Sexual maturity is reached at approximately 8—10 years of age and females give birth every two to three years thereafter. The life expectancy of blue whales in not known, but it is likely that they live 80—90 years, perhaps even longer. Blue whales were hunted to the brink of extinction.
In excess of 10, animals were taken in the North Atlantic alone, and hundreds of thousands were taken in the Southern Ocean. The blue whale was protected worldwide in , but the species remains endangered today. There has been a notable increase in the number of reported sightings of this species in Svalbard; for example, in 63 observations were reported from coastal waters.
Undoubtedly, many of these sightings from various boats are reporting the same individuals. Skip to main content. Blue whale. Norwegian Polar Institute » Arter » Blue whale. Description The blue whale is the largest animal ever to have lived on earth. Blue whales are most commonly observed alone or as pairs. Vulnerable VU. Whales are an important part of the marine food chain and play a huge role in maintaining the health of our oceans.
While it may be considered an endangered species, the blue whale is truly international, occurring in all oceans except the Arctic, and enclosed seas of course. Before whaling there may have been as many as ,; today, it is one of the world's rarest species, with the population of blue whales numbering just 10,, Most biologists consider it among the most endangered of the great whales. Only one population, in the northeast Pacific off California, is showing real signs of recovery and it contains around 3, animals.
Their iron-rich poo is a really important source of nutrients in the marine food chain, promoting Southern Ocean productivity, which boosts fishery yields. These nutrients, particularly iron and nitrogen, are vital for phytoplankton, at the base of the food chain.
Because plankton help to remove carbon dioxide from the atmosphere, you could go as far as to say that blue whales are carbon neutral. However you calculate it, whales are fertiliing their feeding grounds and providing sufficient nutrients to sustain krill populations. Although there is debate surrounding the taxonomy of blue whales, there are five distinct subspecies: Antarctic blue whales in the Southern Ocean Balaenoptera musculus intermedia ; North Atlantic and North Pacific blue whales Balaenoptera musculus musculus ; Pygmy blue whales, found in the Southern Indian Ocean Balaenoptera musculus brevicauda ; Northern Indian Ocean Balaenoptera musculus indica and South Pacific Ocean Balaenoptera musculus unnamed species whales.
Climate change, ship strikes and entanglement in fishing gear are the primary threats faced by blue whales. Additional threats that could potentially affect whale populations include anthropogenic noise, habitat degradation, pollution and vessel disturbance. Noise pollution Blue whales use sound to find their partners and perhaps location of topographic features and prey. Man-made noise can potentially mask their vocalisations, throwing them off-course and disrupting both movements and breeding.
Potential sources of man-made underwater noise in Australian waters include seismic surveys for oil, gas and geophysical exploration; industrial development such as drilling, pile-driving, blasting and dredging ; gas processing and shipping. Increased shipping traffic Vessels can collide with whales or disrupt their behaviour.
Blue Whales Balaenoptera musculus The blue whale Balaenoptera musculus is a marine mammal belonging to the suborder of baleen whales called Mysticeti. Orca Whales. Humpback Whales.
Gray Whales. Finback Whales. Common Dolphins. Blue Whales. Reaching lengths of at least feet 33 meters and weights of tons tonnes , these animals are only slightly smaller than the United States Space Shuttle. Their incredible size is only possible because of their aquatic lifestyles and the buoyancy provided by seawater. On land, an animal as large as the blue whale would almost certainly be crushed under its own weight.
Interestingly, though they are enormous, blue whales are not predatory. They filter feed for tiny krill and are totally harmless to people other than through accidental collisions. This life history strategy is common among several large animals in the ocean, including the whale shark , the basking shark , and the other great whales. Like all whales, blue whales are mammals and give live birth to very large calves that they nurse for six or seven months.
0コメント