MANZANITA — A rare female northern right whale dolphin washed ashore on Manzanita Beach on the Oregon Coast on Saturday, June 9, the Seaside Aquarium reported.

The animals tend to live much farther south and in deeper offshore waters, although they can range as far north as Alaska, Tiffany Boothe of the aquarium said.

The whale dolphin moves south during colder water temperature periods and north during warmer water periods.

Boothe said that aquarium staff have only seen four of these unique dolphins since 1995, when the aquarium became involved with the Northern Oregon/Southern Washington Marine Mammal Stranding Network.

The northern right whale dolphin is known to travel in groups of up to 2,000, although they are more often found in social groups of 200 or 300.

The largest threat to these dolphins is from high-sea drift nets.

Drift nets are considered responsible for a 24 to 73 percent population decline. In Oregon and California, law requires fishing boats to use pinger devices that deliver acoustic warnings into the water column to reduce bycatch.

The dolphin beached in Manzanita was picked up by the Seaside Aquarium and transferred to Portland State University, where a necropsy was preformed, Boothe said. Preliminary results from the necropsy were inconclusive.