is so rare that you'll probably have to catch it yourself. Faxonius virilis is a species of crayfish known as the virile crayfish, northern crayfish, eastern crayfish, and lesser known as the lake crayfish or common crawfish. Feeding in the littoral zone may reflect diel movement with koura moving to deeper and darker parts of lakes to avoid predation during daylight hours and moving to the littoral zone at night to feed. This enables the tail to be presented as an appealing white flesh to the consumer.. Greater activity by koura increases cannibalistic behavior, and increased activity may also affect water quality with the greater production of ammonia as a waste product. Females were significantly more abundant than. Their first pair of legs (chelipeds) are pincers used for scavenging food and warding off predators or other koura. Export of koura to the international market may offer less potential due to competition from other established freshwater crayfish species such as the red swamp crayfish Procambarus clarkii, of which the United States and China annually consume 34,000 tonnes and 88,000 tonnes, respectively. Former genus, Orconectes, is from Orcus, god of the underworld in Roman mythology + nectes: swimming (Greek); propinquus: nearby (unclear what this is in relation to) This parasite causes degeneration of striated muscle in the tail area, which turns the tail a pale white colour and correspondingly leads to death soon after. Once hatched, juvenile koura cling to their mother's abdomen using their pincers to attach until they have reached a length of 4–10 mm (0.16–0.39 in). ), whitebait (Galaxias spp. Juvenile koura can be consumed whole by larger koura, and this presents problems for aquaculture in ensuring continuity of intergenerational growth. Other terrestrial predators include rats, kingfishers, shags, scaup, stoats, and kiwi.  Overstocking of crayfish can lead to higher rates of mortality, which is associated with higher rates of cannibalism and increased competition for shelter and food. In soft sediments they may also excavate burrows or fan shaped depressions, in Lake Rotoiti at depths of 5–10 metres (16–33 ft). The complex farms the North Island species (Paranephrops planifrons) of New Zealand's Native freshwater crayfish marketed by New Zealand Clearwater Crayfish (Koura) Ltd (NZCC) and farmed under Ormond Aquaculture Ltd (OAL) freshwater fish farm permit FW76. Northern Clearwater Crayfish Faxonius propinquus Description of the Northern Clearwater Crayfish Etymology: Faxonius, named for Walter Faxon (1848-1920), American ornithologist and carcinologist. Koura is sold solely to the high-end restaurant trade, where they are commonly eaten as an entrée dish. 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