ONLY 50 YEARS LEFT FOR SEA LIFE

[Anonymous]

‘Only 50 years left’ for sea fish
There
will be virtually nothing left to fish from the seas by the middle of
the century if current trends continue, according to a major scientific
study.Stocks have collapsed in nearly one-third of sea fisheries, and
the rate of decline is accelerating.Writing in the journal Science, the
international team of researchers says fishery decline is closely tied
to a broader loss of marine biodiversity.

But a greater use of protected areas could safeguard existing stocks.
“The
way we use the oceans is that we hope and assume there will always be
another species to exploit after we’ve completely gone through the last
one,” said research leader Boris Worm, from Dalhousie University in
Canada.”What we’re highlighting is there is a finite number of stocks;
we have gone through one-third, and we are going to get through the
rest,” he told the BBC News website.Steve Palumbi, from Stanford
University in California, one of the other scientists on the project,
added: “Unless we fundamentally change the way we manage all the ocean
species together, as working ecosystems, then this century is the last
century of wild seafood.”

Spanning the seas
This is a vast
piece of research, incorporating scientists from many institutions in
Europe and the Americas, and drawing on four distinctly different kinds
of data.Catch records from the open sea give a picture of declining
fish stocks.In 2003, 29% of open sea fisheries were in a state of
collapse, defined as a decline to less than 10% of their original
yield.Bigger vessels, better nets, and new technology for spotting fish
are not bringing the world’s fleets bigger returns – in fact, the
global catch fell by 13% between 1994 and 2003.Historical records from
coastal zones in North America, Europe and Australia also show
declining yields, in step with declining species diversity; these are
yields not just of fish, but of other kinds of seafood too.Zones of
biodiversity loss also tended to see more beach closures, more blooms
of potentially harmful algae, and more coastal flooding.Experiments
performed in small, relatively contained ecosystems show that
reductions in diversity tend to bring reductions in the size and
robustness of local fish stocks. This implies that loss of biodiversity
is driving the declines in fish stocks seen in the large-scale
studies.The final part of the jigsaw is data from areas where fishing
has been banned or heavily restricted.These show that protection brings
back biodiversity within the zone, and restores populations of fish
just outside.”The image I use to explain why biodiversity is so
important is that marine life is a bit like a house of cards,” said Dr
Worm.”All parts of it are integral to the structure; if you remove
parts, particularly at the bottom, it’s detrimental to everything on
top and threatens the whole structure.”And we’re learning that in the
oceans, species are very strongly linked to each other – probably more
so than on land.”

Protected interest
What the study does not
do is attribute damage to individual activities such as over-fishing,
pollution or habitat loss; instead it paints a picture of the
cumulative harm done across the board.Even so, a key implication of the
research is that more of the oceans should be protected.But the extent
of protection is not the only issue, according to Carl Gustaf Lundin,
head of the global marine programme at IUCN, the World Conservation
Union.”The benefits of marine-protected areas are quite clear in a few
cases; there’s no doubt that protecting areas leads to a lot more fish
and larger fish, and less vulnerability,” he said.”But you also have to
have good management of marine parks and good management of fisheries.
Clearly, fishing should not wreck the ecosystem, bottom trawling being
a good example of something which does wreck the ecosystem.”But, he
said, the concept of protecting fish stocks by protecting biodiversity
does make sense.”This is a good compelling case; we should protect
biodiversity, and it does pay off even in simple monetary terms through
fisheries yield.”Protecting stocks demands the political will to act on
scientific advice – something which Boris Worm finds lacking in Europe,
where politicians have ignored recommendations to halt the iconic North
Sea cod fishery year after year.Without a ban, scientists fear the
North Sea stocks could follow the Grand Banks cod of eastern Canada
into apparently terminal decline.”I’m just amazed, it’s very
irrational,” he said.”You have scientific consensus and nothing moves.
It’s a sad example; and what happened in Canada should be such a
warning, because now it’s collapsed it’s not coming back.”

1. Experiments show that reducing the diversity of an ecosystem lowers the abundance of fish
2.
Historical records show extensive loss of biodiversity along coasts
since 1800, with the collapse of about 40% of species. About one-third
of once viable coastal fisheries are now useless
3. Catch records
from the open ocean show widespread decline of fisheries since 1950
with the rate of decline increasing. In 2003, 29% of fisheries were
collapsed. Biodiverse regions’ stocks fare better
4. Marine reserves
and no-catch zones bring an average 23% improvement in biodiversity and
an increase in fish stocks around the protected area.

[Author]

November 3, 2006 at 1:09 PM