Patricia Holden MD|

I’ve been writing (or should that be typing?) about another jellyfish post earlier when my daughter came up to me and mentioned how beautiful they are. Having been stung by jellyfish before, the memory of the incident actually caused me to view them in a different way. However, thanks to my daughter’s comment, I became open to the idea of simply listing a few of the more beautiful jellyfishes I’ve seen.

Aequorea Victoria - A bioluminescent jellyfish. They are commonly found in Puget Sound, Washington State. Adult Aequorea victoria reach about 5 to 10 cm in diameter and live to around 6 months or less. They feed primarily on soft-bodied prey including other jellyfishes, ctenophores, and appendicularians. The luminescent protein and their fluorescent molecule have been cloned by scientists to produce a similar effect in other plants and animals.

Aurelia Aurita - Also called the moon jellyfish or saucer jellyfish. Simply look at the picture and you would see how it got its nickname. They can be found in the Atlantic, Pacific, and Arctic Ocean and are the most common species of the genus Aurelia. It is only capable of limited motion and drifts along with the current. It feeds by stinging small plankton and mollusks with its tentacles and then bringing them to the body for digestion by contracting its tentacles in a corkscrew like manner. It is considered as food in countries such as China, Philippines, Thailand, Malaysia, and Indonesia.

Chironex fleckeri - Known for its highly venomous sting, the box jellyfish Chironex fleckeri is one of the most dangerous jellyfish around. It is said that it can kill 60 adult humans in as little as 3 minutes. It is is the largest of the cubozoans, and is pale blue in color. What makes it extremely dangerous is it’s color which makes it virtually undetectable by swimmers. The only creature known to be immune to their stings are their predators - sea turtles. They can be found mostly near northern Australia and sometimes near Southeast Asia.

Chrysaora colorata - Also called the purple-striped jelly. It can be found mostly off the coast of California. Its body, known for the radial pattern of its stripes, can grow to around 70 centimeters in diameter. Even though it is not shown in the picture, it has 8 long tentacles and 4 shorter ones at the center.

Pelagia noctiluca - Also known as Mauve Stingers. Its name, Pelagia noctiluca was formed from the Greek words Pelagia meaning “of the sea”, nocti meaning “night”, and luca meaning “light” - in other words, its name refers to a sea creature that lights up in the dark. It can be found in warm temperate waters like the Mediterranean sea but there have also been sightings near Hawaii. According to one report back in November 21, 2007: an enormous 10-square mile swarm of billions of these jellyfish wiped out a 100,000-fish salmon farm in Northern Ireland. These days, mauve stingers are treated as a menace by mediteranean resort owners. Read about it here.

I was thinking of a follow-up post about jellyfish or jellyfish stings until I encountered this article about the growth of jellyfish population in oceans and how it is an indication that something has changed and how it poses as a threat to marine ecosystems. Usually, when someone mentions “species population” and “environmental degradation” we immediately think of words such as “pollution”, “global warming”, and “endangered species”. However, changes in the environment and ecosystems, or environmental degradation is not only hinted by a decline in a certain species’ population. A drastic increase or sightings of a certain species in one area (where it is uncommon) could also mean the same thing.

Phytoplanktons - I’m sure a lot of you have heard of this one, particularly in Ecology class. Anyway, phytoplanktons are best known to be one of the reasons for eutrophication (increase in primary productivity in lakes resulting in lack of oxygen needed by fishes to survive) in lakes and rivers. Eutrophication promotes excessive plant growth and decay and is likely to cause severe reductions in water quality. Enhanced growth of choking aquatic vegetation or phytoplankton disrupts the normal function of the marine ecosystem, causing a variety of problems. You won’t be able to see phytoplanktons directly, but a good sign of high density of their species in a body of water would be the water’s color itself. A bright green color would indicate that there are a lot of phytoplanktons in the water.

Crabs and other Crustaceans - 40 million years ago when the waters in the polar regions froze and lowered the temperature of the water around them, crabs and other marine predators were driven away. Now, with global warming becoming an issue and the temperature level of the waters around the poles increasing, those same predators are going back and would most likely be feeding on the defenseless marine creatures in their new territory. This would throw the ecosystem out of whack and would have a great impact on species diversity.

Jellyfish - Now for the article itself. According to Jacqueline Goy of the Oceanographic Institute of Paris, “Jellyfish are an excellent bellwether for the environment”. Why? This was answered by Ricardo Aguilar, the research director for Oceana, an international conservation organization. According to him, “Jellyfish have come to occupy the place of many other species; when vertebrates, such as fish, disappear, then invertebrates - especially jellyfish - appear. The collapse of fish populations boost this process in two important ways, he added. When predators such as tuna, sharks, and turtles vanish, not only do fewer jellyfish get eaten, they have less competition for food.” This not only poses a threat on the direct environment but also on humans as well. Just imagine encountering an army of those things while swimming. You’ll be covered in jellyfish stings and that would most likely prove fatal.