Scientists are baffled as to what may be causing a high volume of whale deaths in the Gulf of Alaska this summer.
From May 2015 to mid-August, 30 large whales have stranded in the region, triggering an investigation into the cause of the "unusual mortality event," the National Oceanic and Atmospheric Administration's National Marine Fisheries Service said in a statement.
"To date, this brings the large whale strandings for this region to almost three times the historical average," NOAA said.
The 11 fin whales, 14 humpback whales, one gray whale and four unidentified cetaceans have stranded along the shores of the Gulf of Alaska where water temperatures have consistently been above average for the four-month period.
In all of 2014, just five large whale strandings were reported in the western Gulf of Alaska.
Out of the 30 spotted whales, only one has been sampled as of Aug. 14. Most carcasses were floating and irretrievable, NOAA said.
While different species of whales prefer various climates, the fin whale and humpback whale can be found in most of the world's oceans. Humpback whales migrate to temperate and even polar waters during the summer before migrating back to tropical waters in the winter, according to the American Cetacean Society (ACS).
While fin whales are believed follow a similar pattern, taking to colder areas in the summer for feeding, the ACS said recent evidence suggests they may disperse across deep ocean waters.
In May when the strandings began, water temperatures in the region hovered a couple of degrees above normal in the mid-40s F, AccuWeather Senior Meteorologist Tom Kines said.
"Current water temperatures are also couple of degrees above normal," he said.
Coinciding with well above-normal sea surface temperatures, a record-setting algae bloom has been plaguing the Pacific from Alaska to California. The algae can produce a potent toxin that can be harmful to people, fish and marine mammals, NOAA said.