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Blue Whale Herd Stages a Big Buffet in the Bay : Mammals Thrill Students, Tourists

November 23, 1986|MARK A. STEIN | Times Staff Writer

MOSS LANDING, Calif. — Scientists say an "extended herd" of perhaps 30 blue whales--the largest animal on earth--is picnicking in Monterey Bay, giving researchers an unusual opportunity to study the massive and mysterious marine mammals.

The whales' six-week-long feast also is said to be giving a great show to amateur whale-watchers, who brave stomach-wrenching eight-foot seas in charter boats to get a look at the 80-foot-long creatures.

On most days, the whales cooperate, making what some researchers said were repeated wave-top feeding "lunges" in an effort to scoop up their individual daily ration of eight tons of krill, a small, pink, shrimp-like crustacean.

On Friday and Saturday, however, reporters and other whale-watchers did not see any whales, either from the air or from boats. Tour guides blamed rough seas.

A Chance for Study

Still, students and other scientists at the Moss Landing Marine Laboratory, a research facility affiliated with the state university and colleges system, report frequent encounters. They said these meetings already have allowed them to observe several unknown or little-seen aspects of the whales' feeding habits and social organization.

"I have already learned a lot," said Bernd Wursig, a professor of behavioral biology. "We're seeing such things as 'lunge feeding' in tandem and sometimes in trio. They are actually cooperating with one another."

Photo identification and underwater microphones indicate the grouping is neither random nor casual, he said.

"They can be thought of as an extended herd," Wursig said. "We know they communicate with each other." In particular, he said, whales seem to sense when other members of the group find a school of krill.

Scientists said it is not uncommon for some blue whales to pass through Monterey Bay while migrating between feeding grounds off Alaska and breeding grounds at some unknown place in the tropics.

Long Stay This Year

But never before have so many of the behemoths, which are larger than the largest dinosaur, stayed so long in the area. They have been lolling in the waters between Monterey and Santa Cruz since early in October, and show no signs of leaving.

One reason for that--perhaps the only reason, scientists believe--is an abundance of krill. Unusual upwellings of nutrient-rich water from an offshore canyon provide a rich supply of the tiny phytoplankton on which the prolific, inch-long crustacean feeds.

Jill Schoenherr, a graduate student of marine mammal feeding ecology, said she has seen "incredible swarms" of krill in the bay. "They're literally jumping out of the water," she said.

They also form what Wursig said are "dense clouds" as much as 540 feet below the surface--and the blue whales are diving in teams to harvest them. As one whale swallows part of the school, another acts as a "wall" to prevent the prey from darting out of the way.

Scientists said they have observed the activity with side-scanning sonar and other deep-sea research equipment.

"It (cooperative behavior) has been guessed at before," Wursig said, "but we can now describe it in much more detail, having seen it so closely."

Dedicated whale pairs also have been observed swimming together, Schoenherr said, but it is not known if this is a characteristic of full-grown blues or immature adults.

Breathing a Spectacle

For the non-scientist, however, the most spectacular part of the whales' show is when they break the ocean surface to "blow," or breathe.

"What is most amazing," Schoenherr said, "is that you will see them blow, then you see their back--and see their back and see their back and see their back. You don't think it is ever going to end. Then you see a tiny dorsal fin, the flukes and it's gone.

"You cannot believe how big they are."

Plenty big is how big. Full-grown blue whales have stretched to 98 feet, and are estimated to weigh as much as 196 tons.

In calm seas, scientists said big blues dart to within 20 or 30 feet of the flotilla of whale-watching craft that regularly ply the bay.

Tourist Business Booms

Although the massive creatures come to within three to five miles of land, they usually cannot be seen from shore. Charter boats and rental aircraft do a brisk business with tourists.

Twenty-five years ago, the whale had been hunted nearly into extinction. An international agreement outlawed blue-whale hunting in 1965, and the species has recovered.

The Sierra Club estimates there are 1,200 to 1,700 in the North Pacific, a few hundred in the North Atlantic and 9,000 in the Southern Hemisphere.

However, relatively little is known of blue whales, which usually keep to the open sea. Scientists are still unsure, for example, where they breed. Migration patterns also are not fully understood, Schoenherr said.

Blue whales breathe through paired blowholes atop their heads, and in color are light bluish-gray mottled with gray or white. In warm waters, tiny yellowish creatures called diatoms cling to their bellies, causing early seafarers to name it the sulfur-bottom whale.

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