Everything about The Dusky Dolphin totally explained
The
Dusky Dolphin (
Lagenorhynchus obscurus) is a highly gregarious and acrobatic
dolphin found in coastal waters in the
Southern Hemisphere. It was first identified by
John Edward Gray in
1828. It is very closely
genetically related to the
Pacific White-sided Dolphin, but current scientific consensus is that they're distinct species.
Though the Dusky and Pacific White-sided Dolphins are traditionally placed in the genus
Lagenorhynchus, recent
molecular analyses indicate that they're more closely related to the dolphins of the genus
Cephalorhynchus. If true, this would mean that these two species must either be transferred to
Cephalorhynchus or be given a new genus of their own.
Physical description
The Dusky Dolphin is small to medium in length in comparison with other species in the family. There is significant variation in size among the different population areas. The largest Duskies have been encountered off Peru, where they're up to 210 cm in length and 100 kg in mass. The back of the dolphin is dark grey or black and
dorsal fin is distinctively two-toned—the leading edge matches the back in colour, but the trailing edge is a much lighter greyish white. Duskies have a long, light grey patch on their foreside leading to a short, dark grey beak. The throat and belly are white. There are two blazes of white colour running back on the body from the dorsal fin to the tail. Right between the white areas remains a characteristic thorn-shaped patch of dark colour, by which the species can easily be recognized. Aside from that, Dusky Dolphins may be confused with other members of their
genus when observed at sea.
Population and distribution
The population of Dusky Dolphins is unknown, but authorities don't fear for the survival of the species at the moment. The Dusky Dolphin is distributed in coastal waters of
Chile,
Argentina and the Falkland Islands,
Namibia and the west coast of
South Africa and all around
New Zealand. There may also be resident populations off
Tasmania and
New South Wales and several small islands in the
South Atlantic and
Indian Oceans. An aerial survey off
Patagonia in the mid-
1990s indicated that there was a local population in excess of 7,000 individuals. Duskies can move over great distances (one individual had a confirmed range of 780
nautical miles) (1,440 km). However it isn't believed that they follow a migatory pattern.
Conservation and dolphin-watching
Outside
Peruvian coastal waters, the main danger to Dusky Dolphins from humans is the accidental catching of individuals by fishing trawls. In the mid-
1980s around 400–600 animals were killed annually off Patagonia due to individuals becoming trapped in nets. Rates appear to have declined since then, due to tighter regulations on the fishing industry. However, in Peruvian waters, in addition to accidental catches, there's continuing deliberate catching via nets and harpoons. The number of animals killed each year in this area runs into the thousands and is a cause of concern for conservationists.
On account of their highly acrobatic displays and movements in large groups called pods, Dusky Dolphins are firm favourites with
dolphin-watching enthusiasts. Several boat operators from
Kaikoura, on
New Zealand South Island are either dedicated to watching Duskies or watch them in combination with tours aimed at watching
Sperm Whales.
Pictures
Image:Lagenorhynchus obscurus.jpg
Image:Lagenorhynchus obscurus2.jpg
Image:IMG 7082.JPG
Image:duskyd.jpg
Further Information
Get more info on 'Dusky Dolphin'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://dusky_dolphin.totallyexplained.com">Dusky Dolphin Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |