Oceans in Crisis - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 165

and often are closer to 99 per cent. A number of species, including
iconic forms such as the hammerhead, are at real risk of extinction.
Many of the sharks have been taken just for their fins, for the famous
soup (for which the fins only add a gelatinous texture, while the
taste comes from nothing more exotic than chicken broth). It is
extraordinary that a culinary quirk can have such an effect on the
biology of the Earth.
A little farther down the food chain, historical accounts painted a
picture of astonishing abundance of the Atlantic cod off Newfound-
land. Fish catches, high throughout the twentieth century, peaked in
a burst of high-intensity fishing in the 1970s, then crashed in the 1990s
as the fish effectively disappeared, collapsing to less than 1 per cent of
its (pre-baseline) population. It still has not recovered, not least
because of a predator-prey reversal: the now-scarce young cod are
being eaten by the forage fishes and invertebrates that used to be
hunted by the abundant mature cod of past times. 93 Remarkably, Jules
Verne predicted the Newfoundland cod collapse in his classic under-
water adventure 20,000 Leagues Under the Sea. 94
Living in deep waters these days affords little protection. Five spe-
cies of commercially exploited deep-sea grenadiers, skates, and eels
were assessed at the end of the twentieth century. In the 17 previous
years, population declines ranged from 87 per cent to 98 per cent. 95
The story across the seas is depressingly consistent. Most fish
stocks are being overfished, some to the point of functional extinc-
tion. It is understandable: fish is a wonderful source of protein, and
there are ever more hungry human mouths to feed (and ever more
powerful and technologically enhanced fishing fleets). The ecologi-
cal structure of the ocean is being altered, too, for one cannot remove
the top parts of a food web without the effects rippling through to
the levels below. 96
It is not just the sea, though—the sea floor, too, is being refashioned.