Forage fish have been described as "fuel for the food web" because they are the food that sustains larger predators higher up in the ocean food chain. Their schooling behavior and superabundance make them ideal food sources for large populations of top predator fish such as tuna, striped bass, cod, flounder, salmon, or swordfish, as well as whales, dolphins, porpoises, seals, sea lions, and seabirds. Without forage fish the ocean food web would collapse and no longer support large, diverse assemblages of top predator species.

Prior to the 1950s, forage fish represented a relatively small share of the global marine fisheries catch every year - less than 8% by one estimate. Since the 1950s, new fishing technologies and factory fishing vessels have enabled humans to remove ever-growing quantities of forage fish from the oceans. In 2002, forage fish accounted for 36 percent of the global marine fish landings, totaling more than 30 million metric tons (66 billion pounds). Most of these fish were not intended for human consumption but processed directly into fishmeal and fish oil to be used in poultry, livestock, and aquaculture feeds, and the boom in global aquaculture is putting increased pressure on forage fisheries to expand in order to supply more feedstock for farmed fish. Without effective measures to protect forage fish and limit their exploitation, today's high-tech industrial fisheries will continue to plunder the ocean food web and diminish the food supply of many dependent marine predators, with lasting consequences.