Development of methods for mass rearing of tropical sea cucumbers for the purpose of enhancing wild stocks

• Ministry of Agriculture and Fisheries, Solomon Islands
• James Cook University, Australia
• James Cook University, Australia

Sea Cucumbers are a valuable source of income for coastal communities in the Indo-Pacific. However, increasing demand has caused an over-exploitation of many stocks, particularly high-value species. Management of stocks is difficult because of the remote and artisinal nature of fishery. The ability to sustain or increase the yield of sea cucumbers by "enhancing" wild stocks is a potentially valuable tool for managers. Sea cucumbers appear suitable for enhancement because they are restricted to inshore habitats, are low on the food chain and are easy to harvest. Fisheries for temperate sea cucumbers have been enhanced for many years in Japan. There are also reports from India and Indonesia indicating that tropical species can be bred and farmed. The research will concentrate on sea cucumbers of high value that are relatively abundant in the Solomon Islands.

The project forms the first part of a long-term research program to propagate and release sea cucumbers, evaluate the survival, and assess the impact of releases. The objective of the project is to develop techniques for mass rearing of juveniles of tropical sea cucumbers. The specific aims are: 1) To develop reliable methods for inducing sea cucumbers to spawn, 2) To provide an abundant supply of suitable live algae for the nutrition of sea cucumber larvae, 3) To develop repeatable, cost-effective methods for rearing the larvae and juveniles of sea cucumbers to the stage where they are robust enough for transfer to coral reef habitats.

The first year of the project was dedicated to the establishment of facilities and recruitment of staff. Discussions between ACIAR and ICLARM representatives in February 1996 resulted in agreement to establish an Advisory Panel to provide advice on larval rearing during the first phase of the project. During the second year the algal unit and hatchery facilities at the CAC were completed. The algal unit now produces seven species of algae in sufficient quantities to meet hatchery needs. Experiments to determine how best to collect and transport sea cucumber broodstock and induce them to spawn were also carried out. Spawning and larval rearing of two batches of sandfish was successfully undertaken, and two other species were partially reared. Finally, development of methods for detaching juvenile sandfish from rearing tanks and growing them in concrete tanks on artificial diets was being achieved.