Dangerous Animals of the Great Barrier Reef :: Ecology Nature Zoology Essays

Dangerous Animals of the Great Barrier Reef According to Dennis Fulkerson, one of the Australia Explorers (1996), the Great Barrier Reef is "God's underwater playground." Indeed, everyone in the group seemed to have a fabulous time exploring the reef. However, many of the group expressed some amount of fear about snorkelling on the reef, far away from the mainland. I began to wonder if there was really that much to be afraid of. We were only told that it was not box jellyfish season, and, more importantly, not to touch anything. According to Ryan (p 167), "In general, animals of the reef are benign; only a hungry shark or a mentally defective barracuda is likely to attack unprovoked." Nevertheless, there are a few creatures of which to be aware. Sea snakes, jellyfish, and certain varieties of sea urchins, coral, worms, starfish, mollusks, and fish possess defense and/or feeding mechanisms which can render them harmful if handled by humans. Bristle Worms Bristle worms possess numerous razor-sharp calcium carbonate bristles (setae) which the animal may raise if threatened. These bristles penetrate the skin easily and cause intense itching and sometimes infections. Bristles should be removed with forceps and a local anesthetic and ointment may be applied. The worm may also bite (Ryan, p 170). Sea Urchins Sea urchins, along with heart urchins and sand dollars, belong to the class Echinoidea, which is in the phylum Echinodermata. Echinoids possess numerous spines, which are used for locomotion and defense, and pedicellariae, tiny, pincer-like structures which are used in feeding. The spines, interestingly, consist of a single crystal of calcium carbonate "that would be as brittle as chalk if not for certain glycoproteins in it" (Harris, p 718). Some urchins have venomous spines which can cause severe pain. For example, according to Lutz (p 679), "Some sea urchins, especially those living on coral reefs, have hollow spines that contain a poison; the pacific Asthenoma has needle-sharp spines that can easily penetrate the skin, break off, and release a poison that is extremely painful and dangerous to humans." The flower urchin, Toxopneustes pileolus, (Figure 1) has poisonous pedicellariae which can potentially kill a human. Toxic material can also be contained in the layer of skin coveri ng the spines, so injection of a spine itself is enough to cause intense pain (Endean, p256). As for treatment, Ryan (p170) recommends removing all spines from affected area with forceps, as long as this can be accomplished without breaking the spine and thus releasing more of the poison.