The sea cucumber is closely related to sea stars and sea urchins, as it possesses the same five part radial symmetry, though not quite as obviously. Sea cucumbers are very slow moving, and can modulate the body to change size or shape. These animals can range in color, but are commonly found in shades of red, black, blue, green or brown. With a life span of about five to ten years, the sea cucumber does not have a brain and has a ring of tentacles around the mouth. Growing to be anywhere from .1 inches to three feet in length, the average size is about three to 12 inches. These nocturnal animals live in colonies and are considered benthic, meaning living life on the sea floor.
Sea cucumbers feed on organic matter amongst the sand by using a filter method. With a sweeping motion, sand and sediment is taken into the body with feeding appendages. All organic matter is digested, while any remnants are excreted in strands or piles back to the sand again. One sea cucumber can filter up to 99 pounds of sediment in just a year! The sea cucumber breathes through the anus, as water is drawn through the body and expelled again, after reaching an organ called respiratory trees where oxygen is extracted. The most fascinating detail of the sea cucumber has to be the methods of avoiding predators. The animal can eject all internal organs through the anus as a distraction to flee from danger, or can expel a toxic white grouping of threads called Cuvierian tubules that will both shock and entangle any hungry predators. If the sea cucumber expels internal organs, it can take months to regenerate and the ability to eat is lost until healing is complete.
Spawning for sea cucumbers typically occurs in large events during a high tide or a full moon. Members of the species will gather together amongst the ocean floor and emit a milky game through pores located near the mouth. After the eggs and sperm have been expelled into the water and fertilized, the spawn will go from a planktonic stage to a larvae stage, before finally settling onto the sea bed.
Of the 1,200 species of sea cucumbers across the world, about 50 can be found amongst the islands of Hawaii. Millions of these creatures are exported to Asia each year as a source for food and medicine, and due to a decline in population, in January 2016 harvesting was heavily restricted in Hawaii.
While the sea cucumber may not be the most beautiful of sea creatures in the Maui waters, it sure is a sight to see! Snorkelers of the island can find these animals sprawled across the ocean floor, and also amongst the displays at the Maui Ocean Center! Go Rent A Car Maui has vans, trucks, suv’s and sedans ready for ocean adventures or even a trip to the Maui Ocean Center to see these tube feet covered sausages of the sea!