Nursery Performance of Sandfish Holothuria scabra Juveniles in Tidal Earthen Pond Using Different Types of Cage

Abstract

Sandfish Holothuria scabra is a promising aquaculture commodity. Techniques for producing this species have been developed rapidly in recent decades to address the issues of increasing market demand and overexploitation of wild populations. Providing sandfish seed with suitable size for stocking (20-50 g) is one of the main issues in mass production of sandfish. Developing reliable nursery techniques could solve this problem. This study aimed to investigate the survival and growth performance of sandfish juveniles in two types of nursery cage: (i) floating net cages and (ii) fixed net cages. The experiments were conducted in a tidal earthen seawater pond in Sekotong, West Lombok for 14 weeks between August 5 and November 13, 2015. Each type of experimental cage had 3 replicates, stocked with 15 juveniles (mean initial weight 4.22 g) per cage. Feed was provided naturally from the substrate in the pond and in seawater, which was exchanged daily following the natural tidal cycle. Juveniles showed rapid growth and high survival rate for both floating and fixed net cages during the first six weeks of culture with no significant difference (P<0.05). Conversely, at the end of the experiment, the growth and survival of juveniles in the fixed net cage were lower because of the extreme low tide and the dry season, which began after week 6. During the low tide, floating net cages stayed submerged in the water while some parts of the fixed cages were exposed, killing the juveniles attached to the net. Our findings suggest that both cages were suitable for use in sandfish juvenile nurseries, although it is better to use the floating net cage in tidal ponds.