False Boarfish Neocyttus helgae in the Western North Atlantic

Abstract

Direct underwater observations at seamounts across the western North Atlantic basin revealed the presence of the false boarfish, Neocyttus helgae (Oreosomatidae), at depths of 915 to 1829 m. These observations extend the known range of this species across the North Atlantic basin and support the hypothesis that seamounts are stepping stones for dispersal. Fishes were associated with basalt habitats featuring corals and sponges (both nearly horizontal basalt sheets and steep cliffs) as well as depressions in sheets of basalt. These features provided refuge from flow and predators as well as immediate access to zooplankton and pelagic prey delivered by rapid currents. Encounters with fishes were primarily as single individuals or pairs. Territorial behaviors, such as raised dorsal spine and lateral display, occurred when submersible vehicles approached fish, suggesting that territorial defense is a common behavioral attribute.