Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




WATER WORLD
Overfishing of small species causes jellyfish curse
by Staff Writers
Paris (AFP) March 19, 2013


Marine biologists say they have proof that excessive trawling of small fish species leads to proliferation of jellyfish, a worsening phenomenon whose causes have been unclear.

The scientists monitored ecosystems in two ocean zones a thousand kilometres (600 miles) apart, traversed by the same current.

One zone was off Namibia, where fishing has been unregulated, and the other was off South Africa, where catches of so-called forage fish -- sardines, anchovies and herrings -- are controlled according to available stocks.

"In the 1960s, the waters off Namibia used to yield 10 million tonnes of sardines annually. This has been replaced by 12 million tonnes of jellyfish," Philippe Cury at France's Institute for Development Research (IRD) told AFP on Tuesday.

"There was very poor management of sardines and anchovies, which were overexploited and have now almost disappeared," said Cury, a co-author of a study that appears in the journal the Bulletin of Marine Science.

"In South Africa, there was very careful management of forage fish stocks, and there has been no jellyfish outbreak."

Experts have fiercely debated the explosive growth in jellyfish populations in many ocean regions.

Suspected culprits have been damage to the seabed ecosystem by bottom trawling; the removal of predator fish that keep the jellyfish population under control; and the greenhouse effect, which is warming the sea.

But Cury said the new research points to the impact of removing a small but important strand in the food web.

With little fish removed from the sea, jellyfish have no competitors for plankton, their source of food. As a result, they proliferate uncontrolled.

"This is why it is essential to keep a certain abundance of forage fish" in the marine mix, said Cury.

.


Related Links
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





WATER WORLD
Discards ban could impact seabirds population
Plymouth UK (SPX) Mar 19, 2013
The European Parliament recently voted to scrap the controversial discards policy, which has seen fishermen throwing thousands of edible fish and fish waste back into the sea because they have exceeded their quotas. Scientists at Plymouth University believe this could have a negative impact on some seabirds, which have become used to following the fishing vessels and are increasingly relia ... read more


WATER WORLD
Lunar Orbiter Image Recovery Project Seeks Public Support To Retrieve Apollo Era Moon Images

China sets moon mission re-entry test

Lunar impacts created seas of molten rock

China to use modified rocket for moon landing mission

WATER WORLD
NASA Curiosity rover back online after memory glitch

Software glitch in NASA Mars rover

Panorama From NASA Mars Rover Shows Mount Sharp

Opportunity Departing South Soon

WATER WORLD
Reproduction In Zero Gravity

Sara Brightman's Space Trip Under Question

Michoud Building LNG Tanks For Lockheed Martin

Technology to detect Alzheimer's takes SXSW prize

WATER WORLD
Shenzhou 10 - Next Stop: Jiuquan

China's fourth space launch center to be in use in two years

China to launch new manned spacecraft

Woman expected again to join next China crew roster

WATER WORLD
New ISS crew prepares for launch

Space crew returns to Earth from ISS

Canadian commands space station for first time

'Goody Bag' Filled With Sample Processing Supplies Arrives on Station

WATER WORLD
Vega receives its upper stage as the next mission's two primary passengers land in French Guiana

Grasshopper Successfully Completes 80M Hover Slam

Musk: 'I'd like to die on Mars'

Ariane 5 vehicle for next ATV resupply mission in Kourou

WATER WORLD
Distant planetary system is a super-sized solar system

Water signature in distant planet shows clues to its formation

The Great Exoplanet Debate

Earth-sized planets in habitable zones are more common than previously thought

WATER WORLD
Videogame power harnessed for positive goals

Europe triples recycling but still lags target

Mobile LIDAR technology expanding rapidly

First Laser Communication System Integrated, Ready for Launch




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement