Venomous Reef Marine Life

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Forget being eaten by sharks. The reef is home to an amazing array of fish, and well over 200 species of them are known or thought to be venomous. With names such as Stingrays, Scorpionfish, Lionfish, Stonefish and Surgeonfish you can’t say you weren’t warned!

Let’s take a closer look at the notorious Scorpaenidae family, a.k.a. the ‘Reef Mobsters’. This gang will not hit you with M-16 machine guns or hand held rocket launchers but instead will sneak up with different sorts of specialized venomous spines. The good news is that these fish only use their venom for defense. Most accidents come from handling them in aquariums and stepping on one as they inject the toxin through their spines directly into the predator (including you, when you accidentally disturb them).

There are over 300 members of the Scorpionfish family, Scorpaenidae of which 57 are listed as venomous. They can be divided into 3 distinct groups based on their toxicity and venom organ structure (refer diagram 1):

  • Pterois – Long slender spines with small venom glands and a less potent sting (eg, lionfish, zebrafish, butterfly cod)
  • Scorpaena – Shorter and thicker spines with larger venom glands and a more potent sting (eg, scorpionfish, bullrout, sculpin)
  • Synanceia – Stout powerful spines with highly developed venom glands and a potentially fatal sting (eg, stonefish)

By the way, although Scorpionfish are capable of producing and discharging toxins, they are edible, and tasty as well, if you can get past their ugly appearance!

Lionfish (Scorpaenidae)

The majestic Lionfish is really the rose among the thorns in the Scorpaenidae family. This family contains several genera of Lionfish (also known as turkeyfish, featherfins, scorpioncods or zebrafish.) The two types of lionfish are easily separated into the genera Pterois and the Dwarf Lionfish belonging to the genera Dendrochirus. Despite their beautiful appearance, they can deliver a nasty sting and watch out for the Pterois genus which is highly venomous. The elongated spines on their fins are covered with thin lacy tissue, giving them a fragile appearance as they sway in the current.

Unlike their more sedentary relatives, Scorpionfish and Stonefish, Lionfish are active hunters. At night, they emerge from the caves and holes that they hide in during the day and slowly cruise their neighborhood, using their fins to herd and trap the unlucky prey into a dead end. They then open their huge mouths to vacuum in the prey. Some members are quite happy to cruise the reefs in daylight as well.

Scorpionfish (Scorpaena)

The scorpions of the sea, the Scorpionfish, are often found on sandy or rocky bottoms in shallow waters. Their skin is often mottled with patches of red or brown which resemble rocks, sponges and seaweed, making them difficult to see against the reef. They are not aggressive, but if threatened will erect their dorsal spine. In the face of danger, they usually flee only a short distance, and then freeze, merging into the background. Their spines are covered by tissue (as in the Lionfish) but the main difference is that the tissue is much thicker. In general, Scorpionfish stings are not as painful as Lionfish, although there are a few species whose venom can induce almost the same degree of suffering. Scorpionfish produce a floating, gelatinous mass in which the eggs are embedded, in the same way as the Lionfish.

Stonefish (Synanceiidae)

The Stonefish is the most venomous of all fishes, and can even penetrate the soles of tennis shoes, if stepped on. The wounds are small, sometimes only 3/4 of an inch deep, but the venom is extremely potent. Each venom sac contains 10 milligrams of venom (by comparison, a postage stamp weighs 65 milligrams). The Australian Aborigines are known to perform an ancient dance ritual portraying the dangers of the Stonefish. In the dance, a young man steps on a Stonefish in a shallow rock pool as he looks for food. It causes a painful death, bearing a message today that is as important as it was in ancient times, and so educating their children on the dangers of the Stonefish.

The Stonefish wins every ugly-contest outright, with its warty and bumpy complexion. Its pelvic fins are fleshy appendages that look almost nothing like fins, and with its scarcely visible eyes and mouth, the fish looks like a rock lying on the seabed. It’s been suggested that Stonefish exude a white, milky substance over their bodies, which encourages plant growth (i.e. algae and other organisms such as sponges.) This adds further to the camouflage. Their habit of lying motionless causes them to be overlooked and so used as a pathway by mollusks, shrimps and other benthonic marine animals. Stonefish lie in wait for unsuspecting smaller fish to wander into range before they are sucked into the stonefish’s capacious mouth.

Fi日st Aid

The sting from these fish is quite painful, and most people have a different reaction to it. In the case of Scorpionfish and Lionfish, a person punctured by one of the sharp spines is immediately in pain. Swelling of the wound and nearby areas occurs. Often the victim is unable to move his or her arms or legs due to the swelling. Other symptoms include nausea, breathing problems, paralysis, delirium and convulsion. Despite this only the stonefish is deadly.

In all cases remove the spine(s) from the wound. Do not stop the bleeding as this encourages the removal of some of the venom. As most marine toxins are broken down by heat, the wound should then be submerged in hot water at as high a temperature as you can stand, for 30-90 min. A quick start with the hot water treatment is vitally important. The addition of sodium chloride or magnesium sulfate to the hot water is optional. Get medical help immediately. On boats, a source of hot water is the outboard engines. These engines use water as a coolant, and this becomes quite hot in the process. It’s possible to get some of this and use it for first aid. A Stonefish anti-venom is available (it’s produced in Australia) but should only be used under professional medical supervision.

Even though these Mobsters are painful, sometimes even deadly, you can easily avoid them by good buoyancy control and staying above the reef. In this way the reef won’t hurt you and you won’t damage the reef.

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