American scientists have reported a sharp increase in the number of dead whales found in the Gulf of Alaska. From May through August, 30 whales washed up along the coast of Alaska.

　　Scientists say there may be a connection between the animals' deaths and warming waters. They say the Arctic is getting warmer faster than any place on the planet.

　　Deborah Fauquier is a marine mammal scientist at NOAA – the National Oceanic and Atmospheric Administration. She wants to learn why so many whales have died this year.

　　"And the average for the whole year generally is eight. So it is definitely a significantly elevated (level) and for us that was a reason of concern."

　　She says scientists have formed some ideas about what caused the deaths.

　　"We might be able to, you know, figure out ‘is it a virus?' ‘Is it,' you know, ‘a ship strike?' ‘Is it a harmful algal bloom?'"

　　Algae are simply plants or plant-like organisms. Most algae are safe. But scientists say the less-common toxic alga can cause brain damage or even death. In June, the largest alga bloom in more than 10 years was seen along the Pacific coast, from California to Alaska. Scientists say it grew big because of warm water and sunny, calm weather. The alga bloom forced officials to close fishing areas in several states.

　　Deborah Fauquier says scientists will look for evidence of the harmful alga in the whales.

　　"So some of the whales actually filter the phytoplankton and the zooplankton, which are the little insects that eat the grass in the sea, basically. So, they get the toxins through that method. The other one is that they eat the fish that eat those. So it just depends where on the food web they eat and as you go higher up the food web, more toxin gets concentrated."

　　The waters around Alaska began warming in 2014. The water temperature continues rising. It is now three degrees Celsius warmer than normal.

　　Scientists blame the weather event known as "El Nino" and wind patterns for the warming. The scientists say the warming is not linked to climate change. But industrial gas emissions are warming the planet. They are causing the Arctic to warm faster than anywhere else.

　　At the beginning of the melt season, Arctic sea ice was at its lowest level ever recorded. Mrs. Fauquier says that is a problem for marine mammals. Polar bears and walruses, for example, live and breed on the ice and use it as a place from which to hunt.

　　"For Arctic species -- species that normally like cold water -- it is going to change the phytoplankton, so it's going to change the base of the food web. It is going to change the fish. They may go farther north because they don't like warm water. And so then the predators that are mobile are going to have to follow those fish or if they can't follow them, then they can starve."

　　Mrs. Fauquier says NOAA hopes to learn why so many whales died. She said knowing the cause is the first step to understanding how to solve the problem.

　　I'm Bob Doughty.

　　VOA's Rosanne Skirble reported on this story. Christopher Jones-Cruise adapted it for Learning English. George Grow was the editor.