|Another group of sea cucumbers are scientifically classified as dendrochirote holothurians. Unlike the most typically encountered sea cucumber, which uses its tube-feet for lifting particles of food from the sandy bottom, they remain stationary in position on the reef, using their long, branched feeding tentacles for trapping passing zooplankton from the ocean current. These dendrochirotes are small (about 1 inch tall). The mouth is centered at the base of the five radially positioned tentacles (top), with the anus visible at the lower end. As a tentacle catches a drifting particle, the tentacle retracts inward toward the mouth. Several other sea cucumbers were nearby, partially visible in the lower parts of the photo.|
A third type referred to as an apodus holuthurian is much longer (up to 15 feet) and thinner, with a sticky outer skin and feeding tentacles. Their locomotion is mainly by contraction and expansion of its body.
The spot in the Philippines where I took this photograph is called Mainit Point, near Batangas, Luzon Island (this area is sometimes referenced to a smaller nearby village called Anilao). It is known for strong, unpredictable currents, especially when the tide changes. Mainit Point is the only place I have seen this particular species of sea cucumber-- there were hundreds within a small area of the reef. Another diver visiting the Philippines says he has seen them at Puerto Galera. This is another well-known dive resort area, south of Luzon Island, about an hour ferry ride from Batangas.
(above) Identification: Colochirus robustus