“Forage species such as anchovy, sardine, herring, mackerel and krill often are the main food source for larger predatory fish, marine mammals and seabirds,” said Dr. Tony Smith, a scientist with Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO’s) and lead author of the paper. “They account for more than 30 percent of global fisheries production for use directly as human food and indirectly in livestock feeds, and demand is rising.”

Previous studies have raised concerns about the flow-on effects on seabirds of forage fishing off Peru and South Africa and in the North Sea, and of rising krill catches on whales in the Southern Ocean. “We found forage fishing had large impacts in the five areas studied,” Smith said. “In this study we used three different types of models to examine the broader ecosystem effects when forage fish are harvested at levels that maximize sustainable yields. We found forage fishing had large impacts in the five areas studied - the northern Humboldt, southern Benguela and California currents, North Sea and south-east Australia. These impacts were both positive and negative, and varied across forage species, ecological groups and ecosystems.”

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