I chose to do this interesting specimen today as we saw hundreds of these on our dives this week in Vero Beach and Pepper Park. I mean tons! They were everywhere and some even had shell particles stuck to their bodies like an armor. I do not see many in LDBS or other southern dive shore locations so I am not sure why the sea cucumber is so abundant here. Let’s find out shall we?
First of all, sea cucumbers are echinoderms. There are about 900 species. They are marine animals with a leathery skin and a elongated body that has one single branched gonad. They are found on sea beds around the world. Like all echinoderms they have an endoskeleton just below the skin. They typically range 10 to 30cm in length, however we spotted a much larger one this week. The largest size they grow can be over 3 feet. It is a worm like creature with a spherical body. It does not have arms. The anterior end holds the mouth unlike other echinoderms where the underside usually holds the mouth (like starfish). It could be said that sea cucumbers are laying on their side due to the mouth position. The mouth is surrounded by a ring of tentacles which are generally retracted into the mouth. These are actually modified feet. They are invertabrae and omnivores. Average life span is 5-10 years.
- The largest American species is Holothuria floridana which is prevalent just below low-water mark on the Florida reefs. There are plans to harvest this species for the sea cucumber.
Sea cucumbers found locally are generally scavengers feeding on debris, waste and plankton. Some sea cucumbers will position themselves in currents to catch food as it flows by. They can also sift through the sediment on the bottom of the reef with their tentacles. Sea cucumbers feed on tiny particles like algae, minute aquatic animals, or waste materials, which they gather in with 8 to 30 tube feet that look like tentacles surrounding their mouths. The animals break down these particles into even smaller pieces, which become fodder for bacteria, and then recycle them back into the ocean ecosystem. Earthworms perform a similar function in terrestrial ecosystems. I notice there is always a trail of tube waste behind them when feeding.
Sea cucumbers breathe by pumping sea water in and out of an internal organ called a respiratory tree.
Sea cucumbers have no true brain. A ring of neural tissue surrounds the oral cavity, and sends nerves to the tentacles and the pharynx.
Sea cucumbers have 5 strip like ambulacral areas that run the length of it’s body. Three on the lower surface have many feet that allow it to crawl along. When threatened, some sea cucumbers discharge sticky threads to ensnare their enemies. Others can mutilate their own bodies as a defense mechanism. They violently contract their muscles and jettison some of their internal organs out of their anus. The missing body parts are quickly regenerated.
Most sea cucumbers reproduce by releasing sperm and eggs into the sea. The egg develops into a free-swimming larva after about three days.
Many cultures eat sea cucumber both dried or fresh. They consider it a delicacy. The creature and the food product are commonly known as bêche-de-mer (lit. “sea-spade”). In Indonensia they call it trepang, namako in Japan, balatan in Tagalog and gamat in Malaysia. They are dried for preservation purposes and have to be rehydrated by boiling and soaking in water for several days. They are mainly used as an ingredient in Chinese cuisine soups or stews. In Japan, sea cucumber is also eaten raw, as sashimi or sunomono. The intestine of the sea cucumber is also eaten as ‘konowata’, which is salted and fermented food . The dried ovary of sea cucumber is also eaten, which is called ‘konoko’.
Chinese folk and ancient holistic beliefs attributes male sexual health and aphrodisiac. It is also considered a restorative for tendonitis and arthritis. I think we may be on to something here…how about harvesting this locally, must be a market with all the old people (whoops I mean retirees) that flock here every year.
Some sea cucumber species produce toxins that are of interest to pharmaceutical firms seeking to learn their medical value. Some compounds isolated to date exhibit antimicrobial activity or act as anti-inflammatory agents and anticoagulants.