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Rambler's Top100

 
 
 
 
 
Русская версия
  Black Sea dolphins  
 

 

 

Dolphins are the only whales occuring in the Black Sea: they are smal-sized toothed whales (as compared to their relatives such as sperm-whale or orca). At the same time, they are the largest marine animals in the Black Sea; it may be worth reminding, that dolphins are not fish, they are mammals - which means that they they are viviparous, and feed their calves with milk, and they use lungs to breath air. To breath they have to coming up to the surface; at those moments we see their backs emerging among waves, and often can hear sounds they produce exhaling the used air. Dolphin's "nose" - blow hole - is situated on the back of animal's head. Usually, dolphins dive for only one to three minutes, but they are capable of staying underwater for ten minutes, going down for dozens meters.

 

Sometimes going shipboard we can see dolphins get a place in the bow wave and travel with it, jumping and playng in the streaming surf. Dolphins love playing indeed, and that is a character marking them as animals with complex behavior and advanced brain: by means of games dolphin calves learn signals, rules of communication and interaction within the family school, hunting techniques, and many other tricks. Apart from the useful training games of dolphins' kids, sometimes it seems that dolphins just enjoy playing - for example we've seen them playing "volleyball" with a big Rhizostoma jellifish - punching it out of water with their muzzles.

 

Sounds produced by dolphins - sounds like whistles, snapping, trilling - over ten different signals, resound far in sea: water is much better transmitter of sounds than air. Some of dolphins's sounds are ultrasonic ones - we can't hear them. These very high frequency sounds are used for echolocation - reflection of ultrasonic waves from underwater objects returns to dolphin, telling animal of the distanca, size, form, direction of movement and speed of the object. Thus they know of the proximity of the bottom, learn about other members of their family location, find out about fish schools that are still out of visibility (which is particularly important in the quite turbid Black Sea, especially in its nearshore waters). Trainers at dolphin shows use ultrasonic whistles to give a command to dolphins to perform a trick. Still communication signals used by dolphins - sounds and movements - do not make up for a real language: only words, no phrases.

 

Dolphins live in family packs - all members of the school are relatives, this is thoght to be the reason for their mutual assistance and developed co-operation. They always help their wounded or just weakened kin to keep on the surface, don't let it drown supporting its body from beneath, pushing it upwards. There tales about similar cases of dolphins' help to drowning people; it's being suggested that dolphins can treat human as their kin. Legends of dolphins helping people are abundant, some of them date back to ancient times; many of them sound more like fairy tales; still there no proven case of dolphin's hostility to man.

Bottlenose dolphin (Tursiops truncatus) is the most common species of dolphin in the Black Sea nearshore waters; this dolphin is common at the coasts of all continents, in all oceans, except polar regions. Bottlenoses are also most popular actors in dolphin shows, they endure captivity easier than other dolphin species. They learn show tricks very fast: dolphin trainers tell that it's usually enough just single correct performance awarded by a fish, for the signal-trick-award procedure became a habit. On the other hand, dolphins may as easily forget the learned trick - if not awarded, even once.


 

Big dolphin's heads contains big brain indeed, but it's not for lot of thinking: it's just that big body requires many neurons to govern it (blue whales or elephants have even bigger brain). Still dolphin's brain have one very unique feature: it never sleeps. Left and right hemispheres of dolphin's brain sleep in turns, one after another, because dolphin need to emerge on surface for breathing. At night this diving-surfacing behavior is controlled by the two brain hemispheres working in shifts.

 

People started to study and train dolphins in the middle of twentieth century, for dolphins' shows and for military purposes. The results of that work were so successful and so widely advertised, that soon a legend of unusually high dolphins' intellectual level formed. Sometimes one might hear (mostly from movies) that dolphins are almost as clever as human, only they have "another kind of mind". Modern scientific knowledge of dolphins' brain and behaviour puts these marine mammals' learning ability on the level of a dog; a long way to anthropoid apes.

 

Still something makes us treat dolphins in somewhat different way than other human-friendly animals. Joyful, cute, nice, friendly - all true about dolphins. And, yes - they sometimes helped people in the sea. Kids (and adult people too!) love playing with them in oceanariums, at dolphin shows: dolphins themselves come and play with people. Also, dolphins always smile! Of course, one might say that it's just structure of their sculls and facial muscles... Still - they smile, and their smile looks more genuine and sincere than smiles of many people; this big smile on a big face with big cheerful eyes - it makes everyone smile too. Usually, after swimming with dolphins, people keep on smiling (with no other special reason) half an hour - on the average. A course of dolphin therapy helped many kids suffering nervous disorders.

 

Skin of dolphins is a miraculous tissue, it's capable of extinguishing turbulent vortexes, that usually slow down any swimming body - this another secret of dolphins' very fast swimming; submarine designers took dolphin's skin as a model for building covers for their sisnister machines. The appearence of dolphin's skin is deceiving: it looks like hard shiny plastik, but when you stroke a dolphin passing by you, the feeling is like you touch a fine silk.

 

Dolphin's trainers and scientists can tell some very non-miraculous, even cruel stories of their favorite animals' life: of a severe rules of hierarchy in dolphins' family-pack, of hard and tough supression of a week individual; dolphins are animals. Still all trainers, knowing all that, love their trainees, we all love them; and after all attempts to explain what we love them for - smiles, beauty of slender streaming bodies, their games, playing with us, escorting our boats etc. - still something inexplicable remains - dolphins are the best in their very special way.

 

Occasionally we hear that dolphins (or whales) get washed ashore, sometimes they purposefully swim to the shore and waves throw them on the beach. This can happen when marine mammals get sick, e.g. injured, or poisoned (for example, after eating fish that have accumulated toxic planktonic algae during red tides). Scientists discovered another one mechanism of the dolphins' unusual urge to land. Sometimes , a combination of the shore curve, the type of bottom sediments, and wave power - all at one place - can generate a roar of the surf, that, among all cacophony of different sounds, contains a sound that is very similar to dolphin's (or whale's) signal meaning "help me!". Obeying to instinct dolphins rush to save their kin - and find themselves on the land. Dolphin that just was thrown on beach should not be immediately brought back into the sea: most probably the shocked animal soon be back out of the water; experts' advice is to keep landed dolphins in a pool filled with seawater (e.g. deep trench dug in beach sand), until the animal recover itself. Such cases with landed bottlenosed dolphins took place at our beach, and keeping dolphin in a pool for 1-2 days worked well.


 


Dolphins living in the Black Sea

 

Another cosmopolitan dolphin species, common dolphin Delphinus delphis can be rarely encountered at close proximity to the shores in Black Sea. This species, distinguished by whitish sides of the body, is more abundant off shore.

 

People living on Black Sea shores were always hunting dolphins: dolphin skin made a fabric for fishermen waterproof clothes, blubber being burned in lamps gave people light, and dolphin meat was just a kind of food. To the mid-twentieth century all species of dolphins in the Black Sea became endangered species. Most Black Sea countries banned hunting dolphins in 1960s, Turkey joined the ban in 1980s. Since then, populations of all three species of dolphins in the Вlack Sea are growing - very visibly. For example, porpoise - smallest and most suffered from hunting species of dolphins in the Black Sea (its blubber was rated most high) - was very rare at all coasts in 1990s; now porpoises can be seen at Caucasian coast, and in some areas near Crimean shore they became really common species of dolphin, sometimes outnumbering bottlenosed dolphins (e.g. entrance to Balaklava Bay). Still thousands of dolphins in the Black Sea continue dieing of unnatural causes each year; most usually they got entangled in fishermen nets, and suffocate not being able reaching seasurface. Some fishermen regard dolphins as competitors, and finding them still alive in their nets, finish them off. Nevertheless, growing numbers of dolphins showing us their wet black backs in the waves, is a very obvious, spectacular, and inspiring example of success in saving rare species of marine animals - a small piece of a whole marine life - by the desisive and concerted action of Black Sea people, nations, governments.

 

Common porpoise (Phocaena phocaena), or azovka, can be identified by a low, shortish dorsal fin, and short, fast breathing rolls over the sea surface - as compared to bottlenose and common dolphins

 

Bottlenosed dolphins (Tursiops truncatus)

 

Dolphins eat fish, a lot of it - each animal needs 10-30 kg fish a day. They are homoiothermal (warm-blooded) animals, and have to keep body temperature at over 30oC in sometimes very cold water (often around 0oC during Black Sea winters; average man survive several minutes at those condititions); also they swim fast all their life. Both maintainance of high body temperature in cold environment and swimming are extremely energy-consuming jobs. Subcutaneous blubber helps keeping dolphin warm serving both as a thermo-insulation, and as an intracellular stock of energy; adipose tissue is an active heater - burning fat is warming up dolphin's blood. Fuel stock needs to be replenished, and this why dolphins are always hunting, resting only during night sleep. They find fish scholls using ultrasonic echolocation and shortly overtake and surround them - there are no living creatures in the Black Sea swimming faster than dolphins. When the hunt takes place very close to shore, dolphins assume half-circle formation, and tightening the cordon push disconcerted fish flock almost to the beach, eating fish in surf waves. Sometimes it happens at depths less then one meter: dolphins' backs shine above water, their pectoral fins scraping the bottom.

 

 

 

Having overrun fish shoal in the sea, dolphins don't rush on the prey at random, each on its own; they encircle and concentrate fish (whistling, pounding of tailfins on waves, jumping out of water and bumping on seasurface help them doing it), and then feed - in order of pack hierarachy, one after another - starting from alpha male and his female. Having got food, a dolphin returns to its place in the cordon.

 

Dolphins always are where there are fish. For example, at Caucasian coast of Black Sea fish is most abundant in spring and autumn. In spring shoals of khamsi (Black Sea anchovy Engraulis encrasicholus ponticus) and mullet (Mugil cephalus and Lisa aurata) migrate along shore northward: from overwintering areas (deep places off Caucasian and Anatolian coasts) to the Sea of Azov, which is rich of their food (for khamsi it's plankton, for mullet - it's detritus). Huge schools of pilengas (large Far-Eastern species of mullet Mugil soiuy introduced into Black Sea) aligned in long trains move in opposite direction - from North to South along the shore; groups of bottlenosed dolphins, ranging from several to dozens of animals patrol near-shore waters intercepting migrating fish - sometimes making a spectacular show for those watching from the beach. In autumn fish schools travel back to overwintering areas, again - with dolphins chasing them. Hundreds of dolphins make a cordon in the gates of the Sea of Azov - Kerch Strait, meeting there all migrating fish.

 

In summer dolphins also are not rare near our shores, since mullets, horse mackerel, atherina are there. They can be met even near the most crowded beaches, but - mostly during the hours when there are less people there.

 

Learn about dolphins and whales, look for them - in the sea.

 

 

 

 

The following pages are available only in Russian:


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

Black Sea Marine Life - sandy bottom habitats - 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

 

This web-site is based on the fragments of the book Life of the Black Sea by Alexander Vershinin (2003, 2007), and the content of the Living Black Sea and Marine Life education programs in the Russian Federal Children Center Orlyonok. All content copyright, all rights reserved. . Text and photo images by Alexander Vershinin © 2001-2013