Vertical distribution of Pleuromamma (Copepoda: Metridinidae) across the eastern North Pacific Ocean

Vertical distributions of six species of Pleuromamma at ten stations across the eastern North Pacific Ocean from Honolulu to San Diego were determined from oblique Longhurst-Hardy Plankton Recorder tows to 650 m (350–450 m in the California Current). Vertical resolution was 20 m below 200 m and 5–10 m above. There was considerable overlap in surface layer distributions at night among all co-occurring species; daytime distributions showed less overlap. All species generally occurred deeper both day and night as distance offshore increased. The proportion of a species' population that remained at daytime depths during the night decreased with distance offshore. Warm water species penetrated into the California Current and nearshore region to a much greater extent than cool water species entered central gyre waters.