Albacore are top carnivores in the ocean ecosystem and opportunistically prey on schooling stocks, such as sardine, anchovy, and squid. Albacore eat enormous amounts of food to fuel their high metabolism, at times consuming as much as 25% of their own weight every day. Albacore are preyed upon by man, as well as the larger species of billfish, tuna, and sharks. Given albacore are routinely harvested by both surface-fishing gear (e.g., troll and pole-and-line) and subsurface-fishing gear (e.g., longline), it is presumed they feed in at least the upper 500 m of the ocean. Albacore feed primarily during the daylight hours; however, some studies have indicated that they will also feed at night, although limited stomach contents suggested that the rate was much reduced–presumably, due to less successful foraging, given they are thought to be essentially sight-feeders.