Diurnal variation in vertical distribution of pelagic copepods off Kaikoura, New Zealand

Abstract

The vertical distribution of 55 species of copepods at levels 0–100 m, 100–250 m, 250–500 m, over 21 hours on 20–21 September 1967 at a station 39 km east of Kaikoura (central east coast), New Zealand, is reported, and changes in the night: day biomass ratio at the three depth levels are discussed.Most copepod species counted showed diurnal vertical migratory movements generally similar to those recorded by other workers, but differences between sexes were noted. Modifications to the usual diurnal migratory pattern were observed and are thought to be caused by the animal's physiological state or by changes in the environment.In the surface 250 m, the night: day biomass ratio was >2 but at 250–500 m it was <1. © 1970 Taylor & Francis Ltd.