Sea Cucumbers

Kingdom	Animalia
Phylum	Echinodermata
Class	Holothuroidea
Order	Aspidochirotida

Family	Stichopidae
Genus and Species	Parastichopus Californicus
Family	Cucumaridae
Genus and Species	Cucumaria Miniata
Family	Sclerodactylida
Genus and Species	Eupentacta Quinquesemita

General Characteristics

The shape of the sea cucumber is an elongate cyclinder with a mouth and anus on oppsite sides. It has a worm like body that layes parallel to the ocean's floor. The external surface of the sea cucumber is very soft because it is an invertebrate (without a spine), it also has five rows of tube feet that are all along the length of their body. Around the mouth there can be more than ten ambulacral appendages, branched, oral tenticles, and ambulacral feet that can be on all sides.
The internal structure of sea cucumbers consists of an alimentary canal, which is a long tube that runs from the mouth of the sea cucumber at the forward end to the anus which is at the posterior end of the sea cucumber. The posterior end of the sea cucumber is enlarged and becomes narrower towards the anterior end. There are two types of respiratory organs, they are the respiratory tree and the cuvier's organ. These organs function as a pair to pump water through the system. The body wall of the cucumber consists of powerful longitudial muscles runing along the radii, and travers mucles in the interradi.

Reproduction

Sea cucumbers reproduce with organs consisting of a single branch (called a gonad) that opens to the ouside of the dorsal surface either within the ring of oral tendrils or back to it. This gonad is probably homologous to the axial organ of other echinoderms. Sea Cucumbers usually have seperate sexes, however certain hermaphrodites do occur. Several species carry the eggs and young in pouches. Cucumbers, like all other echinoderms, have great regenerative powers. They are able to rengerate lost parts, and certain species can break themselves in two by transfer division, each half becoming a new animal. In most species, the young are hatched in the body cavity, where they undergo development, ultimately emerging through a rupture of the body wall.

Distrubution and Habitats

The sea cucumbers are found in most oceans and in all depths. Some move over the bottom of the sea, some swallow sand and or mud and others catch small organisms. Most of the sea cucumbers live near rocks, corals or sea weeds. Although most of the sea cucumbers live among the sea grasses some do live in the mud or in the sand.

Predators

The ocean is one big food chain, and the Sea cucumbers are both predator and prey in this complicated cycle. However, the principal predators for sea cucumbers are sea stars and fish. Various species have different methods of protections. The most interesting method is the ability of Sea Cucumbers to eviscerate (or expel) their organs. This distracts their predator and enables them to swim to freedom. Other methods of protection includes curling up and rolling away, living in groups (safety in numbers) in hope that their neighbour will be eaten and not them, and the main meathod is simply hiding. Also, one tropical variety eject sticky tubules to repel predators.

Economical Uses and Biological Signifigance

What most people don't know is that sea cucumbers can be eaten just like those in our refrigerators. Although it is not common to eat them here in B.C., Sea Cucumbers are used in many Asian dishes from the far East and are even considered delicacies! Sea cucumbers are also eaten by the first nations on the B.C. coast. The many varieties and species of Sea Cucumbers around the world are an essential part of the ecosystem of the ocean. They are both predators and prey to many different organisms. Their main food source is plankon (incredibly small drifting organisms in the sea,) they also provide food for certain Sea Stars. Because they are a living animal, they are part of the ecosystem and will become a food source one way or another. As mentioned previously, the most fascinating characteristic of the sea cucumber is their ability to eviscerate their guts, thus providing food for their predators while still being able to survive themselves. The ability to provide food for other organisms labels the Sea Cucumber as a provider (of food)in their marine environement. As all other marine creatures, it is essential to protect both the Sea Cucumbers themselves, and their environment to ensure the continueing survival of diversity in the oceans.

Parastichopus Californicus

Common Name: California Sea Cucumber
The P. Californicus can be identified by their prominent, stiff, conical papillae (cone-shaped spines). They also have tube feet on their ventral side. They are dark red or brown in color and have an approximate length of 40 cm (16 inches). They are found on the Northwest coastal waters from Alaska to Isal Cedros in Baja, California. They live in an subtidal habitat, as well as feeding on detritus and small organisms. They are currently the only Sea Cucumber harvested in British Columbia, however only every three years to control population decline. They are eaten for their five muscle strips and body wall. One California Sea cucumber is shown below, this one is currently being kept at the Bamfield Marine Station and we have nick named him "Mike."

Cucumaria Miniata

Common Name: Burrowing Sea Cucumber
This bright orange sea cucumber has ten branched tentacles and five rows of tube feet. They are 25 cm (10 inches) long and live along the western coast from Gulf of Alaska to Avila Beach in California. They live in rocky areas with lots of crevices to hide from their predators, particulary the Sea Star Solaster Stimpsonii. They live in the intertidal zone all the way out 24 m (80 ft) or so. Their branched tentacles are used to collect drifting food. The photograph below shows a Burrowing Sea Cucumber, along with sea grass, it's favorite environement.

Eupentacta Quinquesemita

Common Name: White Sea Cucumber
These Sea Cucumbers can not completely contract their tube feet. They have ten yellow or white branched tentacles, eight long and two short. They are ten cm (four inches) in length and live both off the coast of japan, as well as the Sacramento Reff, Baja, California. They like rocky places, from lower intertidal to 15m off shore. Their tentacles remain retracted during daylight hours. A White Sea cucumber is shown below, lying on a rocky surface.