Spines and Stingers: Which Ocean Critters to Avoid

We’re all fascinated by the vast array of creatures living beneath ocean waves. Biological diversity ranges wide there, from flora and creatures we know well to the almost alien-like life forms deep in the depths. Who knows what incredible marine life is waiting to be discovered in the more than 80% of ocean that is unmapped?


What we do know is some marine life doesn’t take kindly to human encounters. We are promptly bitten, stung, or speared as a warning to get out of their personal space. You’re more likely to encounter critters with stingers or spines during ocean athletic activities than the biters. While it’s never pleasant to be on the receiving end of those defenses, there are definitely specific stingers and spines you’ll want to avoid at all costs. As in deadly. Or extremely painful.


We recently wrote about the top jellyfish you never want to meet. They certainly qualify for stinging critters to avoid! But some of the top stinging or spiny ocean critters to avoid aren’t even jellyfish at all. Here are a few:


Portuguese Man O’ War

Figure 1https://commons.wikimedia.org/wiki/File:Physalia_physalis,_Tayrona_national_park,_Colombia.jpg


It is a popular misconception that the Man O’ War is a jellyfish. It’s not! It is a type of siphonophore, which is a colonial organism made up of many smaller units: medusoid and polypoid zooids. Together they act as one. You’ll want to avoid these “floating terrors” in tropical and subtropical waters where they live near the surface. The stinging, venomous tentacles can paralyze fish and cause extreme pain in humans. The Man O’ War sting can even kill humans in some cases.


Electric Eel

Figure 2https://commons.wikimedia.org/wiki/File:Electric-eel.jpg


The electric eel has a fascinating reputation popular in myth and tall tales. And just as the Man O’ War is not a jellyfish, the electric eel is not an eel! It is a type of knifefish. Knifefish have long bodies and undulate through the water to swim. The electric eel lives in South America and can grow to over six feet in length. They can generate low voltage or high voltage electric organ charges. Their electric abilities can actually control the nervous system of their prey, and they have been known to leap from the water to attack. Electric eel shocks can be ten times the power of a taser, with larger eels able to deliver potentially lethal shocks to humans.



Figure 3https://commons.wikimedia.org/wiki/File:Red_lionfish_near_Gilli_Banta_Island.JPG


The lionfish natural habitat is a wide range through the South Pacific and Indian Oceans. Their beautiful coloring and fins make them a joy to watch. But you may find close proximity during a dive to be an uncomfortable encounter. The lionfish has a venomous sting capable of delivering extreme pain lasting for days (and even paralysis). By day they may hide in rock or coral crevices, although lionfish in the Atlantic appear more active during the day, whether solo or in a group.


Sea Anemone

Figure 4https://commons.wikimedia.org/wiki/File:Actinodendron_arboreum2.jpg


Sea anemones are actually related to corals and jellyfish. Some species of anemones live in soft sediment on the ocean floor, while others float near the surface. Their tentacles have stinging cells with various venom toxins, including neurotoxins. Anemones use their stinging tentacles to paralyze prey for feeding. A majority of anemones are harmless to humans. However, there are a few very toxic species able to cause serious injury to unwary individuals. Actinodendron arboretum is one (also known as hell’s fire anemone).


Sea Urchin

Figure 5https://en.wikipedia.org/wiki/File:Riccio_Melone_a_Capo_Caccia_adventurediving.it.jpg


These spiky critters are fascinating and beautiful. They live in the world’s oceans in warm and cold waters. You’ll find them more often in shallows around rock pools and coral reefs. Be cautious to avoid stepping on them or handling them, not only for conservancy, but also to spare yourself pain. A sea urchin sting can puncture the skin, causing an open wound. The sting is painful. The open wound is also an infection risk. A bigger concern are multiple punctures, which can lead to weakness, muscle pain, shock, or even paralysis. Respiratory failure is possible and potentially fatal.


Fire Coral

Figure 6https://commons.wikimedia.org/wiki/File:Millepora_fire_coral.JPG


Once again a species on this list is not what it seems! Fire coral is not actually a coral. They are hydrocorals and closely related to hydra (small fresh-water organisms). You’ll find fire coral in tropical and subtropical waters on rocks and coral. The fire coral is not named for its coloring, which is bright yellow-green and brown and often mistaken for seaweed. Instead, the name is for its sting, which is delivered through tiny tentacles from surface pores. Touching the surface of fire coral will cause intense pain lasting two days or even up to two weeks.



Figure 7https://commons.wikimedia.org/wiki/File:Stone_Fish_at_AQWA_SMC2006.jpg


We saved the most dangerous for last. The stonefish is known as the world’s most venomous fish. Their sting can result in death if not treated. Stonefish venom actually lowers white blood cell count and can contribute to infection after initial treatment is performed. You’ll find them in Australia, where stonefish antivenom is the second highest antivenom administered. Their coloring blends in with rocks and natural surroundings and contributes to potential stings. That is true for water or land, given their ability to survive up to twenty-four hours out of water.


So how can you protect yourself from these spines and stingers? There are a few steps you can take:


  • Dive, scuba, or snorkel with a partner when possible
  • Be aware of potentially dangerous species in the geographic area of your activity
  • Educate yourself on steps to take when stung by various species (before it happens)
  • Protect your skin with wetsuits and divesuits like SlipIns DiveSkins
  • Refrain from touching coral, anemones, and urchins


We’d love to read your story! Share your encounters with ocean spines and stingers in the comments section below.



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