Foraging and associated behavior by Octopus cyanea Gray, 1849 on a coral atoll, French Polynesia

Abstract

Individual Octopus cyanea Gray, 1849 were observed continuously while foraging over a 6 day period during daylight hours. Foraging usually occurred once early in the morning and once late in the afternoon, and successive forages did not duplicate the same routes. On average, single forages ( n = 16) covered 81 m (max. 129 m), lasted 118 min (max. 6 h), and often included up to five types of substrata. Octopuses spent about 28% of daylight hours foraging, usually in a saltatory (stop and go) search strategy. Small fishes (five species) often followed foraging octopuses. Foraging was tactile and speculative: octopuses either pounced on a likely object with the web spread, or groped deeply into crevices with the long arms, according to substratum. No octopus was observed to make direct, visually guided attacks on prey. These field observations suggest that their keen eyesight is used for determining the foraging path, scanning for predators, matching the substrata for crypsis, and finding their way back to their dens.