Hazardous marine animals
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  Hazardous marine animals in the Black Sea  


The Black Sea is a friendly sea, for there are very few hazardous marine animals- even for children. A few species that can be annoying are listed below.


Rhizostome jellyfish Rhizostoma pulmo can sting your skin with its thread-cells located on the lacy peristomal tentacles. It is better to avoid it when swimming; Though nettle stings stronger than this jellyfish.



Moon jellyfish Aurelia aurita is another Scyphozoan medusa common in the Black Sea. Its thread-cells located on the canopy fringe tentacles are less potent weapon than those of Rhizostoma; they cannot penetrate even children's skin. Contact of this jellyfish with eyes  still should be avoided.

Jellyfish immobilize or even kill their prey (small planktonic animals mostly) with the use of thread-cells containing venom capsule with a sharp, saw-edged coiled harpoon attached to it.


The spring uncoils and hit the prey when it touches sensitive hair on the thread-cell surface. Spike of the hollow dart breaks inside the victim body, and paralyzing venom pours out. Thread-cell is a disposable weapon.



Coelenterate thread cell action


Interesting is that newly hatched silvery horse-mackerels often crowd between Rhizostoma tentacles, and travel with jellyfish. Thread-cells do not harm these tiny fishes - just like tentacles of tropical actiniae don't act on clown-fish living between them.

Black Sea scorpion-fish Scorpaena 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.


Black Sea scorpionfish Scorpaena porcus


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.



Noticeable scorpion-fish Scorpaena notata


Another local species of scorpion-fish is noticeable scorpionfish Scorpaena notata, it does not exceed 15cm, and has smaller supraorbital skin flaps than those of Scorpaena porcus. Wounds inflicted by Scorpaena's venomous spikes severely hurt and swell, then general allergic reaction follows: weakness, raised body temperature, headache. No lethal cases after Scorpaena wounds were registered. Helpful is antihistamine medication under doctor's supervision.


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


Skates are flat benthic sharks; they have no sides - only back and belly - dorsal and ventral surfaces. They swim waving with their "wings" - flattened body sides, whereas their tailfin is reduced to tail-stem. They live on the sandy or silt bottom, and find their food on the bottom: shellfish and small fish. Two species of skates live in the Black Sea: larger (its length up to 1.5m, with tail) thornback skate Raja clavata, and smaller (< 0.7m) common stingray Dasyatis pastinaca.


Common stingray Dasyatis pastinaca, Black Sea

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.


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.


No more dangerous marine creatures in the Black Sea. Kids often ask: Do crabs bite? They don't bite - they pinch - and only when we grab them!







The following pages of this web-site are available only in Russian:


Black Sea Marine Life - sandy bottom - fishes, crabs, mollusks...

Black Sea Marine Life - sandy bottom - let's think about it
Black Sea Marine Life - submarine rocks - near the surfline

Black Sea Marine Life - submarine rocks - deeper

Black Sea Marine Life - submarine rocks - even deeper

Oil pollution, coastal deforestation, etc.

Aegean Sea - compare to Black Sea

Русская версия