Photographer: Paul Osmond
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This Pacific Cucumber (Bohadschia argus) is displaying several sticky threads which are called Cuvierian Tubules.
Several species of sea cucumbers, all belonging to a single family, possess this peculiar and specialized defense system. It is mobilized when the animal is mechanically stimulated, resulting in the discharge of a few white filaments, the tubules. In seawater, the expelled tubules lengthen considerably and become sticky upon contact with any object. The adhesiveness of their outer epithelium combined with the tensile strength of their collagenous core make Cuvierian tubules very efficient at entangling and immobilizing most potential predators.
Image taken in the Lagoon Reef dive site which is part of the Small Deatched Reef system in far north Queensland in Australia.
Detached Reef's in the area are named as they are near - but not part of - the Great Barrier Reef system.