Breeding and growth of the burrowing prawn Calhanassa kraussi stebbing (Crustacea: Decapoda: Thalassinidea)

Abstract

1. C. kraussi in the Swartkops river estuary in South Africa has a major breeding period in winter-spring (May-July/August) and a minor breeding period in summer (November-January).

2. A maximum of 43 per cent of ovigerous mature females was recorded. Females in the 8 and 9 mm carapace-size classes make the major contribution to the breeding effort.

3. Recruitment is very marked with 60-80 per cent of the population consisting of juveniles at times.

4. Both sexes live for about two years. Females hatching in winter-spring may breed first in summer at an age of about 16-18 months and then again in the following winter at an age of about two years. Females hatching in summer breed first in winter at an age of about 18 months and some in the following summer at an age of about two years.

5. Breeding and growth in C. kraussi is compared with that in other known callianassids, and discussed in relation to estuarine eco-systems and conservation measures.