Preliminary Trials on Hatchery and Larval Development of the Sea Cucumber, Holothuria scabra (Jaeger 1883), in the Sultanate of Oman

Abstract

Although sea cucumber Holothuria scabra has always been part of the traditional exploitation of the benthos of Mahout Bay in the Arabian Sea, the foreign demand for the product and its high price have put increased pressure on the resource leading rapidly to overfishing. Aquaculture of this species has developed as a response to the overfishing problem but has not been yet studied in Oman. As a first step to evaluate its potential for aquaculture in Oman it was thus necessary to conduct hatchery trials. Four hatchery trials were conducted to evaluate the quality of the local broodstock, the response and efficiency of in-vitro maturation and fertilization and the success of larval development and rearing. Collected animals of 200-600 g were transported by road for 5 hours with zero evisceration to the Hatchery station. In-vitro maturation and fertilization success of more than 90% were achieved using the maturation inducing fractions (MIF) method leading to the development of mature eggs and normal embryos larvae. Auricularia larval stages were completed within 15 days and fed normally on microalgae Phaeodactylum tricornutum, Chaetoceros sp. and Nanochloropsis sp. Average settlement rate and size for pentactula juveniles were closely to 9% and 0.5 mm, respectively, nearly one month post-fertilization (PF). However, a high mortality of 70% was observed during early larval development caused by ciliated protozoans and copepods attack. The culture of H. scabra population in Oman is thus promising but further research is needed to ensure higher survival rates, particularly in the early larval stages where adequate water filtration and sterilization is essential.