Holothuria impatiens Breeding Guide

How the burrowing sea cucumber Holothuria impatiens reproduces once a year by broadcast spawning into planktonic larvae, why it is not home-bred, and its defensive Cuvierian tubules.

Overview

Holothuria impatiens, the tiger-tail or burrowing sea cucumber, grows to about 15 cm with leathery skin mottled brown, grey or purplish-brown and banded in alternating pale and dark colours. It is a nocturnal, very cryptic deposit feeder that sifts sediment with its feeding tentacles and ingests dead biological material such as seaweed fragments. Its range spans the tropical Indo-Pacific, western Atlantic, Caribbean and Mediterranean at depths of about 2 to 40 m.

Reproductive Mode

The species is gonochoric and reproduces sexually by broadcast spawning, casting gametes into the water; reproduction takes place once a year, in late spring or early summer on the Great Barrier Reef. Females produce a small number of large eggs.

Asexual Reproduction

Although several related sea cucumbers reproduce asexually by transverse fission, H. impatiens has never been observed to do this. Population increase in this species therefore depends entirely on its annual sexual spawning.

Sexual Reproduction

Broadcast fertilisation produces planktonic larvae. As in sea cucumbers generally, development passes through the ciliated auricularia and barrel-shaped doliolaria stages before the juvenile form is reached, requiring weeks to months of suspended planktonic feeding.

Common Challenges

The planktonic larval phase cannot be supported in a display aquarium, so the species is not propagated at home. When handled, H. impatiens readily expels sticky Cuvierian tubules as a defence, and like other holothurians a dead or severely stressed specimen can foul the water.