Optimal first feed organism for South African mud crab Scylla serrata (Forskal) larvae

It is not known whether rotifers or Artemia nauplii are the best first food for South African mud crab Scylla serrata larvae. In order to test this, larvae were fed with five different test diets. These were rotifers for the first 8 days and newly hatched EG(R) type Artemia nauplii ( San Francisco Bay) from day 6 onwards ( treatment R6A); newly hatched EG(R) type Artemia nauplii throughout the rearing period ( treatment EG); newly hatched Vinh-Chau strain ( Vietnam) Artemia nauplii throughout the rearing period ( treatment VC); decapsulated cysts of EG(R) type Artemia throughout the rearing period ( treatment DECAP); or decapsulated cysts supplemented with low densities of Artemia EG type Artemia nauplii ( treatment MIX). Two experiments were conducted approximately 1 month apart using larvae from two different female crabs. Although results showed it is possible to rear S. serrata larvae through metamorphosis on Artemia nauplii exclusively, larval performance ( development, survival and successful metamorphosis) was enhanced by the inclusion of rotifers as a first feed. No significant difference in performance was recorded between larvae fed on the two strains of Artemia nauplii. Larvae fed on decapsulated cysts in treatments DECAP and MIX performed poorly, but there were indications that decapsulated cysts and other inert diets may have potential as supplements to live food in the rearing of S. serrata larvae.