Biodiversity #26 – Jellyfish. There are 1,000’s of species of Jellyfish and they are found in all the oceans on earth. Though the English term has been in use since 1794 – they’re not fish, but rather gelatinous zooplankton – free swimming marine animals of the phylum: Cnidaria. (The ‘C’ is silent).
Some amazing and random facts:
Jellies have roamed the seas for at least 500 million years, though most live for fewer than 6 months.
The smallest jellies have a bell about 1 mm across, the biggest up to 2m.
The Australian Blue Bottle (known elsewhere as the Portuguese Man o’ War) is not technically a jelly as it’s a collection of zooids which have different roles, but function collectively as if they were a single animal.
Most jellies have practically no vision, only being able to detect the general direction of light; whereas the box jellyfish as 24 eyes and a 360° view of its environment.
Jellyfish stings range from mild tingling to agony. In the former situation try to wash off any remains of tentacle stuck to the skin with vinegar or salt water; do not rub or use fresh water. In the latter, seek immediate emergency medical assistance. Here’s a useful little post on dealing with Jellyfish stings.
There are groups of jellyfish that have become isolated and have lost their ability to sting. Probably the best known is ‘Jellyfish Lake’ in Palau, where you can snorkel in a lake of non-stinging jellyfish. Watch the movie on this page.
A group of jellyfish is called a Smack. A single jellyfish as is often called ‘Bob’.
Because of their strange method of locomotion, Jellyfish achieve a 48% lower cost of transport (food consumed versus distance travelled) than most other animals. (Or maybe it’s because they work out with their personal trainers as per the video below).