Natural growth and reproduction in Triops granarius (Lucas) (Crustacea: Notostraca)

Abstract

Field sampling during successive inundations was followed by laboratory studies on growth, egg production and hatching of Triops granarius from temporary pans in southern Africa.

The species was common where mean inundation was less than one month. Sexual maturity was reached in as little as six days at a carapace length of 6.5 mm. A biomass of 2.0 g, at carapace length of 25 mm was achieved in two months. Males and females occurred in similar numbers and mating was a prerequisite for sustained fertile egg production. Eggs were in similar numbers in both pouches, while successive clutches were larger. Hatching was light-dependent. Desiccation of eggs was not necessary but a period of up to 20 days was required before undesiccated eggs would hatch. In the event of desiccation, no minimum period thereof was necessary and hatching occurred within as little as a day of rehydration. Hatching success seldom exceeded 50 percent.

As a candidate for aquaculture, the species has failings such as low hatching rate and cannibalism, but it grows rapidly and produces eggs over an extended period.