Whales and dolphins in the Mediterranean
The secrets of the Sea: In the Mediterranean there are sperm whales, pilot whales, finback whales and a great variety of dolphins. In fact, there are a total of 21 species of marine mammals, almost a quarter of the 86 species existing in the world.
Although these sea creatures principally live in the area of the Straits of Gibraltar and in Italian waters, whales and dolphins are to be found in the waters around Mallorca too. "Apart from the species mentioned above, it is also possible to see Cuvier’s beaked whale, the common dolphin, the white-sided dolphin, Risso’s dolphin and the mular or bottlenose dolphin", so we are told by someone who should know, namely, the marine biologist Beatriz Morales, of the Mediterranean Institute of Advanced Studies (IMEDEA) at Esporles on Mallorca. Frequently, the dolphins accompany the boats in the waters around the Balearic Islands and they are even to be glimpsed in the coves around the coast such as at Cala Llamp.
There is still no data relating to the population of aquatic mammals (cetaceans) in the Mediterranean and only estimates are available. This is due to various reasons. These counts – ‘surveys’ as the experts call them - are very expensive and many experts even consider them unnecessary, to the extent that neither the whales nor the Mediterranean dolphins belong to those species in danger of extinction. The sole exception is constituted by the finback whale that may attain up to 70 tonnes in weight. It is the second largest species of whales after the blue whale, the largest whale that exists on our planet.
Despite there being no exact figures, there do exist a series of research studies into their ways of life, e.g. of the finback whale and the sperm whale. These appear to be very tranquil creatures. Unlike many of their kind that undertake long journeys, for example from the polar regions to regions close to the equator, these two Mediterranean species are rather sedentary. They are defined as ‘residents’; in the opinion of the scientists these creatures have no interest in crossing the oceans, from one end of the earth to the other.
So what lies behind this behaviour pattern? In order to find a partner and give birth to their young they need warm waters; given that in the Mediterranean the water temperature – in comparison with certain other oceans – is kept relatively warm, they are not obliged, so the experts believe, to go in search of warmer waters and thus simply "remain at home".
How have they arrived at this conclusion? By analysis of the genetic make-up of the whales they have discovered, for example, that the DNA of the finback whales, native to the Ligurian Sea, is different from that of finback whales found in the North Atlantic. From this they have deducted that the Mediterranean whales never leave the confines of "Mare Nostrum".
English and Latin names:
Cuvier’s beaked whale (Ziphius cavirostris)
Risso’s dolphin (Grampus griseus)
Mular or bottlenosed dolphin (Tursiops truncatus)
White-sided dolphin (Lagenorhynchus obliquidens)
Common dolphin (Delphinus delphis)