Featured Research

from universities, journals, and other organizations

Killer whale genetics: Redefining stock structure in a marine top predator

Date:
July 11, 2013
Source:
American Genetic Association
Summary:
By collecting 462 skin samples from both resident and transient wild killer whales in the northern North Pacific and characterizing individual genetic variability using two different genetic markers (mitochondrial DNA and nuclear microsatellites), scientists have discovered further subdivision within the whale stocks than was previously believed. In fact, the evidence is so strong that the researchers believe it's time to revise the killer whale stocks in the region.

Recent research sheds light on stock structure of these apex predators in the northern North Pacific Ocean, with important implications for management.
Credit: Km M. Parsons, National Marine Mammal Laboratory, NOAA Fisheries

Found in every ocean around the world, killer whales are a force to be reckoned with globally. Their remarkable social bonds and sophisticated hunting techniques make them top predators in their salty domain. For many years, it was assumed that these clever, highly mobile whales bred with each other freely in the seemingly homogeneous ocean. As our understanding of the oceans' complexity has grown, and dedicated researchers have peered ever deeper into the world of killer whales, it has become clear that the truth is far more nuanced.

Related Articles


As the agency responsible for conserving and managing killer whales in U.S. waters, the National Oceanic and Atmospheric Administration (NOAA) faces a major challenge -- it must identify orca subpopulations, understand their needs, and develop effective and sometimes unique ways to manage them. Figuring out the patterns of similarity and relatedness coded in the whales' DNA also gives managers important insights into how these subpopulations arose, what factors shaped them, and what drove divergence in the species complex. This work has implications beyond identifying the boundaries of whale stocks. It is fundamental for evaluating the status of killer whale populations.

Recent studies have shown that distinct groups of killer whales gather in the same place seasonally. Previously, scientists didn't know whether this was attributable to feeding or mating patterns. Now, genetic evidence and observations of individual whales have shown that these whales exhibit low levels of "gene flow" -- breeding among subpopulations. A new paper by NOAA scientists available via Open Access in the Journal of Heredity sheds light on these principles at work among killer whales in Alaska and the northern North Pacific Ocean.

Uncertainty about the population structure and a lack of data for the far western reaches of the North Pacific have led to very broad stock designations for killer whales in the waters of the western Gulf of Alaska, Aleutian Islands, Bering Sea, and Russia. Currently, fish-eating "resident" killer whales in the far North Pacific are considered a single stock that ranges from southeast Alaska through the Aleutian Islands and Bering Sea. Bigg's killer whales (formerly known as "transients") are currently managed as two stocks with overlapping ranges -- the "Aleutian and western" stock (Gulf of Alaska, Aleutian Islands, and Bering Sea) and the much smaller "AT1" stock which appears to range primarily throughout Prince William Sound and the Kenai Fjords.

By collecting 462 skin samples from both resident and transient wild killer whales and characterizing individual genetic variability using two different genetic markers (mitochondrial DNA and nuclear microsatellites), NOAA scientist Kim Parsons and her research partners discovered further subdivision within the whale stocks. In fact, the evidence is so strong that Parsons and her colleagues believe it's time to revise the killer whale stocks in the region. Genetic tests also indicated a lack of breeding between the two killer whale types highlighting the distinctness of the sympatric Bigg's and resident killer whales on a local scale. This finding corroborates a 2010 global genetic study of killer whales1 and what many marine scientists suspected, based on years of studying wild orcas by tracking their movements and comparing their vocalizations, preferred prey, and social structure. Though much work remains to be done, powerful genetic tools have given us another vital piece of the puzzle.


Story Source:

The above story is based on materials provided by American Genetic Association. Note: Materials may be edited for content and length.


Journal Reference:

  1. Kim M. Parsons, John W. Durban, Alexander M. Burdin, Vladimir N. Burkanov, Robert L. Pitman, Jay Barlow, Lance G. Barrett-Lennard, Richard G. LeDuc, Kelly M. Robertson, Craig O. Matkin, and Paul R. Wade. Geographic Patterns of Genetic Differentiation among Killer Whales in the Northern North Pacific. Journal of Heredity, 2013; DOI: 10.1093/jhered/est037

Cite This Page:

American Genetic Association. "Killer whale genetics: Redefining stock structure in a marine top predator." ScienceDaily. ScienceDaily, 11 July 2013. <www.sciencedaily.com/releases/2013/07/130711135310.htm>.
American Genetic Association. (2013, July 11). Killer whale genetics: Redefining stock structure in a marine top predator. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2013/07/130711135310.htm
American Genetic Association. "Killer whale genetics: Redefining stock structure in a marine top predator." ScienceDaily. www.sciencedaily.com/releases/2013/07/130711135310.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins