The strange behavior of its pod had marine mammal experts so concerned over the weekend that they were preparing for a mass stranding of up to 200 animals.

"We had experts from as far away as the East Coast on standby to fly out," said marine veterinarian Robert Braun, a consultant to the National Marine Fisheries Service.

Ultimately, the pod was coaxed back into deep water. Braun said it's possible that studies on the calf will show nothing amiss—that the newborn may simply have been separated from its mother for too long.

Hanalei residents woke Saturday to a sight that National Oceanic and Atmospheric Administration scientists say has never before been recorded in Kaua'i waters. A tightly packed pod of 100 to 200 melon-headed whales, dolphins that grow to 9 feet in length and up to 500 pounds in weight, was sitting just off the shore.

"There was a big mass of these small black whales. It was awesome," said schoolteacher Diane Daniells.

The Navy halted the use of active sonar during its RIMPAC exercises off Kaua'i on being informed of the whale behavior, but RIMPAC spokesman Navy Lt. Erik Reynolds said the whales appeared to have entered the bay before vessels started the use of their sonar Saturday morning.

Reynolds said four Japanese ships and two U.S. Navy ships were tracking an underwater target—a torpedo that sounds on sonar like a submarine—on the Pacific Missile Range Facility underwater test range. The ships were in transit Friday and had not been using sonar on the range. Reynolds said NOAA reports indicated the whales were seen in Hanalei Bay at 7:30 a.m. Saturday. The first use of active sonar was at 8:33 a.m. Saturday, he said.

He said the Navy and RIMPAC would "continue to restrict active sonar operations until we have an opportunity to study this unusual situation."

The nearest military ship was 19 miles from Hanalei during the exercises, he said.

Braun arrived at Hanalei about 7:30 p.m. Saturday. He said he could see no individual whales that appeared injured, but felt that the pod as a whole was exhibiting signs of being stressed.

"There are things you look for in cases of acoustical trauma (damage from loud noise). We did not see any individuals that behaved" as if they had suffered the kind of damage associated with loud noises, he said. Those behaviors include floating high in the water, erratic behavior and abnormal swimming.

However, this pod of deep-water whales was in unusually shallow water and females' nursing behavior was disrupted. Braun and others feared a mass stranding like those that have occurred in other parts of the world could present them with the whole pod on the beach.

He decided that for the protection of the entire pod, it was prudent to authorize a rescue attempt that would include only paddle-powered boats like canoes and kayaks. Members of the Hanalei Canoe Club made a 600-foot cable of morning glory vines collected from the shore, and used it Sunday morning to herd the animals away from shore. One canoe was at each end of the vine cable, and kayaks and canoes paddled along the back side of the curve of vines.

"The 'lau' of beach morning glory vines, I felt, would break up if an animal became entangled in it, while a rope or a net wouldn't," Braun said.

The whales initially approached the lau, then veered off to the west and then out to sea.

"It was a Hollywood script departure. (When the water depth reached) 150 to 200 feet, they began porpoising and some were jumping out of the water. They took off in a manner that I've seen them take off in deep water," he said.

But that Sunday evening, Daniells was with her son and friends at Lumaha'i Beach when a lone 3-foot calf swam up onto the sand. It had an injury on its face and its jaw was chattering.

"It was making a click-click-click sound with its teeth," she said.

Daniells wrapped herself around the animal, and wrestled it around to face the horizon.

"It made whale sounds, a high-pitched squeaking. It was so strong, so strong," she said.

Once it was facing the ocean, the calf swam away. A calf the same size washed ashore dead a mile away on Hanalei Bay's shore Monday. There was no way to confirm if it was the same animal.

State wildlife biologist Don Heacock told Braun that the dead calf had markings consistent with what are called fetal folds, "coloration patterns associated with a fetal dolphin as it is folded within the uterus." That suggested it was very young, Braun said.

The baby whale will be shipped to the marine mammal center at Fort Cronkhite in Sausalito, Calif., for a complete necropsy, said Wende Goo, Pacific Region spokesperson for NOAA Fisheries.

Wildlife officials will study satellite photos to see if they can identify possible toxic algae blooms offshore, will review military records of sonar use, will study the calf necropsy results and other clues to try to determine the cause of the whale pod's distress, she said.

To reach Jan TenBruggencate e-mail jant@honoluluadvertiser.com or call (808) 245-3074.