INTRODUCTION
North America is second to no other land mass in its freshwater crayfish fauna. It includes two families, Astacidae and Cambaridae, 12 genera, Pacifastacus (Astacidae) and Barbicambarus, Bouchardina, Cambarus, Cambarellus, Distocambarus, Fallicambarus, Faxonella, Hobbseus, Orconectes, Procambarus, and Troglocambarus (Cambaridae), and well over 300 species (Hobbs 1988). The bulk of the species belong to the family Cambaridae and are naturally distributed east of the great western mountains that divide the continent. However, one Orconectes species has naturally crossed that barrier and two other aggressive, large species, Orconectes virilis and Procambarus clarkii, have been successfully introduced (Bouchard 1978; Hobbs et al. 1989). The genus Pacifastacus is the only representative of the family Astacidae in North America. Native to the west coast from British Columbia well into California, at least one representative of the genus, P. leniusculus, is a large, aggressive species that has been widely introduced within the region but has yet to be moved eastward within the continent.
The commercially important crayfish species in North America include, in order of significance, the red swamp crayfish, Procambarus clarkii, the white river crayfish complex, Procambarus spp.,1 the signal crayfish, Pacifastacus leniusculus, the rusty crayfish, Orconectes rusticus, the papershell crayfish, Orconectes immunis, and the fantail, or northern crayfish, Orconectes virilis (Huner 1989c). Other species are harvested when they are locally abundant and some invade fish culture systems. In addition, there are so many other species that more species are sure to be eventually involved in some form of exploitation, either through harvesting of wild populations and/or culture. Most likely candidates will be tertiary burrowers of the genus Procambarus, subgenera (Ortmanicus) and (Scapulicambarus), and larger Orconectes spp.
The most important single crayfish species is P. clarkii which accounts for 70-80% of all crayfish harvested in North America, natural fisheries and culture combined (Huner 1989c). It is cultivated along with white river crayfish throughout the southern and southeastern USA. The state of Louisiana dominates the industry with 50,000 ha of earthen ponds (Sandifer 1988). Information about production in the USA is presented in Table 1. The other important cultured species is O. immunis. No survey data are available about culture of this species but pond area devoted to its culture probably approaches 500 ha in states bordering the Great Lakes between Canada and the USA. Reference to its intentional culture for fish bait dates from the early 1940s (Tack 1941). This species was largely considered to be too small for food markets but closer examination has demonstrated that, under the proper conditions, it can be cultivated to much larger sizes (McCartney and Garrett 1989).
The North American crayfishes range in size from the tiny dwarf species of the genus Cambarellus, which rarely exceed 1 g to the large members of the genera Cambarus, Orconectes, Pacifastacus, and Procambarus which can, under suitable conditions, achieve sizes of 50–80 g. Growth is rapid compared to that observed in European species because climate is much milder. Maturation and reproduction can be realized in one year throughout the continent although this often requires two years at higher latitudes (Payne 1978; Momot 1984).
North American crayfishes have long been used as food, fish bait, specimen for specific research and teaching, pets, and objects of social significance (Huner and Barr 1991). They were first exploited by the continent’s original aboriginal inhabitants and later by the multitude of ethnic groups who came later. The first records of crayfish culture date from the late 1700s when Louisiana plantation owners sometimes raised them in small ponds for the family’s kitchen (Comeaux 1975). While larger species are preferred for food, even the dwarf crayfishes were and still are collected for food in Mexico. These are eaten whole as a part of taco fillings.
Intentional commercial crayfish culture seems to date from the 1930s and 1940s with references to their culture for fish bait and food appearing in the literature then (Langlois 1935; Viosca 1937; Tack 1941). Crayfish culture for fish bait developed in the Great Lakes states largely as an adjunct to regular finfish cultural endeavors (Huner 1978a). Crayfish culture for food developed principally in the state of Louisiana as an adjunct to the rice industry there (Viosca 1966). However, no determined effort has been made by the Louisiana industry to pursue fish bait markets (Huner 1988b).
Table 1. Crayfish Production (Tons) in the U.S.A. (1990).
| Region | Wild | Aquaculture | Species |
| Southern | 5,000–25,000 | 60,000 (65,000 ha) | Procambarus clarkii |
| | | P zonangulus* |
| | | P. a. acutus* |
| | | Procambarus sp.* |
| Northcentral | 100 | 150 (500 ha?) | P clarkii Procambana sp.* |
| | | Orconectes immunis |
| | | O. nisticus |
| | | O. virilis |
| | | Orconectes spp. |
| Northeastern | ? | 25 | O. immunis |
| | | Orconectes spp. |
| Western | 300–500 | none | Pacifastacus leniusculus |
| | | P clarkii |
* These three species were previously considered to be one species Procambarus acutus acutus.
Both forms of crayfish culture share common origins in that crayfish invaded existing fish culture ponds and rice fields. While it is feasible to cultivate crayfish from egg to egg within closed systems, no one has yet been able to make such an endeavor financially successful (Huner 1990d). Soft-shell crayfish are produced profitably in tanks and pools but only by harvesting the animals from earthen ponds where they have been grown in extensive culture to a suitable size before transfer to tanks and pools.
BASIC LIFE CYCLE CONSIDERATIONS
North American crayfishes are, as stated earlier, cultivated by establishing sustaining populations in earthen ponds. These ponds are invariably dried intentionally for crayfish management purposes or for fish husbandry purposes with the crayfishes surviving in burrows. Therefore, it is important to understand basic life cycles. (This discussion will be limited to cambarid crayfishes. The life cycles of astacid crayfishes are covered in the European section of this book.)
One North American astacid species, P. leniusculus, has been widely distributed throughout western Europe and young are cultivated for establishing sustaining populations in semi-controlled pond units which are not drained (Westman et al. 1990). Astacid crayfishes cannot persist in burrows in dry ponds because they are not physiologically able to l...
