The mystery of Alaska’s dead fin whales
Nine of these giant endangered animals have died recently; all at roughly the same time and place. What’s going on?
With total population numbers only in the tens of thousands, a die-off of the world’s second largest mammal is significant. Since May, at least nine fin whales have been discovered floating dead in the waters between Kodiak and Unimak Pass in Alaska, and no one is quite sure why.
“It is an unusual and mysterious event that appears to have happened around Memorial Day weekend,” said Kate Wynne, a marine mammal specialist from the University of Alaska Fairbanks. “We rarely see more than one fin whale carcass every couple of years.”
At the end of May the National Oceanic and Atmospheric Administration (NOAA) contacted Wynne telling her that crew aboard an Alaska Marine Highway System's ferry had encountered and photographed a number of dead whales. Over the next two weeks, reports continued to come in from boaters, fishermen and pilots relaying more sightings of whale carcasses. Based on various photos and reports, Wynne and the NOAA concluded that at least nine fin whales had succumbed in a relatively small area.
Grimly, the whale bodies are now drifting around Kodiak Island.
“It is really perplexing for a number of reasons,” said Wynne. “They appear to have all died around the same time. And the strange thing is they are all one species, with the exception of one dead humpback whale found in a different location.”
“So part of the mystery is why just fin whales? Why not their prey? Why are there not other consumers in the system showing up in mass die-off mode?” she said.
© Fin whales forage in Uganik Bay on the west side of Kodiak Island. (Photo: UAF Gulf Apex Predator-Prey Project)Fin whales, which reach lengths of 65 to 80 feet and weigh almost 80 tons, are baleen feeders and strain their food from the water through baleen plates. They feed in close groups, leading Wynne to think that perhaps a formation of them consumed something toxic.
So far, two carcasses have come ashore. Wynne and another marine mammal specialist took samples from one, which are presently undergoing lab analyses. Wynne has also been working with the NOAA doing community outreach to collect more information and asking people to report anything unusual like dead birds or fish.
“In the meantime we are mapping and tracking reported whale carcasses, collecting water samples to look for harmful algal blooms and recording changes in sea water temperature,” she said. “So far there is no 'smoking gun' in this environmental mystery.”