Are there stone fish in the Caribbean

Poison fish: the scorpions of the seas

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Vienna - you look great. Their tentacle-like fin rays act like lion's manes, which is why the animals are often called "lionfish" in English. The pretty red and white coloring, however, should be understood as a warning signal. Lionfish from the genus Pterois are not to be trifled with! Most of their fins are equipped with spines, on the flanks of which there are special grooves. These in turn serve as channels for a nasty mixture of toxins, which is produced by double glands at the base of the fins. With such an armament, the lionfish need fear few other sea creatures. So it's no wonder that they can be easily observed. But don't touch it!

There are more than a dozen different species of lionfish around the world, but the most common is the Pacific species Pterois volitans. It lives in the tropical marine areas of Southeast Asia and Australia and prefers to hang around on reefs or in lagoons. The animals were introduced to the Caribbean and the Gulf of Mexico over 20 years ago, where they are now a real nuisance - not just for tourists. The lionfish decimate the native fauna. Ecologists would like to get rid of the swimming invaders.

The poison in the spines

Pterois belongs to the family of Scorpaenidae, German scorpion fish, there are also poisoners. The red scorpionfish (Scorpaena scrofa), for example, is found in the Mediterranean. As a popular food fish, it comes in the "bouillabaisse". Before gutting, however, the poison spines must be cut off, preferably with kitchen scissors. The dragon's head does not pose a threat to bathers because it is practically only found in water depths of 20 meters or more.

The stonefish of the genus Synanceia, on the other hand, behave quite differently, as they like to seek out shallow water. Their name could hardly be more appropriate: With their wrinkled skin and markings, they can hardly be distinguished from stones overgrown with seaweed. Until you step on it. In terms of defense, stonefish are the most poisonous fish species ever, explains James Diaz of Louisiana State University in New Orleans. The doctor has treated patients with stab wounds caused by Synanceia and Pterois several times. Fortunately, deaths are very rare, only two have been scientifically documented. Nevertheless, the injected toxins cause extreme pain and often severe swelling.

The toxins themselves are complex proteins with different effects. One of them, stonus toxin, destroys cell membranes and can also cause severe cardiac arrhythmias. As protein constructs, however, the molecules are sensitive to heat. The most important emergency treatment, therefore, is to soak the affected part of the body in hot water and hold it in for 30 to 90 minutes, Diaz said. The temperature should be 45 ° Celsius if possible. Although this is also uncomfortable, it slows down the symptoms caused by the poison.

Wound rot as a worst-case scenario

There is an effective antidote to the toxins of stone fish. It is only needed in severe cases, as James Diaz explains. Under no circumstances should the limb hit by the sting be tied off. The poison must drain through veins and lymph vessels so that the body can neutralize it as quickly as possible. Furthermore, Diaz recommends a tetanus vaccination if not available.

The triggers of tetanus, bacteria of the species Clostridium tetani, not only live in the ground, "they also thrive on beaches because a lot of organic material rots there," says the expert. The fish spines can therefore be contaminated with the germs. Clostridium tetani is not the only marine pathogen. Other microbial species such as Vibrio vulnificus are specially adapted to life in salt water. They need iron, explains, Diaz, and they like to get that from blood.

"Healthy people can rely on their immune systems to keep Vibrio in check." In the case of immunocompromised people or people with liver disease with a high blood iron level, however, the tiny creatures sometimes cause nasty ulcers - up to wound rot. Then only a surgical intervention will help. Just like pterois, stonefish are a tropical species that live on the beaches of Thailand and the Great Barrier Reef in Australia, among other places. If you want to avoid unpleasant encounters, wear sandals with thick (!) Soles and do not attack anything suspicious in tide pools. Hobby cooks should also beware of scorpaenids at fish markets. The toxins are effective for more than 48 hours after the animals have died. You don't want to end up in hospital because of a bouillabaisse. (Kurt deSwaaf, July 8th, 2017)