Oceans in Crisis - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 166

The Ploughed Sea Floor
Catching fish isn't simply a question of casting out a net, or a line with
a baited hook. There are a lot of tasty things that live on the sea floor,
or that burrow in the sea floor sediment, lying in wait for passing prey
or hiding from predators. When it comes to finding food, humans
have always been ingenious. As far back as the fourteenth century,
English fishermen had devised a 'wondyrechaun', a long, heavy iron
bar with a net attached that, towed behind their boats, was dragged
over the seabed. The net was close-meshed so that no fish in its path
'be it ever so small' could escape. It was crude, but effective. The prac-
tice became profitable and popular. It was also damaging, as it wrecked
the oyster beds, ploughed up the sea floor, and fouled the water, kill-
ing off the spat that mature fish fed on. A petition was put to the King,
Edward III, who appointed a commission to look into the problem
(the answer, they suggested, was to move the problem into deeper
water farther offshore). 97
That was only the beginning. Things have moved on since then,
and took a giant step with the widespread adoption of powered fish-
ing vessels in the mid-twentieth century. Now, in terms of propor-
tion, the continental shelf has been more widely ploughed by the
ever-active trawling gear than the land surface has been ploughed by
tractor. The process rakes over the seabed, the bulging nets bringing
up a mass of everything that lives there. The fishermen pick through
the dead and dying organisms, tossing overboard everything that they
don't consider valuable (generally most of the catch) and keeping
those fish that have market value. The oceanographer Sylvia Earle has
likened the practice to bulldozing forests to catch squirrels.
In recent years, the trawlers have moved into ever-deeper waters, to
resculpt the sea floor there. For instance, a certain tasty deep-sea
shrimp, Aristeus antennatus , thrives in the deep waters of the north-west