News

    Decline of Big Fish Upsets Ocean Balance

    More prey and fewer predators could throw the ecosystem out of balance

    Experts estimate that predatory fish, the large fish that eat other fish, have declined by two-thirds in the last 100 years.
    Experts estimate that predatory fish, the large fish that eat other fish, have declined by two-thirds in the last 100 years.

    Multimedia

    Audio
    Rosanne Skirble

    By 2050, small fish could dominate the oceans because of the rapid decline of larger, predator fish.

    In a new report, the U.N. Food and Agriculture Organization finds that one-third of the world’s fisheries are overexploited, depleted or recovering and in urgent need of rebuilding. At a recent meeting of the American Association for the Advancement of Science meeting in Washington, University of British Columbia fisheries expert Villy Christensen predicted the eventual preponderance of small fish.

    Twenty years ago, Christensen designed a computer tool called Ecopath to study complex marine ecosystems. Now Ecopath has 6,000 users in 155 countries.

    Christensen used 200 marine models from the Ecopath database for the analysis released at the Washington meeting. "We are estimating that the predatory fish, the large fish that eat other fish, have declined by two-thirds in the 100 years and the decrease is accelerating. In the last 40 years alone, 54 percent of that decline occurred."

    Over the same 100-year period, Christensen says, prey fish like anchovies, herring and sardines have more than doubled. "We’ve never had numbers like that before. We expected it might be the case, now we have numbers documenting it. What has happened here really is that we’ve changed the wild ocean. We’ve removed the big fish."

    More prey and fewer predators could throw the ecosystem out of balance, Christensen says. That could promote the growth of alga blooms which deplete oxygen in the water column. Christensen fears that marine animals and plants would then begin dying off in huge numbers.  "If we look ahead we are going to see less stable ecosystems in the oceans. There would be forage fish and very few of the organisms that control our ecosystem. We need the predators to keep the populations healthy of all the prey fish. That will continue unless we change the way we manage the oceans."

    What’s driving these trends? Jacqueline Alder, coordinator of the Marine and Coastal Ecosystem Branch of the United Nations Environment Program, believes it is overfishing and pollution, complicated by global climate change. She says the future health of the ocean depends on fishing less, reducing wasteful by-catch, and taking action on multiple threats to marine ecosystems.

    "We need to think about expanding our marine protected area systems and also better management of those systems, reducing pollution, reducing the amount of nutrients coming in, including things like agricultural runoff." Alder adds that managers must consider restoring mangroves and coral reefs, "making it so those nursery ecosystems have fish that will grow up into adults that will be available for the fishing community in 2050."

    Eating more prey than predators could help restore a healthy balance to the ocean ecosystem.
    Eating more prey than predators could help restore a healthy balance to the ocean ecosystem.

    Fish now provide more than three billion people with at least 15 percent of their animal protein diet. According to the U.N. Food and Agriculture Organization, fish farms are set to overtake wild ocean catch as the primary source of food fish. Villy Christensen says the aquaculture industry currently relies on a variety of prey fish to feed its farm-raised species and that practice is not conducive to a healthy ocean. "Instead of fishing down the food web we have to eat down the food web. We need to eat the sardines and anchovies."

    Christensen suggests that by changing our eating habits - eating more prey than predators - we could help restore a more healthy balance to the ocean ecosystem.

    This forum has been closed.
    Comments
         
    There are no comments in this forum. Be first and add one

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    German Artists to Memorialize Refugees With Life Jacket Exhibiti
    X
    Hamada Elsaram
    February 05, 2016 4:30 PM
    Sold in every kind of shop in some Turkish port towns, life jackets have become a symbol of the refugee crisis that brought a million people to Europe in 2015.  On the shores of Lesbos, Greece, German artists collect discarded life jackets as they prepare an art installation they plan to display in Germany.  For VOA, Hamada Elrasam has this report from Lesbos, Greece.
    Video

    Video German Artists to Memorialize Refugees With Life Jacket Exhibit

    Sold in every kind of shop in some Turkish port towns, life jackets have become a symbol of the refugee crisis that brought a million people to Europe in 2015.  On the shores of Lesbos, Greece, German artists collect discarded life jackets as they prepare an art installation they plan to display in Germany.  For VOA, Hamada Elrasam has this report from Lesbos, Greece.
    Video

    Video E-readers Help Ease Africa's Book Shortage

    Millions of people in Africa can't read, and there's a chronic shortage of books. A non-profit organization called Worldreader is trying to help change all that one e-reader at a time. VOA’s Deborah Block tells us about a girls' school in Nairobi, Kenya where Worldreader is making a difference.
    Video

    Video Genius Lets World Share Its Knowledge

    Inspired by crowdsourcing companies like Wikipedia, Genius allows anyone to edit anything on the web, using its web annotation tool
    Video

    Video Former Drug CEO Martin Shkreli Angers US Lawmakers

    A former U.S. pharmaceutical business executive has angered lawmakers by refusing to explain why he raised the price of a life-saving pill by 5,000 percent. Martin Shkreli was removed from a congressional hearing on Thursday after citing his Fifth Amendment right to stay silent. Zlatica Hoke has more.
    Video

    Video Super Bowl TV Commercials are Super Business for Advertisers

    The Super Bowl, the championship clash between the two top teams in American Football, is the most-watched sporting event of the year, and advertisers are lining up and paying big bucks to get their commercials on the air. In fact, the TV commercials during the Super Bowl have become one of the most anticipated and popular features of the event. VOA's Brian Allen has a sneak peek of what you can expect to see when the big game goes to commercial break, and the real entertainment begins.
    Video

    Video In Philippines, Mixed Feelings About Greater US Military Presence

    In the Philippines, some who will be directly affected by a recent Supreme Court decision clearing the way for more United States troop visits are having mixed reactions.  The increased rotations come at a time when the Philippines is trying to build up its military in the face of growing maritime assertiveness from China.  From Bahile, Palawan on the coast of the South China Sea, Simone Orendain has this story.
    Video

    Video Microcephaly's Connection to Zika: Guilty Until Proven Innocent

    The Zika virus rarely causes problems for the people who get it, but it seems to be having a devastating impact on babies whose mothers are infected with Zika. VOA's Carol Pearson has more.
    Video

    Video Solar Innovation Provides Cheap, Clean Energy to Kenya Residents

    In Kenya, a company called M-Kopa Solar is providing clean energy to more than 300,000 homes across East Africa by allowing customers to "pay-as-you-go" via their cell phones. As Lenny Ruvaga reports from Kangemi, customers pay a small deposit for a solar unit and then pay less than a dollar a day to get clean energy to light up their homes or businesses.
    Video

    Video Stunning Artworks Attract Record Crowds, Thanks to Social Media

    A new exhibit at the oldest art museum in America is shattering attendance records. Thousands of visitors are lining up to see nine giant works of art that have gotten a much-deserved shot of viral marketing. The 150-year-old Smithsonian American Art Museum has never had a response quite like this. VOA's Julie Taboh reports.
    Video

    Video Apprenticeships Put Americans on Path Back to Work

    Trying to get more people into the U.S. workforce, the Obama administration last year announced $175 million in grants towards apprenticeship programs. VOA White House correspondent Aru Pande went inside one training center outside of Washington that has gained national recognition for helping put people on the path to employment.
    Video

    Video New Material May Reduce Concussion Effects

    As the 2016 National Football League season reaches its summit at the Super Bowl this coming Sunday (2/7), scientists are trying to learn how to more effectively protect football players from dangerous and damaging concussions. Researchers at Cardiff and Cambridge Universities say their origami-based material may solve the problem. VOA’s George Putic reports.
    Video

    Video Saudi Arabian Women's Sports Chip Away at Stereotypes

    Saudi Arabian female athletes say that sports are on the front line of busting traditions that quash women’s voices, both locally and internationally. In their hometown of Jeddah, a group of basketball players say that by connecting sports to health issues, they are encouraging women and girls to get out of their homes and participate in public life. VOA’s Heather Murdock reports.
    Video

    Video A Year Later, Fortunes Mixed for Syrians Forging New Lives in Berlin

    In April of last year, VOA followed the progress of six young Syrian refugees -- four brothers and their two friends -- as they made their way from Libya to Italy by boat, and eventually to Germany. Reporter Henry Ridgwell caught up with the refugees again in Berlin, as they struggle to forge new lives amid the turmoil of Europe's refugee crisis.
    Video

    Video Zika Virus May be Hard to Stop

    With the Zika virus spreading rapidly, the World Health Organization Monday declared Zika a global health emergency. As Alberto Pimienta reports, for many governments and experts, the worst is yet to come.