Fin whale
| Fin whale | ||||||||||||
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Blowing fin whale off Greenland |
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| Balaenoptera physalus | ||||||||||||
| ( Linnaeus , 1758) |
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The fin whale ( Balaenoptera physalus ) is a species of the furrow whale and the closest relative of the blue whale .
features
Adult males are 18 to 24 meters long in the northern hemisphere and 20 to 27 meters in the southern hemisphere. Females are slightly larger than males, but about the same weight, with around 40 to 70 tons. The fin whale is much slimmer and lighter than a blue whale of the same length and even weighs less than some shorter whale species such as bowhead whale or sperm whale .
The back of fin whales is dark gray to black brown; the belly and the underside of the Flipper and Fluke are colored white. The species can be reliably identified by the asymmetrical color distribution on the front part of the body: the lower jaw is white on the right, but dark on the left. This coloring extends to the beards as well. The inside of the mouth and tongue are reversed in color. A few dozen throat furrows extend from the lower jaw to the navel.
distribution
Fin whales are common in all oceans. Coastal regions are avoided. For the winter months they migrate to subtropical, moderately warm waters to mate and give birth to their young. In summer they migrate to the colder waters of the Arctic or Antarctic to eat. Since the seasons are opposite to each other in the hemispheres, southern and northern populations never meet at the equator. Some zoologists see them as separate subspecies : the northern fin whale ( B. p. Physalus ) and the southern fin whale ( B. p. Quoyi ). The southern one is about 10% larger than the northern one.
Way of life
Fin whales are mostly found alone, but also live in groups of around six animals. Larger groups were also spotted regionally. The fin whale swims faster and dives deeper than most other large whales . It is up to 50 km / h and regularly reaches diving depths of well over 200 meters. He stays under water for about fifteen minutes. The food consists almost entirely of krill , which is sifted through the beards. Smaller schooling fish are also accepted. The school is circled at high speed, rounded up into a dense pile, then the baleen whale lies on its side to devour the fish. The fin whale takes in between 60 and 82 tons of seawater at once and doubles its body volume. Up to two tons of food are consumed every day.
Reproduction and development
The calf is born after a twelve-month gestation period in late autumn after arriving in the winter quarters. It is about six and a half meters long and weighs 1,800 kilograms. It is suckled for about six months until it reaches a length of ten to twelve meters. Fin whales reach sexual maturity before they are fully grown, around six to ten years of age.
Whaling and Protection
Due to its speed and its ability to live in the open sea, the fin whale had no hunting enemies for a long time. It wasn't until the late 19th century that humans developed ways of hunting fin whales. Initially, the blue whale remained more attractive as prey. It was only when this was almost extinct that fin whales were hunted on a large scale. In 1937/38, over 28,000 fin whales were captured in the Southern Ocean. The whaling went into the late 1960s continued unabated until the stocks virtually looted were. In 1982, the International Whaling Commission (IWC) agreed to stop commercial fin whale fishing in 1986 until the stocks recovered. After the Icelandic government decided in 2006 to allow commercial whaling again, shortly thereafter, on October 22, 2006, the first fin whale hunted was landed.
The original population is estimated to be around 400,000 southern and 70,000 northern fin whales. Its excessive exploitation had pushed the population below 5000. Fin whales are much more common than the blue whale, but they are also an endangered species . The American Cetacean Society estimates that there will be around 15,000 fin whales in the southern hemisphere and 40,000 in the northern hemisphere in 2003.
relationship
Fin whales and blue whales are closely related. Investigation of mitochondrial DNA has shown that fin whales and blue whales are able to produce hybrids , although the lines of evolution of the two species have been separate for at least five million years. Occasionally there are crosses between the two species. Female hybrids can even be fertile. The similarities in the karyotype help reduce incompatibilities in meiosis and increase the likelihood of fertility.
Life expectancy
The maximum age of the fin whale is over a hundred years. Based on the chemical analysis of the amino acids in the eye lens of a 17-meter-long and 24-ton fin whale that stranded in the Danish Vejlefjord in summer 2010 , specialists determined an age of 130 to 140 years. The animal suffered from osteoarthritis due to its old age . The skeleton is to be exhibited in the Natural History Museum in Copenhagen in the future.
Sightings of live specimens and finds of carcasses
Even if the fin whale is usually a inhabitant of larger seas, it is occasionally found in the North and Baltic Seas , often as a dead find. In the summer of 2003, for example, a 15-meter-long fin whale stayed in the Kiel Fjord for several days . In October 2003 and July 2007, a dead fin whale was retrieved from the port of Hamburg .
In July 2005, a dead fin whale was discovered in the Baltic Sea near the island of Rügen . The carcass was towed to Stralsund on July 11, 2005 and brought ashore with two floating cranes in the Nautineum there on the Dänholm and examined, measured and prepared on site. This whale, a sexually mature male specimen, was 17.1 meters long, weighed about 40 tons, and was estimated to be about 10 to 15 years old. It was the largest fin whale found so far off the coast of Mecklenburg-Western Pomerania.
On January 14, 2006, another fin whale carcass was found in a bay off Wismar in the Baltic Sea. The find is of particular importance to the scientists, because whale carcasses were usually only found in the Baltic Sea in summer and were then already very bloated and decayed . That leads u. a. to the fact that the forest representations are not always exact. The animal that could no longer find the exit to the ocean has apparently starved to death. His skeleton is being kept so that it can later be exhibited in a new building at the Stralsund Marine Museum , the Ozeaneum . Because of the ice, the carcass could not be brought to the nautineum by water. The environmental organization Greenpeace offered to take over the transport free of charge if they could have the carcass for a few hours for their own surveying purposes; with the dimensions they want to make an inflatable whale model in original size. Instead, Greenpeace activists transported this fin whale to Berlin on January 18, 2006 to demonstrate against whaling in Japan in front of the Japanese embassy. According to the director of the Maritime Museum, Benke, this action did not harm the carcass thanks to the low outside temperatures.
On August 16, 2006, a fin whale was spotted again in the Flensburg Fjord , which the water police named "Henry". Between March 14 and 25, 2007, a fin whale was repeatedly observed in the Flensburg Fjord, particularly in the water life bay and off Sonwik . In Stralsund maritime museum, as well as in Budapest Natural History Museum are prepared skeletons of fin whales issued.
In March 2014, a dead fin whale washed up on the Canary Island of Fuerteventura . The carcass was in very good condition at the time it was found. The animal was examined by the University of Las Palmas in collaboration with experts from the Society for Marine Mammals in the Canary Islands. The skeleton of the 20 meter long fin whale is also to be prepared and exhibited.
On May 3, 2014, a 10 to 12 meter long fin whale was seen and photographed several times in the Gulf of Trieste .
According to a report in the Berliner Zeitung , on August 7, 2015, a 17-meter-long and 23-ton fin whale was sighted by Lithuanian fishermen off Klaipėda . Possibly it was this animal that a few days later was washed up dead in the Gdańsk Bay .
On April 25, 2017, about 15 nautical miles off the coast of Tossa de Mar on the Spanish Mediterranean coast, a carcass of a fin whale about 24 meters long was found. The bloated carcass suggests that the animal probably died several days earlier.
On August 20, 2017, a 19-meter-long carcass of a female fin whale washed up on the beach on the North Sea island of Texel . The carcass was already in an advanced state of decomposition. It is believed that the animal died as a result of a collision with a ship.
literature
- Mark Carwardine : Whales and Dolphins . Delius Klasing, 1996 (high quality guide).
- Ralf Kiefner: whales and dolphins worldwide . Year Top Special Verlag, 2002 (guide to the magazine “tauchen”, very detailed).
- Jochen Niethammer, Franz Krapp (Hrsg.): Handbook of mammals in Europe. Volume 6: marine mammals, Tel 1A: whales and dolphins 1 . Aula-Verlag, Wiesbaden 1994 (very detailed textbook).
- RR Reeves, BS Stewart, PJ Clapham, JA Powell: Sea Mammals of the World. A Complete Guide to Whales, Dolphins, Seals, Sea Lions and Sea Cows. Black, London 2002, ISBN 0-7136-6334-0 (guide with numerous pictures).
- M. Würtz, N. Repetto: Underwater world: Dolphins and Whales . White Star Guides, 2003, ISBN 88-8095-943-3 (identification book).
Web links
- Balaenoptera physalus inthe IUCN Red List of Threatened Species 2013.2. Posted by: SB Reilly, JL Bannister, PB Best, M. Brown, RL Brownell Jr., DS Butterworth, PJ Clapham, J. Cooke, GP Donovan, J. Urbán, AN Zerbini, 2008. Retrieved December 29, 2013. .
- American Cetacean Society Fact Sheet - Fin Whale .
- Current whale population estimates from the International Whaling Commission IWC.
Individual evidence
- ↑ Groß-Maul , sueddeutsche.de, November 28, 2007
- ↑ Ú. Árnason, A. Gullberg: Comparison between the complete mtDNA sequences of the blue and the fin whale, two species that can hybridize in nature. In: Journal of Molecular Evolution , (1993), 37 (4): 312-322.
- ↑ M. Bérubé, A. Aguilar: A new hybrid between a blue whlae, "Balaenoptera Musculus", and a fin whale, "B. Physalus ": frequency and implications of hybridization . In: Marine Mammal Science , (2006), 14 (1): 82-98.
- ↑ Klaus Barthelmess: About een mogelijke hybride tussen een Gewone en een Blauwe Vinvis. In: Marswin: Tijdschrift uitgegeven door de Vlaamse Vereniging voor de Bestudering van de Zeezoogdieren , Vol. 8, No. 1, 1987, pp. 9-12. Archive link ( Memento of the original from February 25, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Spiegel online: Record-breaking: 140-year-old whale stranded in Denmark , November 2, 2010.
- ↑ Stern: Report on the whale in the Kiel Fjord ( Memento of the original from October 12, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved July 23, 2013.
- ↑ Report on the whale off Rügen. In: Der Spiegel , accessed on July 23, 2013.
- ^ Report on the fin whale "Henry". In: Der Tagesspiegel , accessed on July 23, 2013.
- ↑ Tenerife News: Report on the whale find off Fuerteventura , accessed on March 13, 2014.
- ^ In: Berliner Zeitung , August 27, 2015.
- ^ Report on the stranding of a dead fin whale in Poland
- ↑ [1]
- ↑ [2]
- ↑ Gewone vinvis aangespoeld | Ecomare Texel . In: Ecomare . ( ecomare.nl [accessed on August 22, 2017]).
