Fidelity to breeding grounds shapes whales

The research by Wildlife Conservation Society, the American Museum of Natural History and other organisations will help scientists better understand how humpback whale populations evolve over time.
The research by Wildlife Conservation Society, the American Museum of Natural History and other organisations will help scientists better understand how humpback whale populations evolve over time. ST PHOTO: CHANG AI-LIEN

Findings from DNA study of 3,000 humpbacks to help in protecting them

Scientists conducting the largest study of its kind of the DNA of more than 3,000 humpback whales have found that whales returning faithfully to calving grounds year after year play a major role in how populations form.

The work was done by Wildlife Conservation Society (WCS), the American Museum of Natural History, and other organisations.

The research will help scientists better understand how humpback whale populations evolve over time and how to best advise international management authorities, said WCS in a statement.

The researchers used mitochondrial DNA from skin samples of the whales across the Southern hemisphere and the Arabian Sea to examine how populations are related.

The data from mitochondrial DNA - which traces maternal lineages - revealed that population structure is driven largely by female whales that return annually to the same breeding grounds, and the early experience of calves accompanying their mothers on their first round-trip migration to the feeding grounds, said the society.

Returning to these migratory destinations over generations is known as "maternally directed site fidelity".

"Exploring the relationships of humpback whales around the Southern hemisphere has been a massive undertaking requiring years of work and collaboration by experts from more than a dozen countries," said Dr Howard Rosenbaum, director of WCS's Ocean Giants Programme and lead author of the study.

"Our findings give us insights into how fidelity to breeding and feeding destinations persist over many generations... From these efforts, we are in better positions to inform actions and policies that will help protect Southern hemisphere humpback whales across their range, as well as in the Arabian Sea."

Humpbacks can grow up to about 15m in length and belong to the rorqual family of whales, whose shape and colour patterns on the dorsal fin and tail are specific to each animal, as fingerprints are to humans.

A version of this article appeared in the print edition of The Straits Times on July 14, 2017, with the headline 'Fidelity to breeding grounds shapes whales'. Print Edition | Subscribe