3. Dangers in the nearshore
Here are some examples of marine animals that you should be aware of and take precautions against disturbing. This is not a complete list and you should research your own area.
1. Dinoflagellates in Red Tides
These single-celled organisms are not visible to the naked eye, but can accumulate in the mollusks, crabs, and fish that eat them. Paralytic shellfish poisons (PSPs) from dinoflagellates are not affected by heat and maintain their toxicity even after cooking. Another possible danger is breathing in dinoflagellates through sea spray, this is a concern when near high-density “blooms,” commonly known as "red tides." Symptoms from inhaling toxic dinoflagellates include running noses, coughing without phlegm, and asthma-like conditions.[2] For healthy people, these symptoms usually disappear quickly, especially in air-conditioned environments. If you do see a red tide, try to avoid the spray or wear a mask. People with asthma or respiratory illness should watch from afar.
Photo Source: Discovery Channel, Canada. Exn.ca[1]
2. Sponges
Though sponges are animals, they form sessile colonies that filter seawater for food. Sponges come in many shapes and sizes, with many small openings for water to flow. Quite a few sponges are poisonous, producing slimy substances that cause skin irritation and inflammation. Sponges to avoid include the fire sponge Tedania ignis and Neofibularia nolitangere in the West Indies and North America, the red sponge Microciona prolifera in the northeastern United States, and Neofibularia mordens andNeofibularia irata in Australia.[3] You often feel nothing when you first touch a poisonous sponge. A burning, stinging, or itching feeling begins hours, or even days, after initial contact. Washing your hands immediately upon touching a sponge does not prevent these symptoms. Other complications include stiffness in nearby joints, reddened skin, swelling, and blisters. If the toxin touched the eye, inflammation of the iris and corneal damage may occur. Microscopic needle-like spicules from sponges that lodge in your skin will also cause irritation. You can remove these glassy spines with fine forceps and washing with soap and fresh water. Soaking in cold water eases the pain, and doctors may prescribe a steroid cream for the affected skin. (Photo Tedania ignis Source: Wetmedia.com[4])
3. Jellies and Sea Anemones
Jellies and sea anemone tentacles contain nematocysts, stinging cells with barbs that are coiled until discharged. Contact with those tentacles will produce immediate pain. Jelly tentacles can leave whip-shaped imprints of inflamed skin. Undischarged nematocysts can lurk on even dry surfaces for a long time, only to sting upon accidental contact.
Translucent jellies may be hard to spot, even in clear waters. Close-weave clothing, such as intact pantyhose, can protect against stings. Diving headfirst in waters without protective clothing is risky, especially during the late summer months of areas known to have jellies.
If stung, you should avoid rubbing the affected skin. Nematocysts are not discharged all at once; touching them can increase the dose of venom you receive. Vinegar, when poured in large amounts for at least 30 seconds, can prevent further discharge of the nematocysts. This method will not neutralize the venom that is already in your skin and will not work for certain species.[3] Another common treatment is the application of unseasoned meat tenderizer mixed with water for up to twenty minutes to end the pain. If jellyfish tentacles cling to your skin, remove them immediately after treatment with vinegar. As a last resort, you can pick them off with your fingers, which have thicker keratin which will give you some protection from the pain. Ice or cold packs can alleviate the sting. Pain from sea anemone stings can be delayed from 30 to 60 minutes, after which the skin quickly reddens and swells. First aid treatment is similar to that of jelly stings.
4. Corals
Some corals contain nematocysts, while hard corals like the Acropora often yield cuts or abrasions. Though they may appear to be minor, you should treat coral cuts immediately. Pressure on the wound will control any bleeding, but you should scrub the affected area with a soft bristle brush and fresh water even if it seems to initially cause more irritation. Aside from venom, the wound may also contain coral polyps and other organisms that will cause infection.
Photo: Hard Corals, NaGISA
5. Sea Stars and Sea Urchins
A few sea star species, such as the crown-of-thorns sea star Acanthaster planci in the Indo-Pacific, have venoms on their spines.[5] Some spines can even penetrate wetsuits. Symptoms include severe pain, bleeding, redness, swelling, and numbness. If you are "pierced," pull out spine fragments immediately, stop the bleeding by applying pressure, and seek medical attention. Hot water can relieve some of the local pain.[3]
Solid spines from sea urchins can puncture your skin and break off in it. Some sea urchins, however, are also venomous. The needle-spine sea urchin Diadema setosum is found in shallow waters in the Indo-Pacific as far north as Japan.[6] Its thin spines contain toxins. The flower sea urchin Toxopneustes pileolus, on the other hand, has thin stalks supporting disc-shaped pedicellariae. The Toxopneustes pileolus is one of the mostvenomous sea urchins, but venom comes from the pedicellariae, not the small white spines. Contact with your skin can lead to numbness and even respiratory difficulties.[7]
Puncture wounds from a sea urchin spine result in immediate pain. As spines break off easily, you can remove them with care. Pedicellariae, however, continue injecting venom even when pulled from the sea urchin. You should remove them quickly with something other than your bare hands. Keeping the affected area immersed in hot water will inactivate some of the toxins.[8]
Photo: Eel, NaGISA
6.Others
Depending on where you are there will be specific things to look out for but in general always be careful for animals trying to protect themselves or their homes. Keep a watchful eye out for heads popping out of crevices (example eels whose teeth can take take off a finger) or lurking under overhangs. In General try and resist the urge to "touch" but be exceptionally careful with elaborately ornamental or colourful animals (such as the lionfish, whose share spines can inflict a lot of pain) take there beauty as a warning from Mother Nature to be cautious!
Photo: Lionfish, NaGISA
[1] Brahm Rosensweig. "Blooming menace of the seas." Discovery Channel Canada.
[2] "Neurotoxic Shellfish Poisoning." Lora E. Fleming, NIEHS Marine and Freshwater Biomedical Sciences Center.
[3] Venomous and poisonous marine animals. A medical and biological handbook. JA Williamson, PJ Fenner, JW Burnett, JF Rifkin ed. Sydney: University of New South Wales Press, 1996
[5] Kosarek, N. 2000. "Acanthaster planci" (On-line), Animal Diversity Web.
[6]Gangaze. (In Japanese) 串本海中図鑑．Ministry of the Environment. Japan.
[7]Rappa-uni. (In Japanese ) 串本海中図鑑．Ministry of the Environment. Japan.
[8] Gallagher, Scott. "Echinoderm Envenomations." eMedicine.