Effect of nursery site on the growth performance of juvenile sea cucumber, Holothuria scabra, in earth pond-based hapa systems

Abstract

The tropical sea cucumber, Holothuria scabra, plays an important economic and ecological role. Aquaculture of this species has been developing rapidly, and an increasingly effective and efficient system for juvenile production is required. Nursery is a crucial process, as it involves the transition of rearing methods from indoor hatcheries to outdoor environments. This study determined the influence of various nursery sites within earthen pond systems on the growth and survival of juvenile H. scabra. Juvenile H. scabra with a mean wet weight of 1 g (n = 50) were held in replicate floating hapa units over 84 days across four nursery sites: reservoir pond (RP), stirred pond (SP), non-stirred pond (NSP), and main inlet sluice (MIS). Sea cucumbers in MIS exhibited significantly higher weight gain (6.95 ± 0.90 g), growth rate (0.08 ± 0.01 g day⁻¹), and specific growth rate (2.36 ± 0.15% day⁻¹) than all other treatments. Survival did not differ significantly among treatments, ranging from 64.00% ± 2.37% to 74.80% ± 5.82%. The MIS exhibited the highest growth rate for juvenile H. scabra, presumably supported by favorable environmental conditions and effective water exchange. These findings highlight the importance of water circulation and nursery site selection indicating that strategically positioning hapa units close to inlet zones may improve juvenile performance in commercial aquaculture.