Hawaii residents are familiar with humpback whales and dolphins, but scientists have found a population of in-between-size marine mammals that caters to the Kona Coast.

Using satellite-tracked tags for the first time, biologists have tracked the movements of Blainville's beaked whales, odd-looking cetaceans that grow to about 15 feet long and can spend at least an hour submerged, reaching depths greater than 3,000 feet.

In years past, aerial observations and photo identification were conducted, but both methods failed to provide sufficient movement patterns.

So researchers spent up to two months in 2006 and 2008 tagging the dorsal fins of eight whales in six different groups. They found that the whales stuck close to the Big Island, often for months at a time.

“;It's clear that there's a strong affiliation with the island of Hawaii,”; said Greg Schorr, a research biologist of Cascadia Research Collective who was part of the research team. Results of the study, funded by the Navy and National Marine Fisheries Service, were published online in the journal Endangered Species Research.

Island topography and the availability of prey, primarily fish and squid, are believed to be factors prompting the whales to remain along the Kona Coast rather than venturing to the Hilo side.

Tracking patterns also allowed researchers to gain insight into a close-knit social structure, with the whales often traveling in groups.

It was also determined the whales traveled in the Alenuihaha Channel, between Maui and the Big Island, where naval sonar exercises have been conducted in the past. According to the study, there has been no documented mass stranding of Blainville's beaked whales in connection with naval exercises in Hawaii waters.

Nevertheless, researchers in the study said the potential impact of sonar is high due to the overlap of naval training areas, whale movement patterns and the sensitivity to sonar in beaked whales observed elsewhere.

Schorr said they might deploy some satellite tags before a planned sonar exercise to study its effect on the small population.