Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shopping list gets longer – not less choosy– in some of world’s largest fisheries

15.02.2006


When fishing boats return with catches of increasingly less-valuable fish, the commonly held notion is that the more valuable species have been fished out. This, however, wasn’t true in two-thirds of the world’s large marine ecosystems selected for study by University of Washington researchers.

Instead, the composition of what was landed changed because fishermen chose to target additional kinds of fish. Landings of the more valuable fish remained the same, or even increased, but that may not be sustainable if managers can’t come up with effective strategies, says Timothy Essington, UW assistant professor of aquatic and fishery sciences. Results of the National Science Foundation-funded project appear this week in the Proceedings of the National Academy of Sciences.

"We shouldn’t remain preoccupied with the model of fishing down the food web that assumes the largest, most valuable fish have disappeared," Essington says. "That ignores both what’s happening in the majority of cases as well as the need to manage conflicting demands on ecosystems. These multiple impacts may be sustainable during the initial phases of fisheries development but can ultimately lead to collapse of the higher-value stocks if fisheries develop unchecked and without considering these interactions.



"Navigating these conflicts is moving to the forefront of contemporary marine fisheries management and conservation." Fishing down the food web emerged as a concern in the late 1990s when Daniel Pauly of the University of British Columbia published findings that global landings of fish were shifting from species higher in the food chain, such as halibut and tuna, to those lower in the food chain, such as herring and anchovies.

Pauly, who reviewed the paper for the authors before it was submitted to editors of the Proceedings of the National Academy, developed the method to compare food-web – or trophic – levels of what is landed. The approach considers only what is brought to shore and does not measure how many fish of various species are actually available.

Using Pauly’s method, Essington and UW graduate students Anne Beaudreau and John Wiedenmann, both co-authors on the paper, looked at data between 1950 and 2001. They found the trophic level was shifting downward for landings in 30 of the 48 large marine ecosystems in the world for which they could obtain reliable information. In a little more than two-thirds of those cases – 21 of the 30 ecosystems – the composition of the catch changed to include fish from lower trophic levels, yet the amount of fish from the higher trophic levels remained the same or increased.

Because the research considered only landings, the scientists can’t say if the stocks are plentiful or if the amounts were high for some other reason, such as an increase in the number of boats fishing the area.

In either case, Essington says, "We can’t ignore the policy implications of this common mechanism of sequentially adding species to what is being fished."

In the other nine of the 30 ecosystems the researchers found that high-trophic-level fish were, indeed, disappearing and forcing fishermen to turn to fish lower on the food web. The most spectacular example is the ecosystem in the North Atlantic where fishery collapses are common.

Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>