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Jan. 17, 2012

Australia: Where Even the Seashells Can Kill You

by Kaitlyn Gerber

Click to enlarge images

By Kaitlyn Gerber, Carleton College

The deadly (but beautiful) cone shell.

The other day, we attended a lecture called "Toxic and Venomous Marine Organisms." (Or something along the lines of "things that can kill you." You get the drift.) I learned something very important: Australia has many, many creatures that can kill the unsuspecting traveler. Don't get me wrong -- this is a wonderful country, and I love it here. But since we're doing fieldwork here, with a future emphasis on snorkeling, it pays to be careful. So, if you're curious, here are a few of the things I've learned about surviving in Australia -- and a few of the creatures that I'll be watching out for (aside for sharks and crocodiles, of course).

First of all, it's important to distinguish between "venomous" and "poisonous." A venomous organism is an organism that secrets or injects venom from glands or tissues, creating a wound. However, poisonous creatures do not actively inject other animals - they are simply harmful when ingested. In other words, they have poison within them, but they have to be eaten for it to do any damage. For example, a jellyfish is venomous because it can actively sting its prey, but a monarch butterfly is poisonous because it can only harm a predator if it is ingested.

That being said, here are a few of the creatures I'll be watching out for:

Jellyfish: The most venomous marine animal on Earth, the box jellyfish, is native to Australia's northeastern coast. Fortunately, I'm too far south (currently) to run into them, but their venom is among the most potent of any creature in the world. Also called the Sea Wasp, the box jellyfish

The deadly Box Jellyfish (C. Fleckeri)

has tentacles that can grow up to 3 meters long, are covered in stinging cells (called cnidocytes), and, upon contact, release a neurotoxin that attacks the central nervous system and can cause paralysis, shock, and cardiac arrest. Being stung by a box jellyfish is extremely painful, and can be fatal.

On the other hand, the jellyfish we do have to worry about here are Bluebottles, commonly known in the States as the Portuguese Man o' War. The Bluebottle actually isn't a true jellyfish; instead, it is actually a colony of minute individuals. Approximately 10,000 Bluebottle stings are reported annually in Australia, including a few that have already happened on this trip (I have yet to run into any of these though -- fingers crossed). Their stings are painful, but fortunately not fatal.

Mollusks: Believe it or not, octopi and squids are actually mollusks, and Australia is home to one of the deadliest - the Blue-Ringed Octopus, known by the distinctive blue rings that appear on its skin when it is startled or frightened. Although it is only slightly larger than a golf ball, the Blue-Ringed Octopus contains tetrodoxin, a neurotoxic venom that is 10,000 times more lethal than cyanide, and can cause immediate difficulty swallowing, blurred vision, numbness, and eventual respiratory arrest. Usually victims have trouble signaling for help because paralysis sets in, but CPR can often help keep a person alive until medical help arrives. These octopi are found at our current island, so I'll have to be extraordinarily careful while snorkeling.

In addition, the phylum Mollusca also includes the"seashell" I mentioned in my title -- it's actually a predatory snail called the Coneshell. These snails live mainly in mudflats and shallow reef waters, and contain teeth that can pierce skin like small harpoons. Their shells are often colorful, which entices people to pick them up. Unfortunately, their "teeth" actually contain a paralytic neurotoxin, which can cause either spastic or flaccid paralysis. A bite from a Coneshell should be treated immediately with a pressure bandage and emergency medical care. Since I really don't want my parents to have to tell people their daughter was killed by a poisonous seashell (that, and I'd rather not die...), I'm being especially careful not to pick up any strange shells while I'm here.

Fish: The Reef Stonefish is a carnivorous fish that disguises itself as a rock so that it can live on reef bottoms. Like several other Australian creatures, they are extremely venomous -- in fact, their venom makes them the most toxic fish in the world. They have thirteen spines along their back, which contain myotoxins capable of causing intense pain and affecting skeletal and cardiac muscle. Stonefish also aren't aggressive; rather, most people are affected by stonefish venom after accidentally stepping on one.

Snakes: Australia is home to six of the top ten deadliest snakes in the world, including the deadly inland taipan, which has the most toxic venom out of any species in the world. However, the taipan causes significantly fewer deaths than other Australian snakes. The main snake we've been told to watch out for is actually the brown snake, the second most venomous land snake that can also be aggressive when provoked. Its venom can cause dizziness, nausea, and even paralysis and cardiac arrest. Fortunately, their initial defense tends to be non-fatal bites, so the mortality rate from bites is relatively low.

We're almost done our research here on North Stradbroke Island, and pretty soon we'll be in Lamington Plateau, so I'll do my best to update when I can. Happy January!

A few of us watching the sunset the other night. Photo credit: Ned Heckman, Carleton College '13.

____________________________

Kaitlyn Gerber is a sophomore at Carleton College, where she plans to major in biology. Originally from Ridgefield, CT, she is an active soccer player and science fan, especially of ecology and astronomy.

About Kaitlyn Gerber

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