BBC 'Only 50 years left' for sea fish

[Guest guest]

>SCIENCE/NATURE

>

> * 'Only 50 years left' for sea fish *

>There will be virtually no fish or other seafood

>from the oceans by the middle of the century,

>scientists conclude.

>Full story:

>http://news.bbc.co.uk/go/em/-/1/hi/sci/tech/6108414.stm

'Only 50 years left' for sea fish

By Richard Black

Environment correspondent, BBC News website

 

 

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

 

 

Richard.Black-INTERNET

 

Story from BBC NEWS:

http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/6108414.stm

 

Published: 2006/11/02 19:01:25 GMT

 

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