September 8, 2015

Unraveling the mystery surrounding Alaska’s dead whales

The state of Alaska is huge. With a coastline covering more than 31,000 miles, it can be overwhelming to the trained volunteers, National Marine Fisheries Service (NMFS) agency staff and marine scientists who police it looking for stranded marine mammals. These whales, dolphins, walruses and other animals can strand or wash up on very remote shores. Sometimes they survive, but sadly sometimes they do not. And pinpointing the cause is a challenge.

Humpback whales, © NOAAUnlike with land-based wildlife, we cannot simply travel to a forest, grassland or other habitat to see if there are any factors that could be harming the animals. To research whales and other marine mammals, we must rely largely on what scientists can learn from dead animals to tell us what happening to them as a species, and to their ocean environment. Every beached whale, while heartbreaking, can at least provide us some useful information that may help find a cause and allow us to take action to protect other whales from a similar fate. As a member of the Alaska Marine Mammal Stranding Network, I personally know how important the data from stranded marine mammals are to better understanding what’s impacting these amazing animals.

This May, a number of dead endangered fin whales were reported floating near Kodiak, Alaska. National Oceanic and Atmospheric Administration (NOAA) officials launched an investigation into these whale deaths. They examined a number of possible causes, including the Northern Edge military ocean-based exercise conducted in and around the Gulf of Alaska. Yet officials found no evidence connecting the exercise to the deaths of the fin whales. In fact, they were unable to pinpoint any one cause.

Humpback Whale Feeding Frenzy, ©Alice Cahill

As the investigation went on, more dead whales washed ashore. By August 20th there were 30 reported dead whales: 11 fin whales, 14 humpbacks, one gray whale and four unidentified cetaceans. At this point, it was clear that the problem was larger than the incident in May. NOAA has officially declared what’s known as an UME – an Unusual Mortality Event. That’s the term for a situation like this – where large numbers of dead marine mammals are washing ashore, and scientists can’t easily identify why. There have been 61 formally declared UMEs since the program began in 1991, giving experts resources to investigate these incidents and discover not only what factors are responsible, but what insight they can give us into the state of our oceans. Because when large numbers of animals start washing ashore, it’s a safe bet that there’s something larger happening that we just can’t see yet.

There have been only two other UMEs in Alaska – one in 2011 involving pinnipeds (seals), and one in 2006 involving sea otters. But this is the first involving large whales. Could these unexplained whale deaths in our region be linked to changes in the ocean? Some suspects include a developing El Nino, or the high Pacific Ocean surface temperatures being blamed on a persistent warm water mass nicknamed “The Blob”. Warm ocean water conditions can fuel large, persistent, and harmful algal blooms in Alaska and California waters – and experts believe the current warmer conditions could continue. So far, all the identified whales have been filter feeders. Could they be ingesting toxic algae? NOAA’s records show that UMEs traced back to biotoxins from harmful algal blooms have become more frequent since the mid-90s. Combined with the current warm water conditions, it’s certainly a possibility. As experts continue to investigate this UME, hopefully we’ll learn more about what’s responsible.

So what can you do to help? The most important thing is that if you live in or visit Alaska and see a dead or stranded marine mammal, please contact the Marine Mammal Stranding Network hotline immediately (877-925-7773). Only specially trained responders should approach marine mammals in distress. Getting the word to the right people as quickly as possible can save an animal’s life, or provide vital information to the scientists working to discover the cause of this UME.

As the investigation continues, it’s vital that we also work to face the changes that we know for certain are already happening in our oceans, impacting species from fish to birds to marine mammals. The world’s oceans are a sink for carbon from fossil-based fuels – leading to ocean acidification, which impacts small ocean prey with shells. Acidification and warming waters (which increase biotoxin incidents) are a double whammy for ocean animals like these whales. You can help by reducing your carbon footprint and by electing officials at all levels of government who address climate change now instead of kicking the can down the road for future leaders to grapple with.

Wildlife & Wild Places

Follow Defenders of Wildlife