Is it true that some commercial fishing nets are 40 miles
I heard a TV commentator accuse fishing fleets of “strip-mining
the oceans.” If their nets are really that large, it
certainly sounds like that’s what is happening!
— B. Johnson, Port Chester, NY
Considered the most destructive fishing technology ever devised,
commercial “drift netting” involves vertically
suspending near-transparent nylon nets in ocean waters with
floats attached to the top and weights fixed to the bottom.
Some are known to be as much as 50 miles wide, with a vertical
height of about 50 feet deep. Once set, the nets are allowed
to drift with the wind and currents (hence the term “drift
net”) and to snag just about everything in their paths.
Drift netting is considered to be the most efficient way to
catch large amounts of the ocean’s biggest fish, including
tuna, swordfish, marlin and salmon.
The problem with these gigantic nets is that they don’t
discriminate between fish that can be sold for dinner tables
and so-called “by-catch”—marine life not
intended for food but which get hauled up anyway and then subsequently
discarded dead back into the ocean. Drift netting is responsible
not only for killing fish that will never be sold commercially,
but also for the unnecessary death of hundreds of thousands
of dolphins, seals, whales and sea turtles every year, despite
international agreements outlawing the practice.
Driftnets also sometimes break loose, sailing through the oceans
unattended, “ghost fishing” until they sink to
the bottom under the weight of their victims or wash up onshore
where they snag seabirds, seals and other unsuspecting wildlife.
First developed by Japan in the 1970s, drift netting quickly
caught on elsewhere and within just a decade scientists began
to notice that the practice was taking a severe toll on marine
biodiversity. Various experiments were conducted that bore
out these concerns. A 1989 test using driftnets to catch tuna,
for example, killed an average of four and a half marine mammals
in every “set”—one whale or dolphin for every
10 tuna caught. Meanwhile, analysts observed a Japanese boat
kill 59 dolphins and small whales in just 30 sets—a rate
of almost two per set. With commercial fishing fleets legally
deploying some 30,000 miles of driftnets around the world daily
during the 1980s, the toll on marine life was no doubt staggering.
The first major effort to stop drift netting was the Wellington
Convention, which was signed in New Zealand in 1989 and put
into place a driftnet ban in the South Pacific. Four years
later, the United Nations called for an international moratorium
on the practice. Meanwhile, in 1992 Russia, Japan and the United
States created the Convention for the Conservation of Anadromous
Stocks in the North Pacific, banning all driftnets more than
1 1/2 miles in length (“anadromous” refers to fish
like salmon that live in salt water but spawn in fresh water).
South Korea signed on but China did not, though it agreed to
let the U.S. Coast Guard help police its fleet. In 2002, the
European Union banned drift netting by its member countries.
According to Earthtrust, a U.S. nonprofit committed to ending
drift netting, despite such commitments commercial fishing
fleets around the world still deploy tens of thousands of miles
of driftnets on a daily basis. While efforts to stop the practice
have no doubt had some effect, drift netting remains one of
the biggest drivers of over-fishing today. As long as demand
for tuna, salmon and other big fish continues, drift netting—illegal
or otherwise—is likely to continue to wreak havoc on
the world’s marine ecosystems.
CONTACT: Earthtrust’s DriftNetwork, www.earthtrust.org/dnw.html.
Submit questions to firstname.lastname@example.org.