blanketed the ground where the Peary caribou sought to forage, cutting
them off from their food source and causing them to die of starvation.
As Gunn explains it to me: “The caribou expended so much energy try-
ing to dig through the snow and ice to get at the food below that they
just ran out of energy and then they died.”
SEABIRDS INPERIL
In 1997, conditions in the Bering Sea were unusually warm, windless,
and cloud-free. Sea-surface temperatures were the highest ever
recorded. And the ocean’s top layer did not mix well with lower levels,
leading to a rapid depletion of nutrients in the upper layers and the
largest bloom of coccolithophore algae ever seen in the Bering Sea.
That same summer, as many as 200,000 short-tailed shearwaters—
approximately 10 percent of the regional population of this seabird
species—died, apparently of starvation. The birds that survived were
lighter than they had been a year earlier. The events were not coinci-
dental: With light levels lower beneath the bloom, the seabirds may
have had trouble seeing their fish prey. They would likely have had dif-
ficulty reaching them as well, as the warmer temperatures seemingly
prompted the fish to seek refuge in deeper, cooler waters where the
shearwaters could not reach them. The following summer, conditions
had somewhat abated, but the bloom remained, and was large enough
to be photographed by NASA satellites. And there was another mass
mortality of seabirds, this time common murres, tens of thousands of
which died from Cook Inlet west to the Aleutian Islands.
The algal bloom and associated seabird deaths were but the latest
in a series of unusual events and wildlife declines to have struck the
Bering Sea and Gulf of Alaska in recent decades. Several types of fish-
eating birds have undergone declines of as much as 50 percent in
Prince William Sound, although populations of bottom-feeding
birdlife in the same region have remained stable or increased during
that time.
Populations of several species of waterfowl, among them Steller’s
eider, spectacled eider, and various species of loon, have undergone
precipitous declines, sometimes in excess of 50 percent, on their
104 Kieran Mulvaney