Rewilding the Sea - Feral: Rewilding the Land, the Sea, and Human Life - page 237

When you consider that the sperm whale is just one of several spe-
cies, the southern ocean is just one of several regions and the current
number of leviathans is a fraction of what it once was, it becomes
clear that whales could once have caused the sequestering of great
quantities of carbon, perhaps tens of millions of tonnes every year.
This is enough to make a small but significant difference to the com-
position of the atmosphere. Another paper maintains that during the
twentieth century the whaling industry shifted over 100 million
tonnes of carbon from the oceans to the atmosphere, simply by turn-
ing whales into oil and other products that were burnt or otherwise
oxidized. 21 Allowing whale numbers to recover could be seen as a
benign form of geo-engineering.
The removal of the great sharks, which took place, on the whole,
later than the destruction of the whale population, has had similarly
devastating effects. Caught for their fins or accidentally by nets and
lines set for other species, big sharks have vanished with astonishing
speed. Off the eastern seaboard of the United States, for example, in
the thirty-ive years beginning in 1972, tiger sharks declined by 97 per
cent, scalloped hammerheads by 98 per cent and bull sharks, dusky
sharks and smooth hammerheads by 99 per cent. 22 The result is an
explosion of animals which no other species is big enough to eat:
large rays and skates and smaller sharks. Many of them have increased
tenfold or more. In Chesapeake Bay alone, for example, there are now
an estimated 40 million cownose rays.
Cownose rays eat shellfish, and this population consumes some
840,000 tonnes a year - almost 3,000 times as much as the total land-
ing of clams of all descriptions in Virginia and Maryland. 23 By
2004 they had wiped out North Carolina's scallop fishing industry
and were rapidly doing the same for oysters, hard clams and softshell
clams. The economic damage caused by the destruction of large sharks
surely outweighs any money made by catching them.
The collapse of the cod shoals off north-eastern America has had
the opposite effect. Released from their predators, commercially valu-
able shellfish - in this case, shrimps, crabs and lobsters - have
exploded, creating a new industry as valuable as the one it replaced.
These too are now being heavily exploited. 24 Regardless of the eco-
nomic consequences, the destruction of one of the world's great