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.
    Philadelphia Uses DNC Spotlight to Profile Historic Role in Founding of United Statesi
    X
    July 28, 2016 2:16 AM
    The slogan of the Democratic National Convention now underway in Philadelphia is “Let’s Make History Again” which recognizes the role the city played in the foundation of the United States in the 18th century. As VOA’s Kane Farabaugh reports, local institutions are opening their doors in an effort to capitalize on the convention spotlight to draw visitors, and to offer more than just a history lesson.
    Video

    Video Philadelphia Uses DNC Spotlight to Profile Historic Role in Founding of United States

    The slogan of the Democratic National Convention now underway in Philadelphia is “Let’s Make History Again” which recognizes the role the city played in the foundation of the United States in the 18th century. As VOA’s Kane Farabaugh reports, local institutions are opening their doors in an effort to capitalize on the convention spotlight to draw visitors, and to offer more than just a history lesson.
    Video

    Video Uganda Unveils its First Solar-powered Bus

    A solar-powered bus described by its Ugandan makers as the first in Africa has made its public debut. Kiira Motors' electric bus, Kayoola, displayed recently at a stadium in Uganda's capital. From Kampala, Maurice Magorane filed this report narrated by Salem Solomon.
    Video

    Video Silicon Valley: More Than A Place, It's a Culture

    Silicon Valley is a technology powerhouse and a place that companies such as Google, Facebook and Apple call home. It is a region in northern California that stretches from San Francisco to San Jose. But, more than that, it's known for its startup culture. VOA's Elizabeth Lee went inside one company to find out what it's like to work in a startup.
    Video

    Video Immigrant Delegate Marvels at Democratic Process

    It’s been a bitter and divisive election season – but first time Indian-American delegate Dr. Shashi Gupta headed to the Democratic National Convention with a sense of hope. VOA’s Katherine Gypson followed this immigrant with the love of U.S. politics all the way to Philadelphia.
    Video

    Video A Life of Fighting Back: Hillary Clinton Shatters Glass Ceiling

    Hillary Clinton made history Thursday, overcoming personal and political setbacks to become the first woman to win the presidential nomination of a major U.S. political party. If she wins in November, she will go from “first lady” to U.S. Senator from New York, to Secretary of State, to “Madam President.” Polls show Clinton is both beloved and despised. White House Correspondent Cindy Saine takes a look at the life of the woman both supporters and detractors agree is a fighter for the ages.
    Video

    Video Dutch Entrepreneurs Turn Rainwater Into Beer

    June has been recorded as one of the wettest months in more than a century in many parts of Europe. To a group of entrepreneurs in Amsterdam the rain came as a blessing, as they used the extra water to brew beer. Serginho Roosblad has more to the story.
    Video

    Video First Time Delegate’s First Day Frustrations

    With thousands of people filling the streets of Philadelphia, Pennsylvania for the 2016 Democratic National Convention, VOA’s Kane Farabaugh narrowed in on one delegate as she made her first trip to a national party convention. It was a day that was anything but routine for this United States military veteran.
    Video

    Video Commerce Thrives on US-Mexico Border

    At the Democratic Convention in Philadelphia this week, the party’s presumptive presidential nominee, Hillary Clinton, is expected to attack proposals made by her opponent, Republican presidential nominee Donald Trump, to build a wall along the U.S.-Mexico border. Last Friday, President Barack Obama hosted his Mexican counterpart, President Enrique Peña Nieto, to underscore the good relations between the two countries. VOA’s Greg Flakus reports from Tucson.
    Video

    Video Film Helps Save Ethiopian Children Thought to be Cursed

    'Omo Child' looks at effort of African man to stop killings of ‘mingi’ children
    Video

    Video London’s Financial Crown at Risk as Rivals Eye Brexit Opportunities

    By most measures, London rivals New York as the only true global financial center. But Britain’s vote to leave the European Union – so-called ‘Brexit’ – means the city could lose its right to sell services tariff-free across the bloc, risking its position as Europe’s financial headquarters. Already some banks have said they may shift operations to the mainland. Henry Ridgwell reports from London.
    Video

    Video Recycling Lifeline for Lebanon’s Last Glassblowers

    In a small Lebanese coastal town, one family is preserving a craft that stretches back millennia. The art of glass blowing was developed by Phoenicians in the region, and the Khalifehs say they are the only ones keeping the skill alive in Lebanon. But despite teaming up with an eco-entrepreneur and receiving an unexpected boost from the country’s recent trash crisis the future remains uncertain. John Owens reports from Sarafand.
    Video

    Video Migrants Continue to Risk Lives Crossing US Border from Mexico

    In his speech Thursday before the Republican National Convention, the party’s presidential candidate, Donald Trump, reiterated his proposal to build a wall along the U.S.-Mexico border if elected. Polls show a large percentage of Americans support better control of the nation's southwestern border, but as VOA’s Greg Flakus reports from the border town of Nogales in the Mexican state of Sonora, the situation faced by people trying to cross the border is already daunting.

    Special Report

    Adrift The Invisible African Diaspora