Tag: Population

Narrow-ridged (or East Asian) finless porpoise

Narrow ridged (east Asian) finless Porpoise

This species is native to the East China Sea, Yellow Sea, and the seas around Japan. The Yangtze finless was originally thought to be a subspecies of this porpoise, though further study showed its differences to be greater than that (hence it now being recognized as a separate species). The east asian finless porpoise is a subspecies of the narrow ridged finless porpoise (the above picture is one of these).

Growing to 2.27m at most, and 72kg, though most are smaller.

They generally stay in water 50m deep or less, and mostly stay close to shore (though not always – it has been spotted over 100km from land).

The biggest threat to them is habitat degradation and pollution. The population has fallen by 50% in the last 3 generations.

They have been kept in captivity in Japan, Indonesia and China. A total of 94 are thought to have been held. Unfortunately these do not live long, and of all of the pregnancies that have occurred in captivity, only 2 resulted in a love birth and this did not survive for long.

Harbour Porpoise

Harbour Porpoise

This is one of the smallest cetaceans, which spends the majority of its time in estuaries and harbours – though it will sometimes venture up rivers, and have been found 100km from the coast.

They get their name from an anglicized version of the french word Porpois. This in turn comes from a medieval Latin amalgamation of two word – these are porcus (pig) and Piscus (fish). I think that these names are rather unfair, but still.

Its range is the North Atlantic, North Pacific and the Black sea. The populations are not continuous and as such there is a series of sub-populations that are geographically limited.

They are thought to have a global population of around 700,000, the Baltic sea is the only one which is seriously endangered, and that is the Baltic sea population which is thought to be around 500. Others could become endangered if current trends continue such as the Black sea population which is currently estimated to number around 12,000.

They have to spend a great deal of time looking for food, as they need to eat 7-8% of their bodyweight each day.

Generally, they live 8-13 years although individuals have been recorded living to over 20.

Dalls Porpoise

Dall's Porpoise

Lying in its own genus of Phocoenoides, the dalls porpoise is found to the west of North America and the East of Asia. The largest porpoise species they can grow to 2.3m and 220kg. Living in fluid groups of 2-10, Males compete for females, and many will guard a single female during the breeding season, in order to be sure that any offspring is theirs.

Females give birth around once every 3 years, with pregnancy lasting 11-12 months. They often ride boats bow-ride, and even will do the same on bigger whales.

They are abundant, in their range, and have a population of around 1 million in the wild.

There is a range of different sub-populations, but given the size of the overall population it should be secure in the long-term. Of course the problem is that this could change fast.

Burmeister Porpoise

Bermeister Porpoise

First described by Hermann Burmister in 1865, they are thought to have a population that numbers at least in the 10,000s. Found from Peru in the Pacific to Brazil in the Atlantic, while usually found in shallow coastal waters, they have been located 1000m down.

Most photos of this species are of a dead individual. It is black which explains its other name – the black porpoise, though it is thought that they turn black after death and are dark grey beforehand. The underside is lighter, though this is common as it helps with camouflage against the light surface of the water. Usually 1.5m in length and with a weight of 50-75kg, they can be mistaken for the Chilean dolphin, which is a similar size. Their dorsal fin is more triangular and points back rather than up so should not be confused.

They are shy, usually moving away from boats at a high speed. Usually seen in pairs or alone. However, they have been seen in larger groups, with a group spotted off the coast of Chile numbering 50.

Eating Hake, Maceral and Anchovies, which are all species impacted greatly by el nino. Many of the marine mammals in the area starved or struggled until the fish returned.

Beluga Whale

Beluga Whale

Beluga whales are only found in the arctic and sub-arctic oceans. They are one of just 2 species in their family Monodontidae, and are unique in their genus of Delphinapterus. It is also known as the white whale, the sea canary and the Melon-head (though the melon-headed dolphin is a species of its own, so this name may cause some confusion.

Adaptions it has for the Arctic, include the fact that it is white in colour, allowing it to blend into the white world more effectively, and the fact it has no dorsal fin, which allows it to swim very close to the ice sheet above.

Growing up to 5.5m in length and up to 1600kg they are a pretty large dolphin. Generally, living in groups of around 10, in the summer, they group together in their hundreds or thousands.

The worlds population is thought to be around 200,000, Some populations move from the edge of the ice cap, into rivers in warmer areas, while others stay around the ice caps year round. Groups of people in both USA and Russia have hunted them for many centuries.

Hunting is not controlled, and as such the drop in population could happen quite fast. Russia and Greenland have killed enough to drop their local population significantly, though thankfully not Alaska or Canada.

They do also have their natural predators in both the killer whale and the Polar bear.

They are the most commonly kept cetaceans in the world, with around 300 in captivity. Japan, USA, Ukraine, Canada, China and Russia as well as a few more.

There are 22 populations around the world, these vary from 39,000 down to as little as 500. The total population is around 200,000. While this number is large, the number hunted is definitely not sustainable. There is also no care to distinguish the different populations, which suggests that sub-populations could be pushed to extinction without any care.

Below, you will find a clip from a bbc documentary which features this species. Below this, is a list of any mentions that the beluga whale has had on this site. Below this, I will list any opportunities to see this species in the wild. Click on list your wild place, to list yours. It takes just a few minutes, and costs nothing – we only charge a commission on any business we send your way.

Brydes whale

Brydes Whale

Brydes whale can refer to the species of whale, but it can also refer to the Brydes whale complex which includes 3 or 4 species (brydes whale, Edens whale, Omera whale (which is sometimes referred to as the Pygmy Brydes whale) and the Rice whale.

Worldwide population is around 90,000-100,000. As a result, the entire species is considered least concern. It is therefore essential to work out if the closely related species of whales, are subspecies or separate species.

Sei Whale

Sei Whale

The third largest after the blue and the fin whale, it is found in most of the worlds deep oceans, though it avoids the tropics and the polar regions. It can reach lengths of 19.5m and weights of 28 tonnes, it is capable of consuming 900kg of food in a day.

It can reach speeds of over 30 mph (50kmh) over short distances making it one of the fastest whales. During commercial whaling, around 250,000 were taken, and the population fell to between 7000 and 13,000. This has thankfully recovered to 80,000 but is clearly still not near its pre-whaling numbers.

Sei is the Norweigen word for the Pollark fish which appears off the coast at the same time of year, to feast on the plankton which is abundant at that time of year.

They generally migrate away from the poles to spend the winters in warmer waters.

Mass stranding events (over 300 dying at a time on occasion) happen from time to time, and while we are not sure what causes this, we think it is likely some sort of poisoning of their waters – such as a red tide. 

Humpback whale

Humpback whale

The humpback whale is a widely recognized species. Weighing around 40 tonnes, and measuring 14-17m. It is known for its habit of breaching (as above) which can be heard from miles away, and its incredibly complex song, which can last between 4 minutes and 33.

Their low sounds can be heard by whales 1000 miles away, and have been picked up by electronic sources far further away than that.

Whaling did horrific damage to this species, with their population falling to just 5000 in the 1960s. Thankfully, having been protected, the population is now around 135,000. Subspecies are more varied, with those in the northern hemisphere less secure. The least secure is the Arabian sea population, which is thought to be isolated for 70,000 years and there are only 80 that remain.

Threats to individual whales include entanglement in fishing gear, ocean noise and collisions with ships.

They are known to have hunting methods more complex than most baleen whales, including bubble netting which forces the fish into tighter shoals to then be taken in one mouthful.

Young are predated by orca in some parts of the world, and many carry scars from these encounters to the end of their lives.

 

Southern (Antarctic) Minke whale

Antarctic (Southern) Minke whale

Bizarrely, having been described in the 1850s it was not recognized as a separate species until the 1990s. Thankfully, largely ignored by whalers, it came out of the whaling age with a population that still numbered in the hundreds of thousands – with current estimates falling around half a million individuals.

The Antarctic and the Southern Minke whales are thought to have diverged around 4.7 million years ago. They are found throughout much of the Southern hemisphere.

They are the main prey item for type A killer whales, with multiple occasions this hunt having been watched. There has been a recorded occasion when a group of 10 type B killer whales also killed one of these whales.

Grey whale

A grey whale breaching: An incredible sight, and the sound travels a very long way in water

Grey whale

The gray whale (other names include grey whale, gray back whale, Pacific gray whale, Korean gray whale, or California gray whale), is a baleen whale that migrates between feeding and breeding grounds yearly. They can reach 14m in length and 41 tonnes. It is found in North pacific – with the Northeast Pacific (American population) and the Northwest Pacific (Asian population) that is endangered. The northern population has been extinct for a long time.

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