"Red Devil" squid, jellyfish Plague point to ocean upsets
Pastor Dale Morgan
"Red Devil" squid, jellyfish Plague point to ocean upsets*
21 Aug 2006 01:02:13 GMT
Source: Reuters
(This story is one of two issued today looking at how global warming and
other threats affect the world's oceans)
By Alister Doyle, Environment Correspondent
OSLO, Aug 21 (Reuters) - South American "Red Devil" squid found off
Alaska and jellyfish plaguing the Mediterranean may point to vast
disruptions in the seas linked to global warming, pollution or
over-fishing, experts say.
Fish such as salmon and mackerel have also been spotted in the Arctic,
far north of their normal ranges, in a possible vanguard of wrenching
billion-dollar shifts in world fish stocks this century caused by
warming oceans.
"There will be some places where ocean productivity will increase," said
Ron O'Dor, senior scientist of the Census of Marine Life, a 10-year
project in more than 70 nations to map the diversity of the oceans.
"The story of global warming is going to be good for some people and bad
for others," he added.
Many scientists say that gases emitted by burning fossil fuels -- coal,
gas and oil -- are blanketing the planet and driving up temperatures,
threatening to spur more floods, heatwaves, erosion and rising sea levels.
Warmer oceans are likely to add to older marine threats such as
pollution and over-fishing and upset the habitats of everything from
crabs and Mediterranean jellyfish to "Red Devil" squid and whales.
As species shift, tropical regions, or almost enclosed seas such as the
Mediterranean where fish cannot swim far if the water gets uncomfortably
warm, may be among the most vulnerable.
"Areas close to the equator will most likely be the losers while the
northern or southern areas might be the winners," said Harald Loeng,
head of research in oceanography and climate at the Norwegian Institute
of Marine Research.
"It's most likely that some of the species in the North Sea like cod
will move north ... and be replaced by anchovies and sardines," he said.
Some studies suggest that the Arctic sea ice, for instance, could melt
in summers by 2100. As ice recedes, the extra heat and sunlight will
help plankton grow and so feed more fish.
ON THE MOVE
Humboldt or "Red Devil" squid, which can weigh 40-50 kg (88-110 lb) and
originated off Peru, were caught off Alaska for the first time last year
after sweeping north, O'Dor said.
Around the same time, other scientists found specimens of the jumbo
squid, growing up to about 2 metres (6 ft 7 in) long, in southern Chile.
Over-fishing of more valuable fish stocks might be partly to blame for
the squid population explosion by upsetting the food chain along the
Pacific coast of the Americas.
"As you remove the really big predatory fish like the big tuna and the
marlin and the swordfish there are no predators in the water that can
eat something as big as a 40 kg squid, except a few whales," O'Dor said.
And a spate of jellyfish stinging holidaymakers on Mediterranean beaches
this summer, for instance, may be part of wider changes such as global
warming, or merely a freak.
The boom could be linked to a decline of predators such as turtles
because of pollution -- turtles sometimes choke on plastic bags which
they apparently mistake for billowing jellyfish floating in the water.
And salmon have been caught north of the Bering Straits between Russia
and the United States in recent years. They have also swum from the
north Atlantic to once icy seas off northern Canada.
RISING SEAS
"It seems pretty clear that (the salmon in the Arctic) has to be climate
change. The conditions there have never been suitable for these animals
before," said O'Dor.
Among other changes, tropical coral reefs could die off in warmer
waters. Many reefs, often known as "nurseries of the seas" are
struggling with higher temperatures.
And U.N. studies project that global sea levels could rise by 9 to 88 cm
(3.5 to 34.6 inches) by 2100. That could cut the amount of sunlight
reaching slow-growing corals, which co-exist with light-dependent algae.
Meanwhile, a slightly more acid sea linked to a build-up of greenhouse
gases in the atmosphere could make it harder for creatures like lobsters
or oysters to form shells. They might end up too soft and vulnerable to
predators.
Still, fish stocks have often varied mysteriously.
In 1599, for instance, herring failed to appear along the Norwegian
coast. The locals widely believed that God was unhappy because of
thieving, drunkenness and fighting among fishermen.