Use of different bottom substrate types for rearing mud crab crablet (Scylla olivacea) in nurseries

Research Center for Fishery, National Research and Innovation Agency, Cibinong, Bogor, West Java, Indonesia

^* Corresponding author: hjompa@yahoo.com

Abstract

The technology of mud crab hatchery has been successfully implemented, though the survival rate of the larvae, until they reach crablet or juvenile stage, is relatively low. This study focuses on assessing the role of substrates in crablet growth and survival during the nursery. Mud crab crablets with an average initial weight and carapace width of 0.02±0.005 g and 3.43±0.42 mm was stocked into nine fiber tanks with a 30 individual/tank density. A shelter was inserted in the form of 2 black net sheets in each container. The treatment tried was the use of different types of substrates, namely (A) without substrate, (B) sand substrate, and (C) clay substrate. Feeding was done in the morning and afternoon using artificial feed. The results showed that the highest survival was obtained at the treatment without substrate, which was 15.57%, and significantly different (P<0.05) with the treatment of sand substrate and clay substrate. Meanwhile, the highest weight gain was obtained in the clay substrate treatment, which was 1.50g, significantly different from the treatment without substrate and sand substrate. This research demonstrated that the mud crab crablet nursery may be conducted in a container without a substrate if provided with shelter.