Marine mammal researchers were thrilled yesterday to spot more than 80 rare Fraser's dolphins off the Big Island's Kona Coast.

Sightings of the tropical species have been documented only twice before in Hawaiian waters, and those were more than 650 miles west of Kaua'i, said Robin Baird, a researcher with the Cascadia Research Collective.

"These dolphins are found throughout the tropics, in very deep water," said Baird of the dolphins, noted for their small dorsal fins and short beaks. "None of us on board had ever seen Fraser's dolphins before."

"It's exciting," said David Schofield, marine mammal rescue coordinator for the National Oceanic and Atmospheric Administration, who was not on the boat.

Photos of the dolphins are at www.cascadiaresearch.org.