Induction of Spawning in the Sea Cucumber Holothuria scabra (Echinodermata: Holothuroidea)

Authors


Corresponding author's present address: School of Environmental and Marine Science, University of Auckland, Leigh Marine Laboratory, PO. Box 349 Warkworth, New Zealand.

Abstract

With the advent of sea cucumber aquaculture in the South Pacific region, a reliable method is needed to induce large numbers of animals to spawn in captivity. Broodstock of the sea cucumber Holothuria scabra, collected from Stradbroke Island, Moreton Bay (27°90′N, 153°24′E) Australia, during the reproductive season from October to January, were used in spawning trials. During the 1997–1998 summer between one to five weeks of captivity, 100% of animals were induced to spawn in four trials at dusk on or close to a new or full moon, using nine males and nine females contained in a Reln tank and 30 cm of filtered sea water, using a 3–5 C temperature shock. H. scabra was induced to spawn in small numbers during the 1996–1997 summer despite a marked degree of weight loss, and all animals spawned during 1997–1998 with minimal loss of weight. The difference in the number of spawned eggs between animals of similar size and mean numbers of spawned eggs in consecutive trials decreased the longer animals were held in captivity before spawning. The hatch rate of eggs was reduced significantly for broodstock held for more than one month. Hatch rate and numbers of spawned eggs are important indicators of egg viability of broodstock maintained in captivity for an extended period.

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