National Geographic : 2010 Oct
LEVEL LEVEL 4 3 The Ocean Food Chain INTERMEDIATE PREDATORS These species are vital for keeping lower-level fish populations in check. ATLANTIC HERRING Important prey for seabirds, ocean mammals, and other fish, the Atlantic herring was overfished in the 1960s but is now recovering. ALASKA POLLOCK Although its biomass has declined in recent years, this species (often sold as fish sticks) remains the largest U.S. fishery by volume. JAPANESE FLYING SQUID Preyed upon by albatrosses and sperm whales, the Japa- nese flying squid lives only a year or so but can replenish its population quickly. ATLANTIC SALMON Most Atlantic salmon sold in the U.S. come from aqua- culture operations, where they are fed fish meal, adding to the pressures on wild fish. ORANGE ROUGHY The orange roughy fishery in the Southern Hemisphere was heavily exploited in the 1980s. The largest of these deep-sea fish live a century or more. ATLANTIC BLUEFIN TUNA Because overfishing has cut the population of this fish to a fraction of its original abundance, conservationists urge a fishing moratorium. TOP PREDATORS Slow to reproduce, these fish are among the most energy demanding in the sea.