Dolphins Tenerife

It is well known that the extinction of the dinosaurs, probably caused by the collision of a meteor with the earth, promoted mammals’ development and their domain over the ecosystems dinosaurs used to occupy. Twenty million years later, in the shores of the Tethys Sea was occurring something interesting. Some land animals began to feed on sea food and slowly, after thousands of years, they lost their back limbs changing them into fish tails that allowed them to move better in the water, and stay more and more time in the water. Those animals were whales, porpoises and dolphins ancestors, or in other words cetaceans’ ancestors.

The Tethys Sea was located 45 millions of years ago in the region where is now located the Mediterranean Sea. The southern coast of the sea in Africa was far away from the coast of Europe. What is nowadays called the Strait of Gibraltar was much wider. The southern coast of the Tethys Sea was located 250kilometres to the south of Cairo in the area of the Uadi Rayan valley, in the province of Al Fayum. It was there, near the coasts of the antique sea, where the events that developed in the origin of the cetaceans took place. There is only other place in the world where archeologists can find such detailed story about the primitive cetaceans; this region is Pakistan, which millions of years ago were located at the shores of the Tethys Sea too. In that area, scientists have also found predecessors of the present whales and dolphins.

Primitive cetaceans had a particular type of hoofs that belong to the Artiodactyla family, which includes all the animals with a pair number of toes. In this family are included camels, giraffes, caws, antelopes, llamas, pigs and hippopotamus. Probably, cetaceans are descendants of these last ones.

The Pakicetus specimen found in Pakistan looked like a dog with a wide tail and hoofs. This animal lived on earth 53 million of years ago. Its name finishing in “cetus” indicates that it is a predecessor of the present dolphins and whales. The evolution process that started with the Pakicetus and ended with the present cetaceans was not easy and there were many animal species in the middle. Two of those intermediate species in the cetaceans’ evolution were the Basilosaurus and the Dorudon. These are the most common fossilized species found in the “Valley of the Whales” in Wadi Al-Hitan, Egypt. The Dorudon had about 5 metres long and the Basilosurus had almost 18 metres long. Both species had the predominant characteristics of the cetaceans.

Those prehistoric animals used to live in the coastline of the Tethys Sea and they were carnivores that used to feed on fish and mollusks. The carcasses of the ones that dyed deposited in the bottom of that sea for generations becoming fossils after million of years. Today, we can find in the Valley of the Whales the cemetery of cetaceans that used to live in the Tethys Sea. Fifteen different kinds of whales where found there, in the marvelous outdoor natural life museum that is the Valley of the Whales. Scientists have found complete skeletons of primitive cetaceans including their ribs, spine, skull and teeth. Apart form primitive whales, the valley also has fossils of turtles, dugongs and manatees (both Sireniaes), fish, sharks and invertebrates.

Nowadays there are two types of whales. On one hand there are teethed whales called Odontocetus, and on the other hand there are baleens or whalebones whales called Mysticetus. In the history of cetaceans’ evolution Mysticetus came later because in the Valley of the Whales only Odontocetus were found. These last, are the predecessors of the present killer whales and dolphins. One missing piece in the Odontocetus specimens is the “melon” organ that dolphins and killer whales use to emit ultra-sounds, which functions like a sonar transmitter to locate their preys. For that reason, it is believed that dolphins and killer whales came later in the evolution process.

Dolphins are sea bats

Twenty million years later, after the time when the Odontocetus used to live and die in the Wadi Al-Hitan valley, the Tethys Sea had narrowed because Africa was approaching to Europe and the Arabic Peninsula had collided with Asia, closing the flow of water in that region. Those events made the sea currents change dramatically, forcing marine life to evolve to readapt to the new environmental conditions. In that period dolphins developed the “melon” organ and their sonar system because the waters turned cloudy and they couldn’t see their preys.

A living example is the Ganges River Dolphin, which is almost blind because the waters of the river are too muddy to see anything with their eyes. The ultra-sound system of dolphins is similar to the one bats have. Humans can hear sounds up to 20,000 cycles per second, while dolphins can hear sounds up to 100,000 cycles per second. We call ultra-sounds any sound above 20,000 cycles per second. That is why dolphins use ultra-sounds to “see” in dark or cloudy waters their preys.

The ultra-sound system of dolphins functions like a sonar transmitter and it allows them calculate the distance and direction of their prey, their size, speed and course. This way, they use ultra-sound as we use our eyes.
Dolphins use an organ located in their forehead called “melon organ”, which using compressed air emit ultra-sounds. The echoes of those sounds are received and interpreted in an area located around their head and in their lower jaw. This area makes a detailed analysis of the sound received. The ultra-sound system some animals have is called animal echolocation, and one of its characteristics is an asymmetric skull shape. To study fossil skulls’ symmetry is a good way to know if an animal used ultra-sound for hunting. An ancestor of the modern dolphin is the Kentriodon, which already presented an asymmetric skull, and although scientists think it didn’t function as good as the one modern dolphin have, it is a sign and a point of departure for the evolution of the echolocation in this kind of cetaceans.

The Whale and Dolphin Conservation Society (WDCS) reported the killing of 600 dolphins in the coasts of the Feroe Islands between June and July 2010.

The environmentalist society reported that the dolphins hunt is common in these islands, which are located in the North Atlantic Ocean between Scotland and Iceland. The cetaceans hunt that Denmark carries out in this area “haven’t been prohibited or regulated by the international community, in spite the high levels of toxins found in the meat and fat of these marine mammals”.

The environmental society reported four coastal communities to be responsible for killing cetaceans. In Sandageroi 108 dolphin specimens were killed, in Klaksvik they killed 250 dolphins, in Húsavik 193 and in Vestmanna 50.

The cetaceans hunting activities increased after two years of low numbers. In 2008, there wasn’t any hunting after the doctors of the Feroe Islands said that the meat of the dolphins wasn’t suitable for human consumption due to the high levels of toxins founded in their tissues, organs and fat. One year after, however, dolphins hunt increased to 500 specimens.

The pilot whales hunting, as well as other smaller cetaceans’ species hunting is a common practice in the Ferole Islands where their meat is used for human consumption. Although pilot whales are an endangered species, countries such as Japan or the Feroe Islands continue their hunting activities without any international censure or control, because the International Whaling Commission, which is the international entity in charge of conservation and protection of cetaceans, focuses only in the protection of larger whale species such as the sperm whale or the killer whale, while the pilot whale is considered part of the dolphins family. However, many members of the IWC consider that the commission has authority in the protection of smaller cetacean species such as the pilot whale.

Next year from 21st to 23rd of March, the city of Cádiz, in Andalucia, and the Strait of Gibraltar will be the venue for the 25th edition of the European Cetacean Society conference (ECS), organized by the European association CIRCE (Conservation, Information & Research on Cetaceans), which will gather an large number of the most important European scientists and researches. This is the first time this Spanish city is to host such an important event.

A Spanish city is selected again to be the venue of this conference due to the hard work Spanish researchers have been carrying out for the last twenty years in the field of cetology, making Cádiz the fifth Spanish city selected to be the venue of this conference. The first ECS conference in Spain was in 1990 in Palma de Mallorca, the second in Valencia in 1999, the third in Las Palmas in 2003 and the last in San Sebastián in 2007. The researches of the Strait of Gibraltar are represented by the CIRCE association as well as local entities dedicated to the study of cetaceans.

The event will take place at the “Palacio de Congresos de Cádiz” in March 2011, receiving about five hundred participants form forty different countries. During the conference that will last three days, the last results of the researches about marine mammals will be presented, through lectures and written works.

This event is also focused in promoting volunteering among young people, and for that reason, young people form any European country and Spanish community will have the chance to help the organizers during the conference, having the opportunity to meet many renowned international scientists.

Before this conference, a series of workshops about cetaceans’ study and conservation will take place, which will be conducted by specialists in each field. These activities will turn Cádiz and the Strait of Gibraltar in the point of reference for the marine mammals’ research in Europe.
Tourist promotion

After the congress, the participants will have the chance to make whale watching trips in the Gulf of Cádiz and the Strait of Gibraltar as well as tours to the “Parque Natural del Estrecho” (Strait’s Natural Park), the “Parque Natural de los Alcornocales” (Cork Oaks Natural Park) and the Baelo Claudia archeological complex in Tarifa.

The congress is not only intended to researchers and students but to public in general who will be able for two consecutive nights to attend to talks about cetaceans and watch a video about marine mammals with the purpose to promote conservational awareness about these animals.

The celebration of this congress is not only relevant for the scientists and researchers community but also for the promotion of whale watching ecotourism in the area of the Strait of Gibraltar. This way, the organizers are trying to make known one of the most important locations for whale watching in Europe, because in these waters can be found seven species of cetaceans, from fin back whales to dolphins, although the most popular species among tourists are the killer whales that can be seen in spring near the coastline of Cádiz and also in summer during the tuna fishing season.

This congress is a good opportunity for the Campo de Gibraltar community and for Cádiz to get known at an international level for its natural resources and for the marine life research that is carried out in different levels.

The program that this Spanish national park is developing focuses in the study and protection of the cetaceans that live near the coast of Galicia in the north of Spain. The “Illas Atlánticas” National Park has got this project under way in collaboration with the “Coordinadora para el Estudio de Mamíferos Marinos – CEMMA (Coordinating Committee for Marine Mammals Research). To achieve the project’s goals, a network of hydrophones will be installed in the waters of the Cíes Islands, and underwater cameras will record the movement of the main cetacean species that live in the waters near the “rías” (long, narrow, tidal inlets).

Hydrophones have been used by CEMMA since 2005 for the study of the movement and behavior of the marine mammals through the listening of the sounds they emit. The park heard about this technology and for the last five months has been looking for the perfect locations to install these hydrophones in the waters surrounding the islands to cover the biggest possible area (each hydrophone covers an area of 500 meters) and to have an easy access to them.

These devices have a battery that lasts three months, but due to weather and temperature conditions, the battery will be replaced each month when data is collected. Currently, the hydrophones are been installed in the buoys located in Cíes, Ons and Sálvora and also in Cortegada where they will be operating for at least 12 months.

Each cetacean species (whales, dolphins) emit different sounds and these sounds vary according to the message these marine mammals want to transmit. The study of these sounds will allow knowing the exact number of family groups in these waters, their distribution, movements and migratory routes.

Apart from that, the sounds’ recording will allow the research of their behavior patterns through the study of their language as was explained by Luz Santos, coordinator of CEMMA. “To unveil the mystery of the language of one of the most intelligent animals in the world is the goal of any marine biologist”, she said.

Different dolphin species can be found in the “Riás Baixas” region, but the bottle