the bering sea snow crab season
was canceled this year after
billions of crabs disappeared,
devastating Alaska's commercial
fishing industry, and the
livelihoods of those who depend
on it.
From Alaska public media and
kmxt in kodiak, Kirsten dobroth
reports fishermen and
researchers are working to
figure out what happened.
Her story was produced in
collaboration with nova with
major support from the
corporation for public
broadcasting.
Kirsten: The snow crab
population crashed in Alaska.
But why?
More than 10 billion snow crabs
disappeared in 2022, devastating
a commercial fishing industry
worth $200 million the year
before.
Now, researchers are working to
figure out what happened.
And they think warmer ocean
water could be to blame.
The snow crab population in the
bering sea off the western coast
of Alaska has fluctuated for
decades.
An increase in young crabs back
in 2018 led to optimism that
fishing would rebound, but the
hope was short-lived.
>> It was just very poor
fishing.
We searched for miles and miles
and miles and really didn't see
anything.
Kirsten: Gabriel prout and his
family own the silver spray in
kodiak, Alaska.
He says it was obvious something
was wrong the last few years.
The bering sea fishing grounds
are usually covered in sea ice
in the winter.
But there wasn't much ice, and
they fished further north than
usual.
Finding snow crabs was still
difficult.
The lack of sea ice was a red
flag for scientists like Erin
Fedewa, who is studying the
conditions in the bering sea
that led to the massive die-off.
>> That was an immediate
potential smoking gun when we
saw this arctic species suddenly
in decline.
Kirsten: That's because sea ice
is an important ingredient in
the snow crabs' life cycle.
In the winter, it accumulates on
the water's surface.
And during the summer, the ice
melts, sending cold, dense water
sinking to the ocean floor,
where it hovers just above
freezing at around 35 degrees.
Scientists call it the cold
pool.
And it's a sanctuary for young
crabs.
Warmer temperatures can lead to
starvation, and higher rates of
disease.
At the kodiak fisheries research
center, state and federal
researchers are piecing together
how all those factors
contributed to the crabs'
collapse.
Tanks filled with seawater
pumped in from the bay replicate
conditions on the seafloor.
>> And then we can hold the
different portions of the same
population in, say, five degrees
celsius, eight degrees celsius.
And we can begin to look at the
response of those species once
they're in these warmer
temperatures.
Kirsten: Scientists use the
pools to study how different
temperature and ph levels affect
the crabs' development, how fast
they grow and how quickly they
die.
In a separate, smaller tank,
researchers hook up monitoring
equipment to individual crabs
and track their breathing in
different conditions.
They also take blood samples.
>> We know that increases in
temperature increase metabolic
rates of fish and crab, causing
them to need to eat more and
more.
Kirsten: In a shrinking cold
pool, that means more crabs
pushed into the smaller space,
fighting for less food.
Across the hall from the federal
lab, Ben Daly is also trying to
figure out how a smaller cold
pool affects crabs in the bering
sea.
>> That's part of what we're
doing now is trying to untangle
the "What happened" part.
That's only half of the
challenge.
The other half of the challenge
is what do we do next.
Kirsten: Daly and his team have
been tagging crabs in the wild
with satellite transponders that
will track their movement over
time.
He's hoping the tags provide
more detailed information about
the distribution of crabs across
the cold pool.
And this winter, a group of
state and federal researchers
are heading out on the silver
spray to continue studying
bering sea crab populations
outside the lab.
Gabriel prout and his family are
grateful for the work.
The many fishers that rely on
snow crabs for income are left
with more questions than answers
right now.
>> We're sitting tight trying to
count our pennies and figure out
how to make our way forward.
Kirsten: Scientists say it will
likely take years before the
snow crab population rebuilds.
If another marine heatwave hits
the bering sea, it could be even
longer.
But they're hopeful that lessons
learned from snow crabs might
provide insight into how other
marine species handle climate
change as the ocean warms.
For the "Pbs newshour," I'm