New discovery of two separate subspecies of short- finned pilot whale in the Pacific Ocean.

Emer Keaveney, M.Sc., Marine Biology. • 3 June 2019

A new study published today in Molecular Ecology has confirmed the existence of the "Naisa" form of short-finned pilot whale, a subspecies long described by Japanese whalers and scientists in the South Pacific. Short-finned pilot whales have a large distribution, ranging over a large area of the world's oceans, with habitats in the Pacific, North Atlantic and Indian oceans. Despite their broad range, until today, short-finned pilot whale was thought to be one single species.

Short-finned pilot whale ( Globicephala macrorhynchus ). Photo: Wikicommons.

Pilot whales are large aquatic mammals belonging to the Globicephala genus. The genus consists of 2 extant species, the short-finned pilot whale ( Globicephala macrorhynchus ) and the long-finned pilot whale ( Globicephala melas ). Between these two species, the animals are found across the world's oceans. Long finned pilot whales generally prefer cold deep water with some populations permanently remaining offshore. They may move into inshore areas in search of food. The short finned whales in comparison, prefer warm tropical and sub-tropical waters with populations living around the outer boundaries of continental shelves. But, individuals have been reported to move towards the coastal areas, sometimes, far enough onshore to become stranded.

Pilot whales are closely related to the extinct blunt-snouted dolphins. Extant relatives of the whale include the Risso’s dolphin, false killer whale, melon-headed whale and the pygmy killer whale. Pilot whales are often referred to as “Blackfish” along with a number of other species belonging to the Dolphin family.

There are two separate sub-species of long-finned pilot whales: the Southern hemisphere- where they occupy a circumpolar distribution in cold sub-Antarctic waters; and in the Northern hemisphere their range is restricted to the north Atlantic Ocean, the North Sea and the western Mediterranean, from the Azores to Greenland. They favour deep waters, although their seasonal movements may reflect prey distribution. It is long finned pilot whale which we find in Irish waters.

Short-finned pilot whales, in comparison are distributed in the tropical and warm temperate waters of the Atlantic, Pacific and Indian Oceans. Off the southwest coasts of several Canary Islands (especially Tenerife and La Gomera), east off Japan, off Hawaii, in waters off the Azores, in the Monterey Bay, California, and Madeira; nomadic as well as resident groups are frequently sighted.

There is ample opportunity to see short-finned pilot whale from shore in many places which has led to year-round research activities such as photo ID studies, a non-invasive method of identifying individual animals ( read more here..), and the development of whale watching activities (whale watching near you..). Data obtained from fossil findings, stranding events, incidental catches and opportunistic surveys showed that short-finned pilot whales were encountered off French Polynesia, the British Columbia coast, off Peru, Pacific coast of Mexico and Costa Rica, Taiwan (for the Pacific), Brazil, U.S.A., in the Caribbean, Angola, Senegal (for the Atlantic), Indonesia, Malasia, Seychelles, Mozambique, Sri Lanka, and India (for the Indian Ocean).

In 1760 two different types of short-finned pilot whales were first described by a Japanese naturalist called Yamase. Short-finned pilot whales with square-shaped heads in southern Japan were called the “Naisa form” and the round-head variety in northern Japan the “Shiho form”.

Now a new study by lead researcher Amy Van Cise, a postdoctoral scholar at the Woods Hole Oceanographic Institution in Massachusetts has proven the 250 year old theory correct using the latest DNA tests. According to the study published in Molecular Ecology , Dr Cise and her team analysed 725 samples collected by researchers from all over the world and tested their mitochondrial DNA. By comparing this information with known whales and dolphins, researchers could identify that the groups were subspecies, despite the fact the whales are not separated by a continental barrier and what separates them is just the vast expanse of the eastern Pacific Ocean.


Different subspecies of whale is expected in each ocean basin—the Atlantic, Indian, and Pacific. Researchers would consider that to be common. However, what Dr Van Cise found was that short-finned pilot whales in the Atlantic are the same sub-species as those living in the Indian Ocean and western Pacific. Short-finned pilot whales, living off northern Japan and the eastern Pacific however, appeared to be one distinct subspecies.

This new study provides a unique insight into the factors that drove the evolution and speciation of pilot whales in the Southern Hemisphere - , that it may have been in-fact an "ocean deseert" and not physical land barriers that were important.

A taxonomy board is to review the proposal and decide whether these subspecies should be officially given different classifications.

© Ocean Research & Conservation Ireland (ORCireland) and www.orcireland.ie , est. 2017. Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Ocean Research & Conservation Ireland and www.orcireland.ie with appropriate and specific direction to the original content.

Reference:

Amy M. Van Cise, Robin W. Baird, Charles Scott Baker, Salvatore Cerchio, Diane Claridge, Russell Fielding, Brittany Hancock‐Hanser, Jacobo Marrero, Karen K. Martien, Antonio A. Mignucci‐Giannoni, Erin M. Oleson, Marc Oremus, M. Michael Poole, Patricia E. Rosel, Barbara L. Taylor, Phillip A. Morin. Oceanographic barriers, divergence, and admixture: Phylogeography and taxonomy of two putative subspecies of short‐finned pilot whale . Molecular Ecology , 2019; DOI: 10.1111/mec.15107

SHARE THIS ARTICLE

by ORCA SciComm Team 5 September 2022
Bird Flu is a serious threat to Irish Gannet Colonies. ORCA SCI-COMM TEAM | 04 September 2022 ORCA Ireland are deeply concerned about the severe epidemic of bird flu of the H5N1 strain, which is highly pathogenic in cases of pelagic seabirds and has now hit seabirds in Irish waters. According to top scientists at the University College Cork (UCC), avian influenza has now reached Irish Gannet colonies. Recent reports from Irish scientists and members of the public have indicated a huge increase in the numbers of dead northern gannets off the Irish coasts. These increases in seabird deaths may be linked to the Highly Pathogenic Avian Influenza (H5N1).
by ORCA SciComm Team 14 July 2022
PCB Pollution Threatens Global Killer whale ( Orcinus orca ) Populations. ORCA SciComm Team | 14th July 2022 Global killer whale population are predicted to collapse due to pollution with polychlorinated biphenyls (PCBs). A scientific report which used individual-based models combined with globally available data on PCB concentrations found that PCB-mediated effects on reproduction and immune function threaten the longterm viability of >50% of the world’s killer whale populations.
by ORCA SciComm Team 29 April 2022
Russian Navy Trained Dolphins Deployed in Crimea ORCA SciComm Team | 29th April 2022 Russian Navy Trained Dolphins may have been deployed in Crimea, with two sea pens having been spotted at one of their bases in satellite imagery since the start of the Ukraine invasion in February, according to the US Naval Institute.
by Danielle Brennan | Communications Officer 15 March 2022
FEMALE KILLER WHALES FACE GREATER IMPACT FROM NOISE POLLUTION Danielle Brennan | Communications Officer | 15th March 2022
by ORCA SciComm Team 1 March 2022
A solitary common dolphin can speak porpoise language! ORCA SciComm Team | 1st of March 2022 A new paper published in “ Bioacoustics - The International Journal of animal sound and its Recording ” has detailed how a solitary common dolphin in Scotland has learned to speak porpoise language!
by ORCA SciComm Team 4 February 2022
Iceland to end whaling in 2024 with drop in demand for whale meat. ORCA SciComm Team | 4th February 2022 Iceland have announced an end to commercial whale hunts in 2024, after a government minister commented there was "little justification for the practice". Whaling in Iceland is no longer profitable, due to a decrease in the consumption of whale meat and since Japan re-commenced whaling operations after a three decade hiatus in 2019.
by ORCA SciComm Team 25 January 2022
RUSSIAN MILITARY TESTS THREATEN WHALES IN IRISH WATERS ORCA SciComm Team | 25th of January 2022
by ORCA SciComm Team 11 December 2021
Shell Oil & Gas Seismic Surveys Threaten Whales off South Africa ORCA SCI-COMM TEAM | 11th of December 2021 Across the globe there is public outrage due to the planned seismic surveys to search for oil and gas deposits off South Africa's Wild Coast by energy company Shell. Environmental NGO's, Human Rights Organisations and local fishing communities are trying to stop the seismic surveys through litigation, due to the harmful impact seismic surveys can have on marine wildlife. South Africa is home to 37 species of whales and dolphins, but these anthropogenic activities threaten the survival of wild whales off Africa's south coast. Let's dive deeper to investigate what seismic surveys are and how they can harm whales!
by ORCA SciComm Team 9 December 2021
How to Create a Sustainable Wardrobe! ORCA SciComm Team - 9th December '21 The idea of creating a sustainable or ethical wardrobe from scratch is, without a doubt a challenging task. You may not be able to wear the brands you are used to, limiting your choices in terms of trends, not to mention having to spend a little more than you would normally. All of these are valid concerns, but creating a sustainable wardrobe isn't as hard as you may think. Read on to find out tips and tricks to help you transition from a "fast fashion" foe to a "slow fashion" soul sista!
by ORCA SciComm Team 4 December 2021
Russian “Whale Jail” finally Abolished. ORCA SciComm Team | 3rd of December 2021 The incommodious confined pens in Russia’s infamous “Whale Jail” have finally been abolished to ensure marine mammals will not be held in these captive facilities in the future!
Show More