More dead whales have been found in the Gulf of Alaska following the sightings of nine fin whale carcasses in late May and early June.

The Alaska Dispatch News reports that fishermen, pilots and survey crews have reported five additional dead whales over the past several weeks, including four humpbacks and one fin whale.

University of Alaska Fairbanks marine mammal specialist Kate Wynne says one theory is that the whales died from a toxin related to warmth-induced algae blooms in the Gulf of Alaska waters.

But she says scientists have tested a sample taken from the partially decomposed carcass of a dead fin whale and it did not contain the algae-produced toxin domoic acid. Other results are still pending.

Wynne says it's possible that more whale carcasses could be reported soon.