A rare right whale dolphin was found beached on the Oregon coast last week.

Experts say that this is only the fourth sighting of the dolphin species in more than two decades along Oregon’s northern coast.

The Oregonian/OregonLive reports that Nehalem Bay State park staff found the dead female whale dolphin along Manzanita Beach last Friday. Park staff then reported the incident to the Marine Mammal Stranding Network, which works to save stranded sea mammals and investigates what might have caused them to beach.

The Seaside Aquarium transported the 5-foot-long dolphin to Portland State University, where it will undergo a necropsy to determine the cause of death.

The cetacean species have the physical features of a bottlenose dolphin, albeit with the black and white coloring of an orca.

The Seaside Aquarium announced the sighting on its Facebook page.

The aquarium said that the right whale dolphin is often found in groups of 200 to 300, along with other cetacean species.

The organization added that the biggest threats to the right whale dolphin are drift nets deployed in open oceans, which are responsible for a 24 to 73 percent decline in the right whale dolphin population. According to the aquarium’s Facebook post, Oregon and California currently have laws that require fishermen to use sound warnings to keep marine mammals out of nets.

“Though sad, this has given us a unique opportunity to learn a little more about this incredible species. A huge thanks to the Nehalem Bay State Park for reporting the animal so quickly,” the aquarium said in its post.

