NORTHERN FUR SEAL BIOLOGY
Northern fur seal diet is well known from stomach content and fecal material analysis throughout their range in the Bering Sea and North Pacific Ocean. Fur seals eat a wide variety of small schooling fishes and squids. Diet composition varies between the six major breeding islands and changes during their annual migration. Sixty-three species of fishes and squids have been identified throughout their range. In the Bering Sea, fur seals primarily consume walleye pollock, squids, salmon, Pacific sandlance, northern smoothtongue and Pacific herring. Between Alaska and California the primary prey species are northern anchovy, Pacific herring, squids, capelin, Pacific sandlance, Pacific whiting, salmon, Pacific saury and rockfishes.
Northern fur seals are carnivores that feed primarily at night. From dusk until dawn, fishes and squids are near the ocean’s surface where they are easily captured by fur seals. During the breeding season, fur seals can travel distances ranging from 350 – 1000 km at sea, and dive to depths reaching 200 meters to search for food. Three types of diving patterns are exhibited by fur seals: shallow, deep and mixed diving. Over the continental shelf (<200 m deep) deep divers feed throughout the day and night on fish found throughout the water column. In oceanic waters off the continental shelf (3000 m deep) shallow nighttime divers feed on fish and squids found in the upper 50 m of the water column. Mixed divers tend to feed along the continental shelf edge and display both diving patterns. Fur seals don’t chew their food; they swallow it in large chunks.
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