Le thon en voie d'extinction à cause du sushi.....

[Animal 0]

Torrid times for the threatened tuna :evil: :evil: :evil: :evil:

Taste for sushi is driving them to extinction

The Gazette, May 8, 2005

For sushi aficionados, the essence of the Atlantic bluefin tuna is its
fat-laced, butter-soft belly meat, called toro. For the long-liners, purse
seiners, harpooners, trappers and fish farmers who seek the bluefin from
Cape Hatteras to the frigid waters south of Iceland to the balmy
Mediterranean, the fish are a bonanza, with choice specimens fetching
$50,000 or more in Tokyo.

But the intensifying trade in bluefin may soon empty the waters of this
master of the sea.

In just the last 35 years, exploding markets for sushi-grade tuna, combined
with intensifying industrial-scale hunts aided by satellites and airplanes,
have devastated not only the fish but also many fisheries.

Dozens of Mediterranean towns that maintained coastal net traps for half a
millennium or more are turning away from now-barren waters. Anglers off New
England, who once watched great parading schools of bluefin migrate north at
the end of each summer, now scour the seas for scattered fish. Most
vulnerable, by far, marine biologists say, is the apparently distinct
population of bluefin tuna that breeds in the Gulf of Mexico.

The threat to the bluefin was underscored last week by researchers who have
tracked hundreds of the fish on their ocean-spanning journeys using
electronic tags. They found that the tuna that spawn in the west, which are
most severely depleted, are further threatened by an ever-broadening gantlet
of hooks, seines, harpoons, traps and now farm-style pens, in which netted
fish are raised and fattened – all to supply the Japanese sushi trade.

Barbara Block, a marine biologist at Stanford University and the lead author
of a study published in Nature, said she found it hard to believe that « a
fish of this size and beauty, an animal that had captured the hearts of
fishermen and scientists alike for millennia, is slipping off Earth. »

The bluefin, known to biologists as Thunnus thynnus, is a wonder of
metabolic and evolutionary perfection, a Ferrari-like mix of refinement and
brute power.

Adult bluefins, some topping half a ton and living 40 years, slice through
icy or tropical waters while maintaining their body temperature around 26C.

Their physiology allows their ruby-red muscles to generate a split-secoind
tail flick, rocketing the fish to on-ramp speeds in pursuit of prey. But
having an oceanic range may also be their undoing, exposing them to harvests
at every turn.

Block has been studying the physiology and behaviour of tunas for 25 years –
more than two of them spent at sea, surgically implanting tags in thrashing
giants hauled briefly onto the decks of sport and commercial fishing boats
assisting in her research.

From her base next to the Monterey Bay Aquarium, which helps support her
work, she leads a research team that focuses on every facet of the bluefin,
from its evolution, genetics and unique muscle physiology to diet and
migrations.

The new study is based on the research team’s decade-long effort to implant
hundreds of sophisticated electronic tags in the giant fish, an enterprise
that is beginning to reveal in new detail their ocean paths, from feeding
grounds along the East Coast and frigid waters south of Iceland to spawning
areas in the balmy Gulf of Mexico and Mediterranean.

Most tagging studies provide only two data points – the place and time of
release and the place and time of capture. In this study, 772 fish were
tagged with sophisticated devices that continually record body and water
temperature, depth and daylight. Some tags stayed in the fish until they
were caught, often for years. Others were intended to break a tether, pop
to the surface, and relay stored data to satellites.

In all, 330 tags provided unparalleled records of fish as they repeatedly
dived thousands of feet, traversed the ocean in a few weeks, and routinely
crossed imaginary lines drawn nearly 25 years ago by tuna-fishing nations to
divvy up what were thought to be separate eastern and western populations.

In the study, Block’s team showed that there indeed appear to be distinct
populations of bluefin that spawn either in the Gulf to the west or the
Mediterranean to the east.

But when the fish disperse across the Atlantic to feed, they mingle,
rendering the management boundary, which runs along the 45th meridian,
relatively meaningless.

There are signs that the accumulated scientific evidence is starting to sway
some members of the International Commission for the Conservation of
Atlantic Tunas, created in 1969 to oversee the fishery.

For two decades, many marine biologists have criticized the organizaiton for
setting quotas too high and for favouring data and analyses provided by the
industry.

Masanori Miyahara, the chairperson of the commission and a senior fisheries
official from Japan, acknowledged that the existing system had failed.

A meeting of scientific advisers to the commission will take place next
month to consider new ways to manage the fish stocks. Miyahara added that
Japan was particularly committed to restoring the bluefin.

« We feel some responsibility for this mess, » he said.

« Japanese buyers are running all around the world and buying as many fish
as possible, particularly bluefin. »