Whale population size, dynamics determined based on ancient DNA

May 09, 2012

Estimates of whale population size based on genetics versus historical records diverge greatly, making it difficult to fully understand the ecological implications of the large-scale commercial whaling of the 19th and early 20th centuries, but a comparison of DNA samples from modern and prehistoric gray whales supports the idea that the population was substantially larger pre-whaling and saw a sharp, recent decrease that is consistent with whaling as the cause. The full results are reported May 9 in the open access journal PLoS ONE.

Previous estimates of pre-whaling population size in using historic records and census modeling suggest there used to be about 15,000 to 35,500 eastern Pacific gray whales. In contrast, estimates from genetic data suggest a much higher original population size of about 78,000 to 116,000 individuals. This discrepancy, though, could be explained by a pre-whaling decrease in population. The authors of the current study, led by Elizabeth Alter of City University of New York (York College), set out to test this hypothesis.

They isolated DNA from whale bones excavated from archaeological sites, ranging from about 150 to 2,500 years old. By comparing these sequences with sequences from modern whales, they determined that a severe decline in occurred recently, suggesting that the original population size was indeed larger than estimated based on historical record and arguing against population decline caused by any pre-whaling forces.

"Retrieving DNA from ancient whales allows more direct insights into their population histories than using modern DNA alone. In this case, we were able to look at pre-whaling specimens of gray whales, and found that the genetic data are consistent with a sharp and recent bottleneck -- very likely the result of . As methods for retrieval and analysis of ancient DNA improve, we'll be able to increasingly refine for heavily exploited species like whales."

Explore further: New bird species confirmed 15 years after first observation

More information: Alter SE, Newsome SD, Palumbi SR (2012) Pre-Whaling Genetic Diversity and Population Ecology in Eastern Pacific Gray Whales: Insights from Ancient DNA and Stable Isotopes. PLoS ONE 7(5): e35039. doi:10.1371/journal.pone.0035039

Related Stories

Norway fails to fulfill whaling quota

Aug 21, 2006

Norway says its fishermen will not be able to fulfill this year's whaling quota, with about 500 minke whales caught out of the quota's 1,052.

'Bycatch' whaling a growing threat to coastal whales

Jun 23, 2009

Scientists are warning that a new form of unregulated whaling has emerged along the coastlines of Japan and South Korea, where the commercial sale of whales killed as fisheries "bycatch" is threatening coastal stocks of minke ...

Levy not law will save the whales

Sep 06, 2010

(PhysOrg.com) -- Conservationists would save more whales from the harpoon if the whale-watching public and industry were willing to pay a levy that could be used to persuade those countries currently engaged in whaling to ...

Recommended for you

Scanning robot helps put insect collection online

7 hours ago

A robot capable of scanning a tray of insect specimens in a few minutes will help make the virtual images and tagging information available to the public online, according to South Dakota State University ...

New mushroom discovered on campus is the first since 1985

7 hours ago

Two researchers who recently named the first new species of mushroom from the UC Berkeley campus in more than 30 years are emphasizing the need for continued green and open space on campus, as well as a full-fledged ...

Rare new species of plant: Stachys caroliniana

Nov 21, 2014

The exclusive club of explorers who have discovered a rare new species of life isn't restricted to globetrotters traveling to remote locations like the Amazon rainforests, Madagascar or the woodlands of the ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.