The role and status of Nautilus in its natural habitat: evidence from deep-water remote camera photosequences

Abstract

Bottom site remote camera photosequences at depths of 73–538 m on forereef slopes in Palau show that Nautilus belauensis is a highly mobile, chemosensitive, epibenthic scavenger and opportunistic predator. The overall depth range of this species is ca. 70–500 m, but photosequences indicate a preferred range of 150–300 m. Nautilus is active both nocturnally and diurnally, locating bait sites within 1–2 h. Associated macrofauna includes caridean shrimps, crabs, and eels; teleosts are rare below 100 m, but sharks are recorded in most photosequences below 250 m. Summarily, Nautilus exhibits a combination of characters that typify deep-sea strategy, including reproductive tactics, growth rate, and population dynamics. This and other evidence suggest that fossil Nautilidae may have been deep-water forms, in contrast to the typically shallower water ammonoids, and that Nautilus is a normal component of the deep forereef rather than a late Cretaceous refugee from shallow water.