84 HARPER’S MAGAZINE / MARCH 2020
delegates from the Antarctic Treaty’s
member nations. Like the treaty, the
success of the CCAMLR has depended
on compromise. Its conservation agen-
da allows for “rational use” of marine
resources, a loophole for commercial
fishing. This past November, the com-
mission failed for the eighth year in a
row to establish a marine preserve in
the Weddell Sea.
A species that doesn’t receive special
treatment in McCann’s book is the
Antarctic toothfish, more commonly
known by its market name, Chilean sea
bass. The few species of fish that can
thrive in the Southern Ocean are
specially equipped: icefish and Antarc-
tic toothfish produce antifreeze in
their blood, and icefish are the only
vertebrates that lack hemoglobin, ab-
sorbing oxygen through their skin.
Both species are fished commercially in
the Ross Sea. Like the rest of the
Southern Ocean’s fauna, the tooth-
fish’s value lay in its crucial adaptation
to the cold. Chefs found its flesh—
laced with fats that make the toothfish
buoyant and able to traverse the water
column without a swim bladder—
impossible to
overcook. It
was introduced
in 1997 as a
delicacy in
American su-
permarkets
and upscale
restau rants.
McCann notes
that the baited
longlines used
to hook tooth-
fish also at-
tract and en-
snare albatross and other seabirds (on
memorable occasions, they have also
hooked colossal squid), though she
doesn’t mention its importance in the
food web as the prey of orcas and
seals, and as a voracious predator in
its own right, the largest fish in an
ocean without sharks.
But the most important link in the
ecosystem of the Southern Ocean—
its “fluttering heart,” in McCann’s
lovely phrase—is a crustacean, about
two and a half inches long, that
grazes on algae and swarms like an
underwater locust.
By some measures,
Antarctic krill
may be the most
abundant living
species: 500 mil-
lion metric tons is
a conservative ap-
praisal of the total
biomass of the
population. Krill
swarms in the
ocean around Ant-
arctica can extend
for miles, and have
been observed at
three miles deep.
They are the linch-
pin of what biolo-
gists call the “wasp
waist” ecosystem
of the Southern
Ocean: many spe-
cies of phytoplank-
ton convert the
sun’s energy into
proteins, and many
large carnivores
rely on a single spe-
cies, krill, to turn
that phytoplank-ton into a movable feast. A blue whale
can eat four tons of krill in a day.
But naturalists in the Antarctic
have long pushed against the charac-
terization of krill merely as whale food.
Ommanney wrote sensually of their
charms in 1938:The “krill” is a creature of delicate and
feathery beauty.... It swims with that
curiously intent purposefulness peculiar
to shrimps, all its feelers alert for a
touch, tremulously sensitive, its protrud-
ing black eyes set forward like lamps.The Scottish biologist James Marr,
in a monumental 1962 treatise, as-
serted that krill, “far from remaining
a passive drifter, has on the contrary
become a creature of great agility,
powers of locomotion, purposeful in-
tent, and not a little awareness.”
With his book from 2018, The
Curious Life of Krill: A Conserva-
tion Story from the Bottom of the
Wo rl d, Stephen Nicol, a krill biolo-
gist at the Institute for Marine and
Antarctic Studies at the University
of Tasmania, continues the work of
his forebears with enthusiasm. His
life’s research has involved track-
ing, catching, and counting an
evasive quarry. Krill defy easy mea-
surement; in lean seasons they
downsize, molting and regrowing
smaller exoskeletons, confounding
estimates of their age (a krill in
captivity named Alan lived as long
as eleven years). But knowing how
many krill are in the Southern
Ocean—and how that number is
changing—is vital to understand-
ing the future of the ecosystem.
The ardor of the Discovery Investi-
gation naturalists had an outcome that
some surely did not intend: krill beganLeft: In the Wake of Scott & Shackleton, 2018, a drawing by Peter Anderson, of a voyage inspired by the
early-twentieth-century expeditions led by Robert Falcon Scott and Ernest Shackleton © The artist
Right: Krill feeding on phytoplankton in the South Atlantic © Paul Nicklen/National Geographic Creative