Featured Research

from universities, journals, and other organizations

Genetic analysis disputes increase in Antarctic minke whales

Date:
January 18, 2010
Source:
Oregon State University
Summary:
A new genetic analysis of Antarctic minke whales concludes that population of these smaller baleen whales have not increased as a result of the intensive hunting of other larger whales -- countering arguments by advocates of commercial whaling who want to "cull" minke whales.

Minke whale in Ross Sea, Antarctica.
Credit: Mila Zinkova / Courtesy of Wikipedia

A new genetic analysis of Antarctic minke whales concludes that population of these smaller baleen whales have not increased as a result of the intensive hunting of other larger whales -- countering arguments by advocates of commercial whaling who want to "cull" minke whales.

Antarctic minke whales are among the few species of baleen whales not decimated by commercial whaling during the 20th century, and some scientists have hypothesized that their large numbers are hampering the recovery of deleted species, such as blue, fin and humpback, which may compete for krill.

This "Krill Surplus Hypothesis" postulates that the killing of some two million whales in the Southern Ocean during the early- and mid-20th century resulted in an enormous surplus of krill, benefiting the remaining predators, including Antarctic minke whales.

But the new analysis, published in the journal Molecular Ecology, estimates that contemporary populations of minke whales are not "unusually abundant" in comparison with their historic numbers. Using a novel genomic approach, the scientists were able to calculate the long-term population size of Antarctic minkes as roughly 670,000 individuals -- which is similar to estimates of current population size from sighting surveys.

"Some scientists involved in the International Whaling Commission have suggested that Antarctic minke whales have increased three-fold to eight-fold over the last century because of the lack of competition for krill," said Scott Baker, a whale geneticist at Oregon State University and associate director of the Marine Mammal Institute at OSU. "But until now, there has been little evidence to help judge what historic populations of minke whales actually were.

"Our study clearly shows that minke whales today have a great deal of genetic diversity, which reflects a long history of large and relatively stable population size," he added.

Along with Kristen Ruegg and Steve Palumbi of Stanford University, Baker and OSU postdoctoral fellow Jennifer Jackson analyzed genomic DNA from 52 samples of minke whale meat purchased in Japanese markets. The whales had been killed during Japan's controversial "scientific whaling" program in the Antarctic. By amplifying and sequencing a large number of genes, the scientists were able to estimate the historic range of population sizes necessary to produce and maintain the levels of genetic diversity found in the individual minke whales they tested.

"This genomic approach is a significant advance over most previous studies, which have examined diversity using only a handful of genetic markers," Baker said.

Funding for the research was provided by a grant from the Lenfest Ocean Program and the Marsden Fund of the New Zealand Royal Society.

The Southern Ocean is one of the world's largest and most productive ecosystems and in the 20th century went through what Baker called "one of the most dramatic 'experiments' in ecosystem modification ever conducted." The elimination of nearly all of the largest whales -- such as the blue, fin and humpback -- removed a huge portion of the biomass of predators in the ecosystem and changed the dynamics of predator-prey relationships.

Blue whales were reduced to about 1-2 percent of their previous numbers; fin whales to about 2-3 percent; and humpbacks to less than 5 percent. "The overall loss of large whales was staggering," Baker said.

"It is possible that the removal of the larger whales would have meant more food for minkes," Baker said, "but we don't know much about the historic abundance of krill and whether the different whale species competed for it in the same places, or at the same time. It is possible that there might have been enough krill for all species prior to whaling."

The scientists also say that current minke whale populations may be limited by other factors, including changes in sea ice cover.

"The bottom line is that the Krill Surplus Hypothesis does not appear to be valid in relation to minke whales and increasing hunting based solely on the assumption that minke whales are out-competing other large whale species would be a dubious strategy," Baker said.


Story Source:

The above story is based on materials provided by Oregon State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Kristen C. Ruegg, Eric C. Anderson, C. Scott Baker, Murdoch Vant, Jennifer A. Jackson, Stephen R. Palumbi. Are Antarctic minke whales unusually abundant because of 20th century whaling? Molecular Ecology, 2010; 19 (2): 281 DOI: 10.1111/j.1365-294X.2009.04447.x

Cite This Page:

Oregon State University. "Genetic analysis disputes increase in Antarctic minke whales." ScienceDaily. ScienceDaily, 18 January 2010. <www.sciencedaily.com/releases/2010/01/100114104935.htm>.
Oregon State University. (2010, January 18). Genetic analysis disputes increase in Antarctic minke whales. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2010/01/100114104935.htm
Oregon State University. "Genetic analysis disputes increase in Antarctic minke whales." ScienceDaily. www.sciencedaily.com/releases/2010/01/100114104935.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Newsy (July 30, 2014) The Peace Corps is one of several U.S.-based organizations to pull workers out of West Africa because of the Ebola outbreak. Video provided by Newsy
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
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:
from the past week

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