Aggregating behaviour, social interactions and possible spawning in the deep-water fish Coryphaenoides rupestris.

A dense aggregation of the roundnose grenadier Coryphaenoides rupestris was observed with a towed camera at a depth of 1500 m in the Rockall Trough during September. The density of fish was 100 times greater than other sites. Within the aggregation the fish showed directional alignment, rapid swimming actions, mid-water swimming and social interactions similar to those associated with spawning in other Gadiformes.