Scientists are finding evidence of widespread malnutrition in commercial and recreational fish, marine mammals, and seabirds because of the global depletion of the small fish they need to survive, according to Oceana's new report, "Hungry Oceans: What Happens When the Prey is Gone?" These "prey fish" underpin marine food webs and are being steadily exhausted by heavy fishing, increasing demand for aquaculture feed, and climate change.
"We have caught all the big fish and now we are going after their food," said Margot Stiles, marine scientist at Oceana. "Until recently it has been widely believed that prey fish are impossible to overexploit because their populations grow so quickly. We are now proving that untrue as the demands of commercial fisheries and aquaculture outpace the ocean's ability to provide food for us and itself."
Hungry Oceans finds that 7 of the top 10 fisheries in the world target prey fish. These fisheries have emerged as populations of bigger fish have become overexploited and depleted. The report concludes that the impacts of fishing activity over the past decades has been so great that the nearly all prey fisheries now cannot withstand increased fishing pressure. Hungry Oceans also finds that 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.
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. Very few marine fish populations remain with the potential to sustain production increases, and more have now reached their limit than ever before.