Tubular sea cucumber

Holothuria (Holothuria) tubulosa is a species of purple-green echinoderm, with an elongated cylindrical shape. It lives a sedentary or semi-sedentary lifestyle, most often on rocky, sandy and muddy seabeds. The soft spines that are visible on the surface of the body, called aquatic legs, help the sea cucumber to move. It has two cavities at the top of the body, the oral and the anal. Aqueous feet in the oral cavity play a role in feeding. With them, the sea cucumber collects organic material from the seabed or plankton from the water column. In case of danger and attack by predators, they have the ability to excrete entrails from the oral cavity (evisceration) or poison through the skin. It reproduces sexually by external fertilization with male and female gametes. In summer, during the mating season, both sexes have the tendency to raise two-thirds of their bodies in an upright position and release the gametes into the water column. The fish Carapus acus, also known as longtail, often finds shelter in the anal cavity of a sea cucumber in case of danger.