The Arctic is a relentless and unforgiving environment with harsh conditions, yet a rich area for feeding in summer. Many sea birds spend the summer in the Arctic for breeding and feeding, attracted by the nutrient-rich water along the coastal areas of Alaska. However, since last year, researchers have noted massive die-offs of common murres (Uria aalge) along the coast. First thought to be a unique event, more and more regions along the coast of Alaska seem to be affected. The latest area with dead birds ashore is Katmai National Park in the southwest corner of Alaska. The scientists are puzzled about the reasons for the die-off.
Federal biologists last week walked 19 ocean beaches along Katmai National Park and counted 2,000 dead seabirds. Most were common murres, a penguin-like bird often found in northern climates. Two common murres had probably died in the last 24 hours, said Robb Kaler of the U.S. Fish and Wildlife Service. The others were weathered or scavenged by eagles, foxes or wolves, indicating they could have died a month or two ago, when large numbers of apparently starved murres also were found in Prince William Sound. Kaler called the Katmai count "pretty darn conservative." With so much time elapsed, Kaler said, it's likely that other carcasses were washed away or carried off by scavengers. "We talk about retention and deposition onto these beaches. What we're finding there can probably only be a hint of what probably was there," Kaler said.
The Alaska population of common murres is 2.8 million. They can dive to 600 feet hunting fish or krill, and they are usually found well offshore in winter. Abnormal numbers of dead murres, all showing signs of starvation, began washing ashore on in March 2015. As the year progressed, the numbers increased. The deaths of common murres spiked to alarming levels after storms late December. A retired U.S. Geological Survey bird expert, David Irons, in early January found thousands of carcasses near the Prince William Sound community of Whittier. By mid-March, 36,000 dead birds had been counted. Researchers have not determined a cause for the deaths, and so far they have found no link to disease or algae toxins. A third year of warm Pacific surface temperatures has been suggested as a contributor or a possible factor in a decline of murre prey. Severe storms could also have killed birds already weakened by something else.
Common murre die-offs have occurred before but not for this long for over such a wide area. The count at Katmai adds to the phenomenon. "The take-home is that every beach we looked at had dead birds on it, pretty evenly distributed," Kaler said. He and retired U.S. Geological Survey biologist Tony DeGange surveyed about 10.5 miles of beach within a 68-mile stretch of coast. Carcasses were found as far as 75 yards from the ocean. Kelp, beach debris and sand covered others. "I'm sure if we had rakes we would have found a lot more," DeGange said. Kaler and DeGange accompanied a National Park Service team conducting a survey of live marine mammals and birds in near-shore waters. Similar March surveys in 2009 and 2012 counted zero and 14 common murres, said Heather Coletti, a Park Service marine ecologist. Last week she counted hundreds. "It's a big change in their distribution," she said.
At Kukak Bay, the survey recorded 12 to 15 humpback whales, 200 Steller sea lions, glaucous-winged gulls and hundreds of murres that should have been far from shore. "There's clearly food in the water and a lot of animals were concentrating there," she said. "I don't know if it's common or not, but it was a really unique sighting."
Source: Dan Joling, Associated Press / Alaska Dispatch News