Preliminary study on broodstock rearing, induced breeding and grow-out culture of the sea cucumber Holothuria scabra in Sri Lanka

Abstract

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Experiments were conducted to identify suitable methods for broodstock rearing, induced breeding and grow-out culture of Holothuria scabra in Sri Lanka. Two hundred and seventy-two brooders (500-600 g) collected from off Mannar were individually packed in oxygen-filled polythene bags with and without sea water and transported to a sea cucumber hatchery at Kalpitiya. Lagoon pens, sand-filled fibreglass tanks and bare tanks were used in triplicates to maintain brooders. Spawning was initiated using air dry, water jet and thermalstimulation methods. Hatchery produced juveniles with an average weight of 11 ± 5 g were reared (2 individuals m~2) in lagoon pens, mud ponds and fibreglass tanks in triplicates. The significantly high evisceration rate was observed when brooders were transported without sea water (t-test, P < 0.05). Brooders maintained in bare tanks showed a significant weight reduction than the brooders in sandfilled tanks and lagoon pens (anova, P < 0.05, d.f. = 2). Thermal stimulation (ambient temperature ± 3-5°C) was found to be the most successful method of spawning initiation of H. scabra. The mean (±SD) percentage males and females participated for spawning per trial was 9.2 (±10) and 4.6 (±5.6) respectively. On an average, 1.16 millions of eggs (±1.03 SD, n = 5) were obtained per spawning trial. H. scabra juveniles reared in tanks showed significantly lower growth rate than the juveniles in pens and ponds (anova, P < 0.05). Lagoon pens and sand-filled tanks are suitable to maintain brooders and lagoon pens can be successfully used for mass rearing of juveniles