Cetaceans
When someone hears the word 'whale', one usually pictures a giant animal. However, the much smaller porpoises and dolphins also belong to the whale family. This can be further subdivided in baleen whales and toothed whales. The predecessors of the cetaceans lived on land. When they had to adapt to a rising sea leve during the Tertiary period (around 50 million years ago), they developed fins and a tail and became sea animals.
The largest baleen whales have no teeth. Instead they have baleen-bearing plates made from horn-like material, which hangs in rows in the palate of the upper jaw. The whales use these baleen plates to filter out their food. Most of these whales live off of krill: shrimp-like animals found in enormous amounts in the open sea. They will also consume small fish such as herring. Toothed whales are generally smaller than baleen whales. Only sperm whales are comparable in length with baleen whales. Dolphins and porpoises are also toothed whales.
Distribution
Porpoises, dolphins and larger whales are difficult to observe in the open sea due to their living style. Porpoises and bottlenose dolphins usually live close to the coast. Up till the 1960s, porpoises were common in the Wadden Sea and along the North Sea beaches. In 2005, marine mammals in the entire North Sea were counted from seven ships and three airplanes. The previous integral count dated back to 1994.
Large whales were rarely ever observed in the North Sea. Only the minke whale, the smallest baleen whale (8 meters) is regularly seen in the northern North Sea. If a sperm whale or any other large whale species ends up in the shallow southern North Sea, then it is usually a case of a lost or sick animal. Their chances of survival are small and they eventually wash ashore somewhere. Because the North Sea is warming up due to climate changes, an increasing number of whale species from warmer regions are being found in the North Sea, such as Risso's dophins, orcas and white-nosed dolphins.
Blubber boilers and premium hunters
All North Sea folk used to be involved for a shorter or longer period of time with the whale hunt. It concerned mostly obtaining the whale oil, which was boiled out of the fat layer and used for the production of lamp oil and soap, later on for margarine. Whales were also hunted for their baleen (for umbrellas and corsets) and for the amber - a raw material used in cosmetics. The meat from the whale was sometimes eaten. In order to catch the whales, the men went with ships to the northern Arctic Ocean or even further. In the 18th century, the hunt for slower whale species in the north was so intensive that they became very rare and it was no longer profitable to begin hunting whales. In the 20th century, the harpoon canon was discovered and the faster fin-fish could also be hunted. A new Dutch whaler, the William Barentsz, was launched in 1950. Sei whales in particular were caught with this ship in the southern polar region. However, after a few years, the catch was no longer profitable: the number of animals was also decreasing in the Antarctic seas.
The whale catch was controversial in the 1970s. In 1985, the International Whaling Commission ended the commercial whale hunting. The Netherlands was already an avid supporter. At the moment, the whale hunt has ended in most countries, yet even today countries such as Norway, Iceland and Japan are still trying to continue the whale hunt. The Norwegians also hunt minke whales on a small scale in the North Sea, under great protest from many. Due to the low price of whale meat on the Norwegian market, this hunting is not economically profitable. In Japan, whale meat is much more desired and therefore much more value. For these reasons, Norway and Japan are pleading for a revision in the trade restrictions for whale meat.
In 2000, Japan announced not only that they would hunt minke whales, but also Bryde's whales and sperm whales.
Whale hunting in the North Sea was never done on a large scale, for the simple reason that there were very few large whales to hunt. The Danish did hunt porpoises. The animals were driven to a sea strait with the help of boats where they were easy to catch and kill.
Other threats
In the 1960s and 1970s, the number of porpoises and bottlenosed dolphins declined sharply in the coastal water. One suspects that this has to do with pollution in the North Seawater and a decline in the availability of herring and other food sources. Porpoises have been increasing in number as winter guest along the Dutch coast in the past several years.
Protection
Internationally, the cetaceans fall under the Treaty of Bonn, which regulates the protection of migrating animal species. Cetaceans belong to the second category of that treaty; it is not threatened by extinction but it is vulnerable.
Dolphin rehabilitation
Porpoises and dolphins are much more difficult to care for than seals. If they wash ashore alive, their chances of survival are slight. Nevertheless, in the Marine Zoo in Hardewijk, a basin has been set up for caring for small cetaceans. The society SOS Dolphins trys to save dolphins as much as possible. Various centers along the coast, including Ecomare on Texel, have special equipment for the first care, after which the animals are transported to Hardewijk. If they succeed to save the animal, it is returned to the sea. In 1994, a white-beaked dolphin which had stranded on Texel was successfully rehabilitated in Hardewijk and released back into the North Sea.
Exceptional finds of cetaceans along the Dutch coast
| date | place and details |
| 14 July 1914 | Cuvier-dolphin (male beached in the Westerschelde) |
| 13 December 1925 | Dwarf sperm whale - Noordwijk aan Zee |
| 1997 | Black swordfish, IJmuiden, 2 animals |
| 1994-1996 | various bones of a grampus are fished up in the Southern North Sea |
| 1997 | Skull from a northern right whale was foundon Schouwen-Duiveland by school children during the Coastwatch investigation |
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Weblinks
For more information about cost-efficient diving in marine animals, see: http://www.utmsi.utexas.edu/staff/fuiman/diving/index.htm
Internation database on cetaceans:
http://home.planet.nl/~camphuys/Cetacea.html
A good German site about dolphins and other cetaceans, including dolphin sounds:
http://www.delphin-homepage.de/
The summaries of the contributions of the German serie 'Wal und Mensch' (also in English):
http://www.cetacea.de/
Names:
Dut: walvisachtigen
Eng: cetaceans (whales and dolphins)
Fren: cétacés (baleines et dauphins)
Ger: Walartige
Lat: Cetacea
Dan: Cetacean
