Study declares humpback comeback

The whale species' numbers have increased tenfold since protections were enacted some decades ago, researchers declare in a new study

STORY SUMMARY »

Endangered humpback whales have made a comeback in the North Pacific Ocean.

Their numbers have increased since international and federal protections were put in place in the 1960s and '70s -- to about 18,000 or 20,000 in 2004-06 from 1,500 in 1966, according to a study by about 400 whale watchers for Structure of Populations, Levels of Abundance and Status of Humpbacks. Humpback whales were classified as endangered in 1973 with the passage of the federal Endangered Species Act.

At least half of the North Pacific's humpback whales migrate between Alaska and Hawaii, and that population is the healthiest, according to the scientists.

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Humpback whales have increased overall in the North Pacific -- to about 18,000 or 20,000 in 2004-06 from fewer than 1,500 in 1966 -- but some populations are not doing well, the world's largest study of whales has found.

SPLASH at a glance » SPLASH: Structure of Populations, Levels of Abundance and Status of Humpbacks is an international effort to better understand the humpback whale population across the North Pacific. The effort also tries to assess the potential human impacts to the population. » Methods: More than 400 researchers from 10 countries contributed to a two-year study in feeding and wintering areas of humpbacks within the North Pacific. Field techniques such as photo identification and biopsy tissue sampling were used. » Where: The regions studied by SPLASH included western North Pacific wintering areas, the Hawaiian Islands, Mexico, Central America, California, Oregon, Washington, British Columbia, the western Gulf of Alaska, southeastern Alaska including the East Gulf Aleutian Islands and Bering Sea, and western North Pacific waters off Russia. » Findings: The humpback whale population in the North Pacific grew to about 18,000 or 20,000 in 2004-06 from fewer than 1,500 in 1966.

The humpback whale numbers began rising after international hunting of the species was banned in 1966 and the Marine Mammal Protection Act and Endangered Species Act were passed in the 1970s.

"To me it wasn't so much a surprise that the estimate for the entire population seems pretty healthy," said David Mattila, science and research coordinator for the National Oceanic and Atmospheric Administration's Hawaiian Islands Humpback Whale National Marine Sanctuary.

More than 400 researchers in 50 groups and 10 countries participated in the international effort called SPLASH (Structure of Populations, Levels of Abundance and Status of Humpbacks).

At least half of the humpback whales migrate between Alaska and Hawaii, and that population is the healthiest, Mattila said in an interview. But some isolated populations "are not doing that well," he said, such as the West Pacific population that breeds off Japan and the Philippines and migrates to Russia.

Some populations might have been so depleted when whaling ceased that it is taking them longer to recover, Mattila suggested. "Whales are long-lived and give birth one at time ... so if the population gets pushed too low, it may take quite a while to come back. Maybe that's what's happening in the west.

"I hope there is no illegal whaling, but other activities impact or kill whales," he added, noting significant scarring on whales from entanglement with fishing gear and debris.

Mattila said a steering committee met in Hawaii in 2003 to talk about an international study of humpback whale populations and migration patterns, and that SPLASH was launched in 2004.

"It was a massive effort," he said, reporting that researchers went to a few places no one had been since whaling days.

Data was collected from Hawaii, Mexico, Asia and Central America to Russia through the Bering Sea, the Aleutians, Canada and the Northwest Coast, reflecting the whales' travels of up to 4,000 miles from feeding areas to breeding grounds.

Retired Navy Vice Adm. Conrad C. Lautenbacher Jr., NOAA administrator, presented early results of the study at a recent Conference on the Biology of Marine Mammals in Cape Town, South Africa.

"Using NOAA ships and small boats, as well as a variety of vessels as diverse as Canadian coast guard ships and Philippine outrigger canoes, SPLASH researchers collected data about North Pacific humpback whales in all known feeding and breeding habitats between winter 2004 and winter 2006," he said.

Cascadia Research in Olympia, Wash., central coordinator of SPLASH, analyzed 18,469 photographs of whale flukes, taken during 27,000 approaches of humpback whales. Identified were 7,971 individual whales.

Patterns of whale movements and estimated population sizes were calculated from the matched photographs, but scientists do not know how many populations there were, Mattila said.

"We recognize three separate ones," he said, explaining some populations overlap and others are isolated.

Genetic studies under way on 6,178 tissue samples should tell scientists more about the population structure, Mattila said.

He said the Hawaiian Islands Humpback Whale National Marine Sanctuary coordinated all work in Hawaii with about eight different teams, plus others studying whales in Hawaii at that time.

Humpback whales have a complex system of movement throughout the North Pacific, but some patterns emerged, John Calambokidis of Cascadia Research said at the meeting in South Africa.

He said the Alaska and Hawaii populations are strongly connected, a small population of Russian whales seems to breed almost exclusively off Asia, and humpbacks that breed close to the equator in Central America seem to be a distinct group.

SPLASH's data suggests there is a "missing" breeding ground, used mostly by whales from the Bering Sea and the Aleutians, Calambokidis said. The location is not known, but it most likely is between Asia and Hawaii, he said.