Large fish go hungry as a result of overfishing

Posted: March 5, 2009 in environment

sand-tiger-shark

Schooling prey fish surround a Sand Tiger Shark. [Credit: Gordon Stroupe]

Today Oceana released a new report, “Hungry Oceans: What Happens When the Prey is Gone?” that shows how overfishing, aquaculture feed and climate change are causing widespread malnutrition in predator fish, marine mammals and birds. As Oceana marine scientist Margot Stiles put it, “We have caught all the big fish and now we are going after their food.”

As populations of bigger fish have become overexploited and depleted, fisheries have emerged targeting prey fish — 7 of the top 10 fisheries in the world, in fact. In addition, aquaculture is increasingly the driver behind overfishing of prey fish, as salmon, tuna and other carnivorous farmed fish become the fastest growing seafood products in the world. Changing ocean temperatures and currents caused by climate change also make prey fish populations more vulnerable.

So who’s going hungry? To begin with, ocean predators such as whales, dolphins, seals, sea lions, and birds, who depend on squid, krill, and small fish to survive. In addition, many valuable commercial and recreational fisheries, specifically bluefin tuna, striped bass, Pacific salmon, and Pacific halibut are key species that depend on prey fish. Mediterranean bottlenose dolphins, for example, have declined significantly, in part because of overfishing of sardines and anchovy. Scientists working in the eastern Ionian Sea found 40 percent of bottlenose dolphins visibly emaciated due to starvation and other causes. The solution? More responsible management of fisheries.

The report ends with a proposed series of measures including a moratorium on new fisheries targeting prey species, conservative catch limits for existing fisheries, first priority for the needs of ocean predators, and stopping fishing for prey in predator breeding hotspots. “Hungry Oceans” coincides with the release today of the biennial State of the World Fisheries and Aquaculture report by the U.N. Food and Agriculture Organization (FAO). The FAO concludes that 80% of all marine fish stocks are currently fully exploited, overexploited, depleted, or recovering from depletion; including stocks of the 7 largest prey fisheries.

[Thanks to Oceana]

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