Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Earth Science News .




WATER WORLD
Predictions of climate impacts on fisheries can be a mirage
by Staff Writers
San Diego CA (SPX) Mar 28, 2013


File image.

In the early 1940s, California fishermen hauled in a historic bounty of sardine at a time that set the backdrop for John Steinbeck's "Cannery Row" novel. But by the end of the decade the nets came up empty and the fishery collapsed. Where did they all go? According to a new study led by scientists at Scripps Institution of Oceanography at UC San Diego, the forces behind the sardine mystery are a dynamic and interconnected moving target.

Publishing in the Proceedings of the National Academy of Sciences, Scripps graduate student Ethan Deyle, professor George Sugihara, and their colleagues argue that problems lie in seeking answers one factor at a time, as scientists have done for decades. What is the impact of climate on sardines? What is the effect of overfishing on sardines? Focusing on single variables in isolation can lead to misguided conclusions, the researchers say.

"Studying ecosystems in this piecemeal way makes it hard to find quantitative relationships, the kind that are useful for management and stand the test of time," said Deyle.

Instead, using novel mathematical methods developed last year at Scripps, the researchers argue that climate, human actions, and ecosystem fluctuations combine to influence sardine and other species populations, and therefore such factors should not be evaluated independently.

The technique developed by Sugihara and his colleagues, called "convergent cross mapping," takes multiple variables into account and avoids the centuries-old "correlation does not imply causation" issue that has plagued single-factor studies.

For example, based on data from the Scripps Institution of Oceanography Pier, studies in the 1990s showed that higher temperatures are beneficial for sardine production. By 2010 new studies proved that the temperature correlation was instead a misleading, or "mirage," determination.

"Mirages are associations among variables that spontaneously come and go or even switch sign, positive or negative," said Sugihara. "Ecosystems are particularly perverse on this issue. The problem is that this kind of system is prone to producing mirages and conceptual sand traps, continually causing us to rethink relationships we thought we understood."

By contrast, convergent cross mapping avoids the mirage issue by seeking evidence from dynamic linkages between factors, rather than one-to-one statistical correlations.

"Sustainable sardine fishing based on ecosystem-based management should adapt to dynamic changes in the ocean environment, and future policies should incorporate these effects to avoid another 'cannery row,'" said Deyle.

The investigation into the cause of the 1940s sardine collapse spawned the launch of the California Cooperative Oceanic Fisheries Investigations (CalCOFI), one of the world's longest and most valuable marine research programs that continues today with support from Scripps, NOAA's National Marine Fisheries Service (Southwest Fisheries Science Center), and the California Department of Fish and Game.

In addition to Deyle and Sugihara, coauthors of the paper include Michael Fogarty of the National Marine Fisheries Service, Northeast Fisheries Science Center; Chih-hao Hsieh of National Taiwan University; Les Kaufman of Boston University; Alec MacCall and Stephan Munch of the National Marine Fisheries Service, Southwest Fisheries Science Center; and Charles Perretti and Hao Ye of Scripps.

.


Related Links
University of California - San Diego
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
Researchers Issue Forecast for 'Moderate' New England Red Tide in 2013
Cape Cod MA (SPX) Mar 28, 2013
New England is expected to experience a "moderate" red tide this spring and summer, report NOAA-funded scientists studying the toxic algae that cause blooms in the Gulf of Maine. The "red tide" is caused by an alga Alexandrium fundyense, which produces a toxin that can cause paralytic shellfish poisoning (PSP). Red tide typically occurs annually along some portions of the Gulf of Maine coast. Th ... read more


WATER WORLD
Disasters caused $186 bn in damage last year: Swiss Re

Outside View: Homeless youth awareness

Britain enhancing SAR services

Los Angeles drills response to 7.8 quake

WATER WORLD
Lasers could yield particle research tool

Paint-on plastic electronics: Aligning polymers for high performance

DARPA Envisions the Future of Machine Learning

Removing orbital debris with less risk

WATER WORLD
Scientists confirm first two-headed bull shark

Predictions of climate impacts on fisheries can be a mirage

Researchers Issue Forecast for 'Moderate' New England Red Tide in 2013

Slovenia seeks better water management

WATER WORLD
The long winter ahead

For polar bears, it's survival of the fattest

NASA Begins New Season of Arctic Ice Science Flights

Significant contribution of Greenland's peripheral glaciers to sea-level rise

WATER WORLD
Climate change rewrites world wine list

Pesticides short-circuit bee brains: study

Brazil grocers pledge to shun Amazon meat

Brazil supermarkets to keep Amazon meat off shelves

WATER WORLD
Iceland sees unusual seismic activity at Hekla volcano

Huge and widespread volcanic eruptions triggered the end-Triassic extinction

Two quakes rattle Mexico

Six killed, 11 missing in Indonesian landslide: official

WATER WORLD
China an inspiration for S.Africa, Zuma tells Xi

Call for probe into S.Africa military presence in C.Africa

Sierra Leone sends 850 soldiers to Somalia

China's Xi vows to 'intensify' ties with Africa

WATER WORLD
Urban vegetation deters crime in Philadelphia

Patents said threat to 'genomic liberty'

'End of Men'? Not Even Close, Says UC San Diego Report on Gender in the Professions

Wireless, implanted sensor broadens range of brain research




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