A virus may be behind the unusually high number of dolphin deaths in the Mid-Atlantic, including along the Jersey Shore, this summer.
NOAA's website now calls cetacean morbillivirus the "tentative cause" of the mass deaths, "based upon preliminary diagnostic testing and discussion with disease experts."
NOAA says all 27 dolphins tested so far have been suspected or confirmed positive for the virus.
Authorities say the investigation is ongoing and officials are trying to identify any other contributing factors, such as other pathogens or biotoxins.
Cetacean morbillivirus most often affects the lungs and brain of ill animals, according to NOAA. Animals may appear thin or have respiratory problems due to pneumonia.
It is transmitted from animal to animal through inhalation of respiratory particles or direct contact. It cannot spread to humans.
Through Sunday, 488 dolphins have been found stranded between New York and North Carolina, with 71 in New Jersey, according to the Asbury Park Press.
The mysterious deaths were declared an "unusual mortality event" earlier this month, prompting federal officials -- led by the National Oceanic and Atmospheric Administration's fisheries service -- to investigate.
Morbillivirus has been linked to past large mortality events.