Jellyfish Exposed – They are Blooming Marvellous!

On one of our last Komodo trips of the season, we discovered that two of our guests were leading experts in the world of jellyfish and bioluminescence.  Their humble and friendly natures gave us no clue that they are responsible for theories that are changing the face of evolutionary biology and our understanding of the marine environment.

Siphonophore arist representation

Casey and Steve, who have recently founded Jelly Watch (more below), were generous with their knowledge. They opened our eyes to a whole new world, and we thought we’d share this a little bit further and answer some of those pressing questions about these gelatinous beings!



Wicked: So, the first thing we always get asked, what are the little stingers in the water that I can’t see? Should I be worried about them?

Steve Haddock: It could be a few different things – hydroids that are floating freely in the water column, or possibly siphonophores. They are completely harmless, just a little irritating.

NB: Siphonophores are the transparent floaters in the water column that often form long strings. These strings comprise of many animals living in one colony. The most famous siphonophore is the Portuguese Man-Of-War.

W: Ok, what about the upside down jellyfish? Those guys are crazy!

Casey Dunn: The upside down jellyfish is also called a Cassiopea. It acts like a coral or sea anemone. By using propulsion, it anchors to the substrate; it is not actually physically attached. The whole process allows it to photosynthesize. It pumps water over its frills continuously to aid this.

Upside-down-jellyfish-e1357529327470W: I’ve seen bioluminescence on a night dive before, but what is it?

SH: Bioluminescence can be described as the ability of organisms to make light by chemical reactions in their tissues. Mostly this is not through bacteria, although some more notable and famous species use bacteria, such as the bobtail squid, flashlight fish or pinecone fish.

W: Where can you find it and does it indicate anything special in the water column?

SH: Mainly you would find it in the tropics, both in the deep sea and shallow waters. Bioluminescence can be an indicator of a healthy marine environment. Large quantities may be due to an upwelling from deep water environment.


W: What can be determined by studying jellyfish?



SH: Firstly we can understand their place in the ecosystem and how important balance is in the marine environment. Not only do they compete with creatures such as whales, mantas and other fish for plankton, but they are also an important part of a turtle’s diet. By studying the ecology and biology of jelly fish, we can understand basic things about biology and from an industrial and medical perspective; fluorescence is an important component of many products or treatments.

CD: In addition, we can look from an evolutionary standpoint. Jellyfish have taken just as long to evolve as human and in some cases we can find very direct links to humans. By studying all branches of the animal kingdom, we have a better understanding of the history of all animal life.

W: Is there anything divers can do to help? I’ve heard a lot about Citizen Science…

SH: Well, it’s funny you should mention that. We’ve recently started an initiative called JellyWatch. Jelly Watch is a monitoring programme which allows people from all over the globe to report their jelly sightings directly to us.

Komodo jelly from Steve Haddock

Jellys are very hard to study and it’s very hard for us to quantify numbers and sightings. Eyes are by far the best device, better than satellite or any other instruments. Divers can submit their photos, or even describe their encounters at our JellyWatch website or on our Facebook page.

W: Ok, the question on everyone’s lips….have you ever peed on anyone?

CD: Not because they’ve been stung by a jellyfish (awkward laughter ensues)…just kidding. You’re not going to publish that, right?

In seriousness, it is always best to opt for vinegar, or in the case of the Portuguese Man-Of-War, hot water.

Steve Haddock is a marine biologist who is interested in all of the fragile organisms which reside in our oceans, their diversity and how they make light. 

Casey Dunn is an evolutionary biologist who wants to learn more about all animals by studying jellyfish.