
About
A holothurian - Holothuria tubulosa, the common sea cucumber. In the photo it's in its characteristic upright feeding stance. Sea urchins are visible nearby too - the classic rocky-sandy seabed of Mesimvria.
Echinoderms have no arms, and the two surviving classes of this subphylum today are sea urchins and sea cucumbers.
What it does
It's the vacuum cleaner of the seabed.
They generally feed on waste in the ocean's benthic zone. Their diet includes dead and decomposing organic matter found in the sea, in the seabed mud. Sea cucumbers swallow the entire seabed mud, filter it, and expel it clean again.
That's why their blood is yellow in colour.
Without them, the seabed would be smothered in organic sludge. A single sea cucumber filters kilos of sand a year.
Is it dangerous?
No. It doesn't bite or sting. If disturbed enough, it may release sticky white threads (Cuvierian tubules) as a defence. Don't pull it, don't take it out of the water. Just leave it standing where it is.
It's also protected in many areas - collecting it for food or export is prohibited.
Seabed & Snorkelling
- Shore: Sand with pebble
- Seabed: Mixed, sand with rocks - that's where it lives
- Water: Spotlessly clear, which is exactly why it lives there
- Snorkelling: Yes, completely harmless to observe up close























































