The National Oceanic and Atmospheric Administration's Fisheries Service says a dead newborn orca calf found on Washington's Olympic Peninsula last week belongs to a population of endangered killer whales.

The agency said Tuesday that scientists are trying to determine what killed the 7 1/2-foot-long male calf. He was found on a Dungeness Spit beach.

An initial DNA analysis showed the calf was a member of the southern resident killer whales that spend summer months in Puget Sound.

NOAA spokesman Brian Gorman says the death is not unusual and that mortality rates among killer whales tends to be high.