Endangered Humpback Whales Recovering in North Pacific

LA JOLLA, California, October 19, 2011 (ENS) – There are at least 1,000 more humpback whales in the North Pacific Ocean than previously estimated, say scientists at NOAA’s Southwest Fisheries Science Center in La Jolla.

In a paper published in the current issue of the journal “Marine Mammal Science,” the scientists say the increase follows a refined statistical analysis of data compiled in 2008 from the largest-ever survey to assess humpback whale populations throughout the North Pacific.

The number of North Pacific Humpback Whales in the 2008 study entitled, “Structure of Populations, Levels of Abundance and Status of Humpbacks,” or SPLASH, was estimated at just under 20,000, based on a preliminary look at the data.

The new research indicates the population to be higher than 21,000 animals.

For comparison, only 1,400 humpback whales were estimated to be in the North Pacific Ocean as commercial whaling ended in 1966.

“These improved numbers are encouraging, especially after we have reduced most of the biases inherent in any statistical model,” said co-author Jay Barlow, NOAA’s Fisheries Service marine mammal biologist at the Southwest Fisheries Science Center.

Humpback whale surfaces to breathe in the eastern tropical Pacific. (Photo by Jim Cotton courtesy NOAA)

“We feel the numbers may even be larger since there have been across-the-board increases in known population areas and unknown areas have probably seen the same increases,” Barlow said.

The SPLASH research was a three-year project begun in 2004 involving NOAA scientists and hundreds of other researchers from the United States, Japan, Russia, Mexico, Canada, the Philippines, Costa Rica, Panama, Nicaragua and Guatemala.

It was the first systematic survey ever attempted to determine the humpback whales’ overall population, structure, and genetic makeup in the North Pacific.

Researchers were able to quantify the number of humpback whales by photographing and cataloguing more than 18,000 pictures of the animals’ tails, or flukes. The pigmentation patterns on flukes are unique to each animal.

Scientists determined population numbers by comparing photographs taken in northern feeding grounds – around the Pacific Rim from California to Kamchatka, Alaska – with matches of the same animals in the tropical waters of southern breeding areas as far as 3,000 miles away.

“This latest revision to the study provides an accurate estimate for humpback whales in an entire ocean that could not have been possible without researchers working together to pool data,” said co-author John Calambokidis, senior research biologist and co-founder of Cascadia Research.

“While populations of some other whale species remain very low,” he said, “this shows that humpback whales are among those that have recovered strongly from whaling.”

Copyright Environment News Service (ENS) 2011. All rights reserved.