sea jelly time

I recently received an email from a former student – here’s a summary of what Andrew wrote:

"I wonder if you might take a look at the photo of the jelly fish that are currently in the bay (Western Port), there are hundreds of them. Do they sting? Are these the ones that carry the larva of the crayfish back into the bay?"

About the sea jelly (small point - I prefer to call them sea jellies rather than jelly fish) it is Cyanea capillata, commonly known as the Lion's Mane Sea Jelly.

Lion’s Mane Sea Jelly
Cyanea capillata
(click thumbnail for full image)

the Mosaic Sea Jelly
Catostylus mosaicus
(click thumbnail for full image)

In answer to your question about stings - yes this sea jelly can sting humans. The photograph shows one feature of the genus Cyanea, the many fine tentacles that trail underneath the bell.

These fine tentacles give rise to another common name, the Hair Sea Jelly and are loaded with cells (called nematocysts) that the sea jelly uses to sting its pray.

The nematocysts can also cause a moderate to severe sting in humans. This results in painful red marks on the skin and in severe cases may lead to respiratory distress.

In relation to this sea jelly carrying the larva of the crayfish – as far as I am aware, the answer is no. The sea jellies that I have seen carrying the larva of the crayfish back into Port Phillip Bay and Western Port are the Mosaic Sea Jelly Catostylus mosaicus (also known as the Brown Blubber Sea Jelly). These are quite large, up to 350 mm across, bell-shaped sea jellies that should be around fairly soon.