Featured Research

from universities, journals, and other organizations

Shopping List Gets Longer -- Not Less Choosy -- In Some Of World's Largest Fisheries

Date:
February 22, 2006
Source:
University of Washington
Summary:
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.

Tim Essington and a fishing boat crew member remove fish from nets.
Credit: Image courtesy of University of Washington

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.



Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University of Washington. "Shopping List Gets Longer -- Not Less Choosy -- In Some Of World's Largest Fisheries." ScienceDaily. ScienceDaily, 22 February 2006. <www.sciencedaily.com/releases/2006/02/060215225431.htm>.
University of Washington. (2006, February 22). Shopping List Gets Longer -- Not Less Choosy -- In Some Of World's Largest Fisheries. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2006/02/060215225431.htm
University of Washington. "Shopping List Gets Longer -- Not Less Choosy -- In Some Of World's Largest Fisheries." ScienceDaily. www.sciencedaily.com/releases/2006/02/060215225431.htm (accessed August 27, 2014).

Share This




More Plants & Animals News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Firefighters Rescue Puppy Stuck in Tire

Raw: Firefighters Rescue Puppy Stuck in Tire

AP (Aug. 26, 2014) It took Houston firefighters more than an hour to free a puppy who got its head stuck in a tire. (Aug. 26) Video provided by AP
Powered by NewsLook.com
Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Newsy (Aug. 26, 2014) A study published in the journal "Neurology" interviewed more than 19,000 people and found 15 percent suffer from being "sleep drunk." Video provided by Newsy
Powered by NewsLook.com
Great White Shark Spotted Off Massachusetts Coast

Great White Shark Spotted Off Massachusetts Coast

Reuters - US Online Video (Aug. 26, 2014) A great white shark is spotted off the shore at Duxbury beach in Massachusetts forcing beach goers out of the water. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Raw: Elk Wanders Into German Office Building

Raw: Elk Wanders Into German Office Building

AP (Aug. 25, 2014) A young bull elk wandered inside the office building of a company in Dresden, Germany on Monday. The elk became trapped between a wall and glass windows while rescue workers tried to rescue him safely. (Aug. 25) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins