What
exactly will '08 bring? Launch our gallery for a month-by-month
guide to the biggest stories of the year ahead.
Attack of the
Jellies
A spate of jellyfish invasions is
imperiling crucial fishing grounds, menacing beachgoers, and
threatening coastal economies. Experts want to know why.
It's like a scene from a bad '50s monster flick: Nation
attacked by swarms of poisonous giant jellyfish! But that's
exactly what's happening off the Japanese coast. The
dishwasher-size Nomura's jellyfish, a gelatinous 400-pound
blob with thousands of stinging tentacles, was once uncommon
in Japanese waters. By early 2006, its numbers were estimated
to be in the millions.
Elsewhere in the world, similar stories played out. In
July, a creature called Mnemiopsis inundated Swedish
seas; the invasive species is believed to have hitchhiked into
the northern Atlantic by shipping vessel. And in September,
millions of purple jellies called Pelagia noctiluca
swarmed the Italian coast. The out-of-season visitors
interrupted fishing operations and scared away beachgoers with
their vicious stings.
From Tasmania to Namibia to the Gulf of Mexico, recent
jellyfish invasions have puzzled scientists and devastated
local economies. Closed beaches are the least of the problem.
Jellies have stung farmed salmon, clogged nets on fishing
vessels, even blocked water-intake valves at nuclear power
plants.
"The number of occurrences, their duration and geographical
extent—all of those are exceptional," says University of
Connecticut zoologist Ann Bucklin, who is heading up the count
of zooplankton—marine animals that drift with currents—for the
Census of Marine Life, an international effort to count all
ocean animal species by 2010 (jellyfish are one type of
zooplankton). "It appears to be outside the normal variation
that we've seen in the past," she adds. "The [zooplankton]
blooms seem to be dramatically more severe than they used to
be."
Of all ocean species, jellyfish are among the least studied
by scientists, in part because of their lack of obvious
utility to humans, and in part because of the specific
challenges of working with them. The invertebrates are
difficult to handle, often poisonous, and prone to
disintegrating when caught in nets. Our limited knowledge of
normal jelly habits makes it tough for scientists to pinpoint
what's behind the mysterious trend.
What they do know is that jellies are opportunistic animals
that capitalize quickly on changing conditions. "The more food
you give them, the more jellyfish you get," says marine
biologist Jennifer Purcell, who has studied the connection
between changing environmental conditions and jellyfish
density. Warmer ocean temperatures, increased ocean acidity,
agricultural pollution, and especially a decline in predators
as the result of overfishing are all possible explanations for
the recent jellyfish boom—and reasons why we're likely to see
even more outbreaks this year and in the years to come.
Of course, some people are looking for ways to benefit.
Japanese chefs have begun using jellyfish in more dishes and
even cocktails, and researchers have harvested the animals'
mucus for use in cosmetics. Call it the economy of a more
gelatinous world.—Kalee Thompson
Turn the page to read about the dark side of
the upcoming Olympics.
