About 230 dolphins have died and washed ashore on the East Coast this summer. Typically, 65 dead dolphins are reported washed on shores a year.
The Virginia Aquarium Stranding Response Team has performed necropsies on dead dolphins to determine the cause.
Stranding resuce organizations say they're still unsure what has caused the rise in dolphin deaths. Bob Schoelkopf of the Marine Mammal Stranding Center in New Jersey noted some of the dolphins have respiratory infections.
Dead dolphin bodies have appeared on the coastlines of New York, New Jersey, Delaware, Maryland and Virginia this summer.