As per reports, marine biologists in the United States have launched an investigation to discover the cause that led to death of about 30 large whales in the western Gulf of Alaska. A federal agency declared this as an unusual mortality event.

National Oceanic and Atmospheric Administration (NOAA) spokeswoman Julie Speegle said on Friday that they are not clear what has led to the mass death of the marine creatures. But she suspected that the incident could be linked to a toxic algae bloom in the Pacific Ocean, Reuters reported.

Ms. Speegle said, "Biotoxins will be one of the top priorities but not the only priority that we'll be looking at to rule in or rule out whether it's playing a role in this death investigation and these mortalities, both in Canada and the US".

As per NOAA reports, the bloom initially appeared in May, the same month in which first dead whale was spotted. Speegel said that any infectious diseases could also be the possible culprits in the death of whales, as are other environmental factors.

According to the NOAA, officials said at a teleconference on Thursday that the whale deaths may be tied to a larger marine pattern. The formal investigation into this case is expected to begin in September, and could take months, even years, of data collection and analysis, Speegle said.

According to Bree Witteveen, a Kodiak-based marine mammal specialist with the Alaska Sea Grant program, one difficulty during the investigation will be to reach the dead whales in order to collect samples, as Alaska's coastline is vast, largely uninhabited and jagged in many places.