Federal officials plan to conduct necropsies on two dolphins found dead of no apparent causes within a week.
A melon-headed whale was discovered dead in waters near Flat Island off Kailua on Friday morning, and a dead short-finned pilot whale was found in waters near the shoreline on North Kauai on July 25.
Both are members of the dolphin family.
While the two deaths happened within days, the number of deaths for whales and dolphins in Hawaii remains within the normal range of about two a month, said David Schofield, the federal marine mammal response coordinator in Hawaii.
Schofield said there have been about 20 to 25 strandings involving dolphins or whales a year in Hawaii and that the stranding on Kauai was the second in July — the first taking place in Kaneohe Bay.
Schofield said there are numerous potential causes for the deaths, including disease and viral infections.
He said the necropsy will also look at whether Navy sonar was related to the stranding.
The carcass of the melon-headed whale was taken to Hawaii Pacific University for analysis.
U.S. Pacific Fleet spokesman Mark Matsunaga said the Navy is fully cooperating with the National Marine Fisheries Service on the investigation.
"It would be premature and irresponsible to speculate (about) the cause," Matsunaga said.
"The Navy cares about the environment."
On Thursday the melon-headed whale was seen swimming in circles between Flat Island and Lanikai Beach, indicating it was in distress. The public was warned to stay away from nearby waters.
The melon-headed whale, 9 feet long and weighing 400 to 500 pounds, was found dead at about 11 a.m. Friday.
Federal fisheries officials said while the short-finned pilot whale found near the shoreline on North Kauai had circular wounds determined to be caused by sharks, they’re still gathering information to determine the cause of its death.
The injuries, common among marine mammals including whales, were superficial and not related to the cause of the stranding, Schofield said.
The short-finned whale, or Globicephala macrorhynchus, about 16 feet long and weighing about 3,000 pounds, was found at Hanalei Bay on July 25.
A team consisting of federal fisheries workers conducted the necropsy on the short-finned pilot whale through the early morning of July 26, but the results did not indicate the cause of death.
National Oceanic and Atmospheric Administration spokeswoman Wende Goo said a tissue analysis will take from several weeks to months.
At the request of NOAA, a Navy aerial survey was conducted on the day of the stranding within a 15-nautical-mile radius, and no other strandings were detected, authorities said.
Goo said a Hawaiian cultural blessing was conducted at the stranding site in Hanalei. She said the carcass was buried on Kauai near the stranding site after the necropsy was completed.
Some sonar training occurred south and west of Kauai in the 72 hours preceding the stranding, but none was reportedalong Kauai’s north shore, the Navy said.
Matsunaga said the Navy uses midfrequency active sonar to detect extremely quiet submarines that pose a threat to national security.
In July 2004 about 150 to 200 melon-headed whales swam into shallow water of Hanalei Bay shortly after naval maneuvers and stayed for 27 hours.
A researcher involved in looking at the reason for the incident said no conclusion was reached that active sonar was the cause.
At about the same time, a similar aggregation of melon-headed whales occurred in a bay in Rota in the Northern Marianas, the researchers said.
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Star-Advertiser reporter Rosemarie Bernardo contributed to this report.
