Venomous fish generate a potent toxin detrimental to people which they transfer by prick, sting or stab. Venomous fish are found in almost all aquatic ecosystems, but usually in tropical waters around the world. The most important venomous animals in the Black Sea coasts are greater weever (Trachinus draco), scorpion fish (Scorpaena porcus), common stingray (Dasyatis pastinaca) and stargazer (Uranoscopus scaber) (Fig 1).
Fig. 1. Venomous fishes from the Black Sea coasts (red line: venomous rays, blue line: venomous spines)
- More dangerous member of Scorpaenidae family occurring in Black Sea is weever Trachinus draco. It is a fish with elongated body and angular head. Like many other benthic predator fishes weever have big protruding eyes in the upper part of head, and a very big mouth. This fish (anglers sometimes call it snake) prefer soft bottom habitats – sand or silt. It digs into the bottom leaving only its eyes on the surface, and watches the prey – smaller fishes. When disturbed, weever spreads noticeable black dorsal fin, all five rays of which are venomous spikes. Like scorpion-fish it possess directed backward venomous spike on each of the gill flaps as well. There were cases of accidental stomping on weever’s rays on sandy shallows in Mediterranean Sea; so far, no such cases are known at Black Sea coasts. The consequences of the weever pricks are much heavier (lethal outcome possible) than in the case of scorpaena. Injured person must be taken to hospital in any case.
Weever Trachinus draco, Black Sea
- Black Sea scorpion-fishScorpaena porcus. It is a monster: a big head covered with skin flaps, protruding red eyes, huge mouth with thick lips. Dorsal fin’s rays of scorpaena became poisoned spikes – venom glands locate at the base of each ray. Another couple of hard poisoned prickles grow from gill flaps. These thorns are scorpaena’s defense weapon, whereas its weapon of attack is a great many sharp crooked teeth. Scorpion-fish is a predator hiding between rocks and algae, indistinguishable from them due to the camouflage of color spots and skin shreds. Scorpaena waits until smaller fish approach within attacking distance – a violent rush follows and the prey being swallowed within a split second.
Everything in scorpaena’s ugly appearance tells about the menace; at the same time – it’s nice. There are grey, charcoal-black, pink, brown, purple-yellow scorpaenas – depending on the dominant habitat colors. It dwells mostly among underwater rocks, but also can occur on the sandy bottom; it is a usual, abundant fish reaching 50cm length. Scorpion-fish represent threat mostly for fishers – when they handle the catch. No cases of accidental pricks by scorpaena are known; just do not touch it.
- The common stingray(Dasyatis pastinaca) is a species of stingrayin the family Dasyatidae, found in the northeastern Atlantic Ocean and the Mediterranean and Black Sea. It typically inhabits sandy or muddy habitats in coastal waters shallower than 60 m (200 ft), often burying itself in sediment. Usually measuring 45 cm (18 in) across, the common stingray has a diamond-shaped pectoral fin disc slightly wider than long, and a whip-like tail with upper and lower fin folds. It can be identified by its plain coloration and mostly smooth skin, except for a row of tubercles along the midline of the back in the largest individuals.
Like in all sharks, their skeleton is composed of cartilage. However, stingray has one long – up to 20cm – bone: tale prickle. It is a saw-edged, very sharp, pointed blade. Being disturbed, stingray uses its tale as a weep against invader, sticking out the prickle at the same time. Resulting wound may be deep and severe one. Fortunately, these rays are very scary, and rush away from swimmers and divers.
- The stargazer (Uranoscopus scaber) is a marine, subtropical fish of family Uranoscopidae. Its body is suited for living on the sea floor, and is one of few fish capable of bioelectrogenesis, or the ability to generate an electric charge. It is widespread along the Atlantic coast of Europe and Africa, is very common in the Mediterranean and Black Sea, and somewhat rare in the Bay of Biscay.It is a demersal fish, which lives in sandy or muddy sand sediments along the upper slope of the continental shelf, between depths of 14–400 meters. It is not an economically important fish, primarily caught as by-catch, but is ecologically important. Typical of stargazers, its body is somewhat dorso-ventrally flattened, lacks a swimbladder, and has been found as large as 35.0 centimeters in length, but is usually between 20 and 30 cm. Its head and jaws are rotated upward, and has very large eyes and mouth. Its body is brown in color and can have numerous small light spots, with a lighter belly. It lives to about 5 or 6 years, and females are larger in size than males.
Stargazer Uranoscopus scaber,from Black Sea
Black Sea spiny shark, piked dogfish Squalus acanthias, Russian name katran, like all fish species listed above may represent threat only to fishermen when they handle the catch: two venomous spikes in front of dorsal fins being raised as a response to disturbance. Dogfish prefer colder water, and during the warm period of year, it stays beneath summer thermocline – deeper than 20m.
Black Sea fish species lists accounting for all species ever reported in the Sea include small-spotted catshark Scyliorhinus canicula, and even hammerhead shark Sphyrna zygaena; these list entries correspond to a few occasional intrusions in past hundred years. These sharks are unable to settle in Black Sea because of its low salinity and low water temperature in winter.
Bibliography
http://blacksea-education.ru/e3.shtml
https://dergipark.org.tr/en/download/article-file/1303800
https://en.wikipedia.org/wiki/Thornback_ray
https://en.wikipedia.org/wiki/Common_stingray
Author: Giuglea Raul – President of ECOM
