Juvenile red swamp crayfish growth affected by isolation from their mother

The red swamp crayfish (Procambarus clarkii Girard, 1852) which is indigenous to North America, is the most commercially exploited species in astaciculture. Farming profitability depends mainly on crayfish growth rates. Thus research focused on factors affecting growth of crayfish is of high priority in this sector of aquaculture. Growth rate retardation related to social deprivation in crayfish has never been evaluated in crustaceans. The present experiment was carried out in order to compare growth rates of the Stage 3 juvenile red swamp crayfish from two offspring origins: maternal incubation and early separation from the mother. Juveniles were kept in three types of groups composed each by six individual: maternal incubated, early separated, and mix of both of them. Offspring origin significantly affected juvenile crayfish growth rates when maternally incubated individuals grew faster than crayfish from the other two group types. Moreover, the same significant differences were shown in number of moults. The results of the present study provide new insight into crayfish behaviour related to prior social experience of juveniles, but future studies are needed to verify our assumption.