Nearly 120 corpses have washed ashore in coastal states from New York to Virginia in July and the first week of August, which is much higher than the normal number of strandings attributed to natural deaths. Virginia has had the highest mortality, with 64 animals found during that period.

One of the dolphins tested positive for morbillivirus, a measles-like, airborne virus that's often fatal in dolphins.

A morbillivirus epidemic hit East Coast bottlenose dolphins in 1987 and 1988, wiping out at least 900 animals and striking a major blow to that population of migratory dolphins.

"Because of the sheer number of animals [dying] over multiple states, people are very concerned that this might be a repeat," said Trevor Spradlin, a marine mammal