Ships Bring Alien Jellyfish Invaders To Our Shores

August 16, 2005

Marine environments around the world are being threatened by exotic species of the moon jellyfish being dispersed by international shipping, according to new research.

Using genetic data and computer simulations of ocean currents and water temperatures, researchers from the University of New South Wales and the University of California, Davis, have revealed that the moon jellyfish could not have migrated naturally, according to a report in today's Proceedings of the National Academy of Sciences journal.

By simulating the movement of the jellyfish – of the genus Aurelia – over a 7,000 year period the study provides strong evidence that their world-wide dispersal post-dates European global shipping and trade that began almost 500 hundred years ago.

Recent surveys suggest that up to almost one quarter (23 per cent) of all marine species in international harbours are non-indigenous, according to one of the research authors, Dr Mike Dawson of the University of California, Davis.

"Marine organisms traverse the globe in ballast water, on ship hulls and through the trade of exotic species such as tropical fish and this has potential to displace local marine species, threaten ecosystems and cause billions of dollars in damage and preventive control," says Dawson who tracked the invading jellyfish in Japan, California, western Europe and the east and west Australian coastlines.

Introduced species are believed to cost the United States $122 billion per year. About 3,000 species of marine organisms are believed to travel the world in ships' ballast water each day.

Ships take in water for stability before a voyage and despite preventative measures such as mid-ocean exchange/flushing this 'foreign' water and its contents can find their way into bays and harbours at the destination.

The computer model used to track jellyfish movements could answer similar questions about the migration and introduction of any suspected non-native marine creatures, according to its developers, UNSW oceanographers, Associate Professor Matthew England and Alex Sen Gupta.

"Until now our knowledge of natural and human-assisted dispersal of species has been insufficient to confidently track and predict the spread of non-indigenous marine species," says Professor England.

"Now we have a tool that can include data on currents, geography and the biology of an organism to help separate natural dispersal from that which happens through shipping and trad. It's a pretty sophisticated model and we plan to make it available as a research tool on the World Wide Web."

Discovery: new species of moon jellyfish

The researchers also discovered that there are far more species of moon jellyfish than previously thought.

"We identified 16 species of moon jellyfish, revealing that marine biodiversity is actually much higher than was thought previously," Dr Dawson says, "in retrospect it's easy to see how this wasn't noticed until now.

"When you examine moon jellyfish from locations from around the world they look very similar; it's only when you analyse their DNA as we did, that it becomes obvious that they're very different. This means that traditional methods that compare physical characteristics can benefit from modern techniques such as DNA analysis," he says.

Copyright 2005 by Space Daily, Distributed United Press International

Explore further: Dangerous jellyfish, including man-of-war, off New Jersey

Related Stories

Injured jellyfish seek to regain symmetry, study shows

June 16, 2015

Self-repair is extremely important for living things. Get a cut on your finger and your skin can make new cells to heal the wound; lose your tail—if you are a particular kind of lizard—and tissue regeneration may produce ...

The wonders of bioluminescent millipedes

June 8, 2015

There's something inherently magical, even surreal, about seeing hundreds of glowing millipedes scattered across the ground of a sequoia grove on a moonless night in Sequoia National Park.

Mystery giant jellyfish washes up in Australia

February 6, 2014

Scientists were on Thursday working to classify a new species of giant jellyfish that washed up on an Australian beach, describing it as a "whopper" that took their breath away.

Recommended for you

How bees naturally vaccinate their babies

July 31, 2015

When it comes to vaccinating their babies, bees don't have a choice—they naturally immunize their offspring against specific diseases found in their environments. And now for the first time, scientists have discovered how ...

Binary star system precisely timed with pulsar's gamma-rays

July 31, 2015

Pulsars are rapidly rotating compact remnants born in the explosions of massive stars. They can be observed through their lighthouse-like beams of radio waves and gamma-rays. Scientists at the Max Planck Institute for Gravitational ...

Image: Hubble sees a dying star's final moments

July 31, 2015

A dying star's final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star's demise is still quite ...

Exoplanets 20/20: Looking back to the future

July 31, 2015

Geoff Marcy remembers the hair standing up on the back of his neck. Paul Butler remembers being dead tired. The two men had just made history: the first confirmation of a planet orbiting another star.

Earth flyby of 'space peanut' captured in new video

July 31, 2015

NASA scientists have used two giant, Earth-based radio telescopes to bounce radar signals off a passing asteroid and produce images of the peanut-shaped body as it approached close to Earth this past weekend.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.