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.
    Testing Bamboo as Building Materiali
    X
    June 27, 2016 9:06 PM
    For thousands of years various species of bamboo - one of the world's most versatile plants - have been used for diverse purposes ranging from food and medicine to textiles and construction. But its use on a large scale is hampered because it's not manufactured to specific standards but grown in the ground. A University of Pittsburgh professor is on track to changing that. VOA’s George Putic reports.
    Video

    Video Testing Bamboo as Building Material

    For thousands of years various species of bamboo - one of the world's most versatile plants - have been used for diverse purposes ranging from food and medicine to textiles and construction. But its use on a large scale is hampered because it's not manufactured to specific standards but grown in the ground. A University of Pittsburgh professor is on track to changing that. VOA’s George Putic reports.
    Video

    Video Orphanage in Iraqi City Houses Kids Who Lost their Parents to Attacks by IS

    An orphanage in Iraqi Kurdistan has become home to scores of Yazidi children who lost their parents after Islamic State militants took over Sinjar in Iraq’s Nineveh Province in 2014. Iraqi Kurdish forces backed by the U.S. airstrikes have since recaptured Sinjar but the need for the care provided by the orphanage continues. VOA’s Kawa Omar filed this report narrated by Rob Raffaele.
    Video

    Video Re-Opening Old Wounds in a Bullet-Riddled Cultural Landmark

    A cultural landmark before Lebanon’s civil war transformed it into a nest of snipers, Beirut’s ‘Yellow House’ is once again set to play a crucial role in the city.  Built in a neo-Ottoman style in the 1920s, in September it is set to be re-opened as a ‘memory museum’ - its bullet-riddled walls and bunkered positions overlooking the city’s notorious ‘Green Line’ maintained for posterity. John Owens reports from Beirut.
    Video

    Video Brexit Resounds in US Presidential Contest

    Britain’s decision to leave the European Union is resounding in America’s presidential race. As VOA’s Michael Bowman reports, Republican presumptive nominee Donald Trump sees Britain’s move as an affirmation of his campaign’s core messages, while Democrat Hillary Clinton sees the episode as further evidence that Trump is unfit to be president.
    Video

    Video New York Pride March A Celebration of Life, Mourning of Loss

    At this year’s march in New York marking the end of pride week, a record-breaking crowd of LGBT activists and allies marched down Manhattan's Fifth Avenue, in what will be long remembered as a powerful display of solidarity and remembrance for the 49 victims killed two weeks ago in an Orlando gay nightclub.
    Video

    Video NASA Juno Spacecraft, Nearing Jupiter, to Shed Light on Gas Giant

    After a five-year journey, the spacecraft Juno is nearing its destination, the giant planet Jupiter, where it will enter orbit and start sending data back July 4th. As Mike O'Sullivan reports from Pasadena, California, the craft will pierce the veil of Jupiter's dense cloud cover to reveal its mysteries.
    Video

    Video Orlando Shooting Changes Debate on Gun Control

    It’s been nearly two weeks since the largest mass shooting ever in the United States. Despite public calls for tighter gun control laws, Congress is at an impasse. Democratic lawmakers resorted to a 1960s civil rights tactic to portray their frustration. VOA’s Carolyn Presutti explains how the Orlando, Florida shooting is changing the debate.
    Video

    Video Tunisian Fishing Town Searches for Jobs, Local Development Solutions

    As the European Union tries to come to grips with its migrant crisis, some newcomers are leaving voluntarily. But those returning to their home countries face an uncertain future.  Five years after Tunisia's revolution, the tiny North African country is struggling with unrest, soaring unemployment and plummeting growth. From the southern Tunisian fishing town of Zarzis, Lisa Bryant takes a look for VOA at a search for local solutions.
    Video

    Video 'American Troops' in Russia Despite Tensions

    Historic battle re-enactment is a niche hobby with a fair number of adherents in Russia where past military victories are played-up by the Kremlin as a show of national strength. But, one group of World War II re-enactors in Moscow has the rare distinction of choosing to play western ally troops. VOA's Daniel Schearf explains.
    Video

    Video Muslim American Mayor Calls for Tolerance

    Syrian-born Mohamed Khairullah describes himself as "an American mayor who happens to be Muslim." As the three-term mayor of Prospect Park, New Jersey, he believes his town of 6,000 is an example of how ethnicity and religious beliefs should not determine a community's leadership. Ramon Taylor has this report from Prospect Park.
    Video

    Video Internal Rifts Over Syria Policy Could Be Headache for Next US President

    With the Obama administration showing little outward enthusiasm for adopting a more robust Syria policy, there is a strong likelihood that the internal discontent expressed by State Department employees will roll over to the next administration. VOA State Department correspondent Pam Dockins reports.
    Video

    Video Senegal to Park Colorful ‘Cars Rapide’ Permanently

    Brightly painted cars rapide are a hallmark of Dakar, offering residents a cheap way to get around the capital city since 1976. But the privately owned minibuses are scheduled to be parked for good in late 2018, as Ricci Shryock reports for VOA.

    Special Report

    Adrift The Invisible African Diaspora