Sea cucumbers may vaguely look like their namesake but these marine creatures are far more interesting than any land vegetable could hope to be. A delicious delicacy, a cure for cancer, an important decomposer, and all around strange looking animal – the sea cucumber is certainly an interesting marine creature. Belonging to the class Holothuroidea, sea cucumbers are also echinoderms and thus related to sea urchins and starfish. However, different from other echinoderms, these soft bodied holothurians stand out from the crowd for several reasons.
The Vast Array of Sea Cucumber Species
There are over 1400 different species of sea cucumber in the ocean, coming in a variety of sizes, colors, and lifestyles. According to the entry “Holothuroidea” at the Tree of Life Web Project, sea cucumbers can range from less than a centimeter to 5 meters long. The average size for an adult sea cucumber is about 30 centimeters.
Sea cucumbers are most diverse on shallow tropical coral reefs, but can be found throughout the world’s oceans from inter-tidal zones to the deepest trenches thousands of meters below the sea. Although many species live on the ocean floor, according to the Tree of Life, they can also live planktonic lives floating with the ocean’s currents. Further, several sea cucumber species have the ability to swim.
Sea Cucumbers and the Economy
Sea cucumbers are economically important as a cuisine item and as a source for new pharmaceuticals. This squishy marine creature is considered a delicacy by many, particularly people in Japan and China. In 2001 over 7299 tonnes of sea cucumber were imported globally for $56.7 million according to the UN Food and Agriculture Organization in “World Markets and Trade Flows of Sea Cucumber/Beche-de-mer”.
Perhaps more interesting however, are the compounds within sea cucumbers that can be used to create new disease-curing drugs. These sea animals have long been used in Asian medicine to treat wounds, arthritis, and impotence. However modern medicine is now studying the sea cucumber for cancer medications. According to the American Cancer Society on their “Sea Cucumber” page, sea cucumber compounds have shown some promise in slowing the growth of cancer cells. Although more research is needed, the sea cucumber has proved to be worthy of study.
Why Sea Cucumbers Throw Away Their Guts
Sea cucumbers are also of interest because of their unique defense mechanisms. According to Chicago’s Shedd Aquarium page “Explore by Animal -> Sea Cucumbers”, these ocean creatures can produce a toxic mucus as a defense, or secrete a substance so sticky a razor is needed to scrape it off the skin. Perhaps the sea cucumber’s most interesting defense mechanism however is its ability to self-eviscerate. In particularly stressful times a sea cucumber can eject its guts – confusing its predator and giving it time to run away.
However, according to Peter Fankboner of Canada’s Simon Fraser University, some sea cucumbers eject their guts seasonally. In his paper “Seasonal visceral atrophy and response to salinity by Parastichopus californicus”, some sea cucumbers eject their guts every year in order to get rid of parasites and parasite damaged organs. The sea cucumber has a unique metabolic system that allows it to live while it grows new organs.
Ecological Importance of Sea Cucumbers
The sea cucumber is also of great importance ecologically. Most sea cucumbers are detritus eaters. Detritus includes dead animals, plants, and fecal matter – all of which can be found decaying in the dirt of the ocean floor. A sea cucumber can use its tentacles to scoop dirt into its mouth, where it then swallows mud and sand digesting what it can and excreting what it can’t. In this way sea cucumbers act as decomposers – breaking down materials into nutrients so they can be reused in the ecosystem. According to “The International Wildlife Encyclopedia” by Maurice Burton and Robert Burton, studies show that one acre of coral reef can may contain 2000 sea cucumbers, passing 54 tonnes of sand through their bodies each year.
Megan Jungwi - Megan Jungwi started her freelance writing career in March 2009. Although new to online writing Megan has long been passionate about the ...
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