Reproduction of astacid crayfish in captivity—current developments and implications for culture, with special reference to Ireland and Spain

Summary Astacid crayfishes, native to western Eurasia and western North America, are iteroparous and long-lived (6–12 years), reaching final sizes of about 30–500 g and 90–200 mm total length, depending on species. While economically valuable, their low fecundity and slow growth makes economic aquaculture difficult. In Spain and Ireland the relatively small native white-clawed crayfish Austropotamobius pallipes (Lereboullet) carries around 70 eggs for 8–9 months and reaches first maturity at 3–4 years and 50 mm total length. The larger signal crayfish Pacifastacus leniusculus Dana, introduced to Europe from California, matures at about 70 mm and 2 years and carries some 200 eggs for 8 months. A. pallipes alone occurs in Ireland; both species in Spain. We have investigated fecundity, oviposition and subsequent egg development of diese species in field and laboratory and developed strategies to maximize egg survival in artificial incubators. Temperature manipulations may be used to maximize juvenile survival and also to modify incubation period. For successful aquaculture critical phases in captivity are mating and fertilization, pleopodal egg attachment, late embryo survival and moult from Stage 1 hatchlings to free-living Stage 2 juveniles.