Shepherd's beaked whale

Shepherd's beaked whale (Tasmacetus shepherdi), also commonly called Tasman's beaked whale or simply the Tasman whale, is a cetacean of the family Ziphiidae and the only species in the genus Tasmacetus. The whale has not been studied extensively. Only four confirmed at sea sightings have been made and 42 strandings recorded (as of 2006). It was first known to science in 1937, being named by W. R. B. Oliver after George Shepherd, curator of the Wanganui Museum, who collected the type specimen near Ohawe on the south Taranaki coast of New Zealand's North Island, in 1933.<ref>Te Ara Encyclopedia - Beaked whales – George Shepherd</ref><ref name=audubon>Template:Cite book</ref>

Description

File:Tasmacetus shepherdi, Inaccessible Island, Tristan da Cunha, January 27, 2017.png

First underwater sighting of live Shepherd's beaked whales, near Inaccessible Island, Tristan da Cunha, January 2017.

Adults can reach lengths of Template:Convert to Template:Convert and weigh about 2.32 to 3.48 tons. At birth they may be about Template:Convert long.

They are robust and large-bodied for beaked whales, having a bluff melon and a long, dolphin-like beak.<ref name=Shirihai>Template:Cite book</ref>

It is the only species of ziphiid with a full set of functional teeth (17 to 27 pairs in both the upper and lower jaws).<ref name=audubon/> Adult males also have a pair of tusks at the tip of the lower jaw.

They are dark brown dorsally and cream-colored ventrally, with a pale band extending up from the flipper and another pale area extending as a swathe on the posterior flank. The tall, falcate dorsal fin is set about two-thirds the way along the back.<ref name=Shirihai/>

Population and distribution

Sightings and stranding records indicate that the species has a circumpolar distribution in southern hemisphere.<ref>Jared R. Towers, Paul Tixier, 2022, Indian Ocean Sighting of Shepherd’s Beaked Whale (Tasmacetus shepherdi) Helps Confirm Circumpolar Distribution in Southern Hemisphere, Aquatic Mammals, 48(5), pp.462-467</ref> No population estimates exist for Shepherd's beaked whale. As of 2006, there have been about 42 stranding records of the species from New Zealand (including the Chatham Islands, 24), Argentina (7), Tristan da Cunha (6), Australia (3), and the Juan Fernández Islands (2). The northernmost record was at Shark Bay in Western Australia in 2008.<ref>Carly Holyoake, Dave Holley, Peter B. S. Spencer, Chandra Salgado Kent, Doug Coughran, Lars Bejder, 2013, Northernmost record of Shepherd's beaked whale (Tasmacetus shepherdi) - A morphological and genetic description from a stranding from Shark Bay, Western Australia, Pacific Conservation Biology, 19 (2), pp.169-174, DOI:10.1071/PC130169</ref> There have been five unconfirmed sightings (mostly from New Zealand), as well as a "probable" sighting near Shag Rocks and four confirmed sightings—the first two confirmed sightings occurred in 1985, within a few minutes of each other, off the Tristan da Cunha group (first sighting at Template:Coord); the third in 2002 near Gough Island (Template:Coord); and the fourth in 2004 south of Tasmania (Template:Coord).<ref name=Pitman2006>Template:Cite journal</ref> In January 2012, a group of up to a dozen of this species were photographed and filmed by the Australian Antarctic Division south of Portland, Victoria.<ref>Australian Antarctic Program, 2012, Whale trackers make rare sighting, Australian Antarctic Division, Retrieved on August 07, 2022</ref>

Multiple sightings of the species have been reported from Otago submarine canyons off Otago coast, New Zealand. Sightings have been recorded throughout the year with vocalization recordings, suggesting regular presences there.<ref name=MacLean/> These include at least two sightings in 2016 which were the first confirmed sightings within New Zealand waters,<ref>John Gibb, 2016, Sighting of beaked whale a first, Otago Daily Times, Retrieved on August 07, 2022</ref> followed by four sightings in 2017,<ref>Vaughan Elder, 2017, Population of whales off Dunedin coast significant, study finds, The Otago Daily Times, Retrieved on September 02, 2021</ref><ref>New Zealand Whale and Dolphin Trust, 2017, December 14th, 2017 on Facebook, Retrieved on September 13, 2022</ref> one or more sighting(s) in 2018,<ref>Steve Wood, 2018, Otago Canyon Pelagic - Sept 29th., BirdingNZ, Retrieved on August 07, 2022</ref><ref>New Zealand Whale and Dolphin Trust, 2019, June 29th, 2019 on Facebook, Retrieved on September 13, 2022</ref> one sighting in 2019,<ref>David Donnelly, Marine Research, 2019, November 30th, 2019 on Facebook, Retrieved on September 13, 2022</ref> four or five sightings in 2021,<ref>oscarkokako, 2021, Shepherd's beaked whale (Tasmacetus shepherdi), iNaturalist, Retrieved on August 07, 2022</ref><ref>Oscar Thomas, 2021, Moeraki Pelagics to Otago Canyons / Saturday 3rd and Sunday 4th July 2021, BirdingNZ, Retrieved on August 07, 2022</ref><ref>Project Jonah New Zealand, 2021, October 31st, 2021 on Instagram, Retrieved on September 13, 2022</ref><ref>Warwick Allen, Bobby Phuong, 2021, October 21, 2021 on Instagram, Retrieved on September 13, 2022</ref><ref>Peter Langlands, 2021, December 30th, 2021 on Facebook, Retrieved on September 13, 2022</ref> five sightings in 2022 including a pod of 15-20 animals.<ref name=MacLean>Hamish MacLean, 2022, Rare whales seen, vocalisation recorded, The Otago Daily Times, Retrieved on February 24, 2022</ref><ref>adamduchac, 2022, Shepherd's beaked whale (Tasmacetus shepherdi), iNaturalist, Retrieved on August 07, 2022</ref><ref>Annie Ching, 2022, January 13th, 2022 on Facebook, Retrieved on September 13, 2022</ref><ref>Oscar Thomas, 2022, Moeraki Pelagics Nov 12/13 Report, BirdingNZ, Retrieved on November 15, 2022</ref>

There have been additional sightings from other parts of New Zealand, such as off Gisborne,<ref>Gisborne Herald, 2019, Pod of rare whales filmed off Gisborne, Retrieved on August 07, 2022</ref> several sightings off Kaikōura,<ref>The New Zealand Herald, 2017, Rare Shepherd's beaked whales spotted off Kaikoura coast, Retrieved on August 07, 2022</ref><ref>Whale Watch Kaikoura, 2018, The Rarest of the World's Whales - Spotted Twice whilst Whale Watching, Retrieved on August 07, 2022</ref><ref>Alan Granville, 2019, 'Extraordinary': Exceptionally rare whale visits Kaikōura, Stuff, Retrieved on August 07, 2022</ref> off Fiordland,<ref>hannahwilllliams, 2022, Shepherd's beaked whale (Tasmacetus shepherdi), iNaturalist, Retrieved on August 07, 2022</ref> Taranaki,<ref>Saltwater iv, 2017, Very Rare Shepherd's Beaked Whale - Tasmacetus shepherdi _ Taranaki New Zealand on Youtube, Retrieved on September 13, 2022</ref> and so on.

Behaviour

Four of the confirmed sightings of this species involved three to six individuals (one group included a calf) in waters from Template:Convert to Template:Convert deep, while a 2012 sighting involved as many as ten to twelve individuals. The animals surfaced several times, before arching to dive. Some were observed to come to the surface at a steep angle like many other ziphiids, raising their head and beaks out of the water.<ref name=Pitman2006/> The Shepherd's beaked whale's blow could be observed with the naked eye at a distance of up to 1,000 metres, within a bushy plume that is relatively tall for a ziphiid varying from 1 to 2 metres in height <ref>Template:Cite journal</ref>

The species is seldom seen because of its deep, offshore distribution in waters where sighting conditions can be difficult (the "Roaring Forties" and "Furious Fifties").<ref name=Pitman2006/>

Research done on a stranded individual's stomach has indicated that Shepherd's beaked whales eat both fish and squid, as opposed to most beaked whales which only eat cephalopods.<ref>Template:Cite journal</ref>

Conservation

There are no reports of this species being hunted or killed accidentally by humans. Shepherd's beaked whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU).<ref>Official webpage of the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region</ref>

Taxonomy

Recent molecular evidence suggests that this species diverged after the most basal extant ziphiid genus, Berardius, and prior to Ziphius<ref name='mcgowen2020phylores'>Template:Cite journal</ref>

Popular culture

The species was featured on a 45p commemorative stamp issued by Tristan da Cunha in 2019 as part of a set celebrating different species of whale.<ref>Template:Cite news</ref>

See also

• List of cetaceans

Sources

1. Shepherd's beaked whale in the Encyclopedia of Marine Mammals Thomas A. Jefferson, 1998. Template:ISBN
2. Whales, Dolphins and Porpoises Carwardine, 1995. Template:ISBN