Vancouver, Canada (SPX) Feb 24, 2011
Predatory fish such as cod, tuna, and groupers have declined by two-thirds over the past 100 years, while small forage fish such as sardine, anchovy and capelin have more than doubled over the same period, according to University of British Columbia researchers.
Led by Prof. Villy Christensen of UBC's Fisheries Centre, a team of scientists used more than 200 marine ecosystem models from around the world and extracted more than 68,000 estimates of fish biomass from 1880 to 2007. They presented the findings at the American Association for the Advancement of Science (AAAS) Annual Meeting in Washington, DC.
Their finding of the simultaneous decline of predatory fish and increase of forage fish provides the strongest evidence to date that humans are indeed "fishing down the food web" and impacting ecosystems globally. The UBC team also found that of the decline in predatory fish population, 54 per cent took place in the last 40 years alone.
"Overfishing has absolutely had a 'when cats are away, the mice will play' effect on our oceans," said Christensen, a professor in the UBC Fisheries Centre. "By removing the large, predatory species from the ocean, small forage fish have been left to thrive."
While the doubling of forage fish amounts to more fish production, Christensen cautioned that the lower trophic-level food web is more vulnerable to environmental fluctuations.
"Currently, forage fish are turned into fishmeal and fish oil and used as feeds for the aquaculture industry, which is in turn becoming increasingly reliant on this feed source," said Christensen. "If the fishing-down-the-food-web trend continues, our oceans may one day become a 'farm' to produce feeds for the aquaculture industry. Goodbye, wild ocean!"
Christensen's presentation was part of an experts' panel to answer the question "2050: Will there be fish in the ocean?" The panel predicted that while there would be fish in 2050, it would consist mostly of the smaller variety.
Share This Article With Planet Earth
University of British Columbia
Water News - Science, Technology and Politics
Washington (AFP) Feb 23, 2011
The world's coral reefs could be wiped out by 2050 unless urgent action is taken to stop threats posed to the "rainforests of the sea" by everything from overfishing to climate change, a report warned Wednesday. Warmer seas caused by global warming; ocean acidification blamed on carbon dioxide pollution; shipping, overfishing, coastal development and agricultural runoff all pose a threat to ... read more
Makeshift toilets part of life in quake-hit city|
Chile survivors live in squalor a year after quake
Insurer Allianz sees ops profit of 8 bln euros this year
Better Mapping Of Human Settlements Supports Disaster Management
Plants That Can Move Inspire New Adaptive Structures
Dell plans China expansion: state media
Japan's NEC in LCD tie-up with China's Tianma
Apple stockholders keep CEO succession plan private
California water future called 'bleak'
Brown Tide Culprit Sequenced: Genome Of The First Of Algal Bloom Species
Oldest Water On Earth
Fishing Down Food Web Leaves Less Big Fish, More Small Fish
Old Salt Suggests Marine Life Is Capturing More Carbon
Climate change halves Peru glacier: official
Carbon Sink At South Pole Has Grown Recently
Massive iceberg shears off glacier after quake hit
Transitioning To Organic Farming
Applications for modified animals debated
High food prices threaten seething Mideast
Examining Climate Change Effects On Wheat
NZealand says one-third of quake city faces demolition
New Zealand earthquake toll surges to 145 dead
Mud volcano set to erupt for quarter-century - scientists
No signs of life as NZ quake toll rises to 113
Ivory Coast envoy reports for duty
New 'environment governance' on agenda in Nairobi
Nigerian troops uncover weapons cache
Three soldiers killed by Casamance rebels: military source
Men's cosmetics take off in China
Remains of Ice Age child found in Alaska
Study: Low self-esteem increases bias
Testing The Limits Of Where Humans Can Live
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement|