Interactions between fish species on seamount coral habitat

Abstract

The behaviour of the scorpionfish Helicolenus dactylopterus and Pontinus kuhlii towards the zooplanktivores Anthias anthias and Callanthias ruber are described from rare in situ remote-operated vehicle (ROV) observations. The events were recorded by ROV SP on gorgonian habitats of Dentomuricea meteor and Viminella flagellum, at the summit of Condor seamount (212–223 m; Azores, Northeast Atlantic). Behaviour in both species included approaching the zooplanktivores from a sitting position, orientating the snout in front of the object and swimming in a straight line. After an initial slow displacement, it follows an adduction of dorsal, pectoral and anal fins and an increase in speed, occasionally accompanied of a burst swim. H. dactylopterus can reach up to 0.8 m above the seafloor, departing from more than 1.5m distance; P. kuhlii was observed only on one occasion, chasing A. anthias from 0.64-m distance, with average swimming velocities of 1–2 m/s. The possibility of predatory or agonistic behaviour is discussed, with more evidence being gathered towards the former, representing a possible linkage between the pelagic and the benthic realm.