The squabbling screeches of feeding bats woke me in the dark of 5 a.m., at which time I also heard the wails of bush stone-curlews pealing out into the long mid-May night. An hour later, darkness lifted into the grey light of dawn. I walked toward Bicentennial Park, the bitumen path strewn with pale, pointed ovals of fallen gum leaves beneath my feet. This was a time of voices rather than sightings, of dark wings against dim light, but clear songs – rainbow lorikeet, white-gaped honeyeater, peaceful dove, blue-faced honeyeater.
From Bicentennial Park, Townsville’s downtown towers still glowed with the blue and orange of night lights. The Ross River looked dull, its surface flecked with tiny waves stirred up by wind. Masked lapwings stood like sentinels on a bed of pocked, brown rock extending three-quarters of the way across the river at low tide, with a striated heron patrolling the rock edge beyond them. Fish leapt within the river and pushed dark waves in front of them. Welcome swallows skimmed over the water in acrobatic insect hunts, while nutmeg mannikins foraged for seeds in tall grasses on the bank. When I retraced my steps, I spotted peaceful doves perched on overhead wires and thought they looked unusually scruffy, as though wakened too early into a brightening world.
Marine Stinger Warning on Pallarenda Beach (© Vilis Nams)
Today’s Townsville Bulletin carried stories of murder in the nearby suburb of Oonoonba,1 of Townsville alleged to be the Ku Klux Klan capital of Australia,2 and of stinger nets remaining in place at North Queensland beaches because of the continued presence of box jellyfish in nearshore waters.3
The Queensland coast is, in some ways, a most peculiar place – both beautiful and slightly terrifying. The beaches invite you to walk them, with the proviso that you don’t pick up cone shells, because the snails that live in them can harpoon you, injecting neurotoxin that may kill you.4 You don’t reach blindly into tide pools stranded on rocky shores, because golfball-sized blue-ringed octopus may bite you, and their saliva is drenched with enough neuromuscular paralyzing venom to kill 20 humans within minutes.5 Saltwater crocodiles lurk in estuaries and coastal rivers, camouflaged by duckweed and their ability to submerge for long time periods with only their nostrils protruding. When they strike, as Vilis and I observed at Billabong Sanctuary, they become death disguised as a flashing leap and crushing jaws (see http://maginams.ca//2010/02/20/). Sharks rear their fins in coastal waters,6 and a whole suite of sea snakes glide through coastal waters, powered by flattened, paddle-like tails and packing venom that, in some of the species, can be dangerously toxic to humans.7 And then last – but far from least – we have the stingers, the marine jellyfish with venom-laden stinging cells that possess some of the most potent poisons known to humans.
Marine stingers fall into several medically-important (from the point of view of staying alive or healthy) groups. These are the box jellyfish, the irukandji, the blue bottles or bluies (more familiar to me as Portuguese man-o-wars), and a half-dozen others I learned of for the first time via a Surf Life Saving Queensland poster in the hallway of the School of Marine and Tropical Biology at James Cook University. Since the box jellies and irukandji receive the most media attention (incidents are reported on national radio, like grizzly bear attacks in Canada) and are the most toxic, I’ll deal with them.
Box jellyfish, which are also referred to as sea wasps, have cube-shaped medusae or bells; hence the ‘box’ in the name.8 They are typically pale blue in colour, rendering them almost invisible in the ocean.8 A poster jointly produced by Surf Life Saving Queensland, JCU, and CRC Reef Research Centre showed the species of concern in Queensland waters, Chironex fleckeri and Chiropsalmus, both of which have clusters of tentacles at the corners of their medusae. The former have flat tentacles up to 15 in a cluster, and the latter, round tentacles up to 9 in a cluster. The poster described the tentacles as fettucini versus spaghetti, which creates a visually intriguing picture. As well, the poster pointed out that the box-like medusae of Chiropsalmus are generally smaller than 10 centimeres across, while those of Chironex fleckeri are usually larger than 10 centimetres and may grow as large as 30 centimetres across.
The tentacles of box jellyfish can stretch to 3 metres in length.9 Spaced all along those tentacles are specialized cells called cnidocytes having coiled barbs (called nematocysts) which, on contact with prey react chemically, shoot out from the tentacle, and inject venom into fish, or sometimes into unwary people.8 The venom contains heart, nerve and skin toxins, so victims entangled by tentacles may suffer cardiac arrest or severe shock leading to drowning.9 If victims survive, they experience excruciating pain and terrible scarring due to skin damage and death at the sting site. An antivenin is available for box jellyfish stings,9 but these stingers have been implicated in 64 known deaths in Australia. 8
Only 2 known deaths have been attributed to irukandji stings in Australia.10 These stingers are tiny in comparison with box jellyfish, growing to a diameter of only 1 centimetre and having tentacles from up to 35 centimetres long.10 Whereas box jellyfish possess stinging cells only on their tentacles, irukandji possess them on their bells as well. 10 Two kinds of irukandji occur in Queensland marine waters, Carukia barnesi, which is found in inshore waters, and ‘psuedo-irukandji,’ which is found in offshore waters.11 Both are, like box jellyfish, virtually invisible, and contact with their tentacles causes such intense pain that, in the case of the offshore irukandji, it reaches uncontrollable levels and can lead to cardiac arrest or stroke due to rocketing blood pressure.11 Fortunately, medical intervention in the form of morphine pain control for inshore irukandji stings, and blood pressure medication for offshore irukandji stings has proven effective,11although victims may suffer terrible pain for weeks.10 Now for some good news. Water enthusiasts can purchase lycra suits, known as stinger suits, which offer full-body protection from stingers, but little or none against the other dangerous critters listed above.
Today’s birds: bush stone-curlews, rainbow lorikeets, white-gaped honeyeaters, blue-faced honeyeaters, peaceful doves, masked lapwings, striated heron, magpie-larks, Australian white ibises, brown honeyeater, welcome swallows, nutmeg mannikins, mynas, Australian magpie, rock doves, rainbow bee-eaters.
References:
1. Brooke Baskin. Murder in Oonoonba. Townsville Bulletin, Monday, May 17, 2010. pp. 1,6.
2 Brooke Baskin. Ku Klux Klan claim. Townsville Bulletin, Monday, May 17, 2010. p. 3.
3. Emily MacDonald. Stinger strikes as nets stay in place. Townsville Bulletin, Monday, May 17, 2010. p. 5.
4. this is the Great Barrier Reef. Cone Shells. 2001-2010. Accessed 20-May-2010. http://www.barrierreefaustralia.com/the-great-barrier-reef/coneshells.htm
5. this is the Great Barrier Reef. Dangers on the Reef: Blue Ring Octopus. 2001-2010. Accessed 20-May-2010. http://www.barrierreefaustralia.com/the-great-barrier-reef/blueringedoctopus.htm
6. Townsville Sun. Think twice about swimming in sea. December 30, 2009, p.2.
7. Steve Wilson and Gerry Swan. A Complete Guide to Reptiles of Australia. 2008. New Holland Publishers (Australia) Pty Ltd, Sydney. pp. 474-491.
8.Wikiipedia. Box Jellyfish. Updated 20-May-2010. Accessed 20-May-2010. http://en.wikipedia.org/wiki/Box_jellyfish
9.Birgit Bradtke. Outback Australia Travel Guide. The Australian Box Jellyfish. 2006-2010. Accessed 20-May-2010. http://www.outback-australia-travel-secrets.com/box-jellyfish.html
10. Wikipedia. Irukandji jellyfish . Updated 13-May-2010. Accessed 20-May-2010. http://en.wikipedia.org/wiki/Irukandji_jellyfish
11. Poster. Two groups of Irukandjis! JCU, Surf Life Saving Queensland, Australian Government, Australian Institute of Marine Science, CRC Reef Research Centre, Australian Venom Research Unit, Association of Marine Park Tourism Operators, PPA, Lions International.
