Progress in Oceanography 43 (1999) 365–397 Epipelagic nekton of the North Pacific Subarctic and Transition Zones Richard Brodeur a,* , Skip McKinnell b , Kazuya Nagasawa c , William Pearcy d , Vladimir Radchenko e , Shogo Takagi f a Alaska Fisheries Science Center, NMFS, Seattle, WA 98115, USA b Pacific Biological Station, DFO, Nanaimo, BC, V9R 5K6, Canada c National Research Institute of Far Seas Fisheries, Shimizu, 424 Shizuoka, Japan d College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA e Pacific Scientific Research Fisheries Centre, TINRO-Centre, Vladivostok 690600, Russia f Faculty of Fisheries, Hokkaido University, Hakodate, Hokkaido 041, Japan Abstract During the 1980s and 1990s, scientific research cruises and commercial gillnet operations with scientific observers aboard were conducted throughout much of the Subarctic and Tran- sition Zones of the North Pacific Ocean. These studies produced one of the most extensive databases ever collected on the relative species composition and trophic structure of epipelagic nekton of the Subarctic and Transition Zones in the North Pacific Ocean. Data from Japanese high-seas gillnet research surveys (1981–1991) were examined using multivariate analytical techniques to analyse community structure of nektonic cephalopods, elasmobranchs, and teleosts in the North Pacific Subarctic and Transition Zones during the summer months, emphasizing differences between the eastern and western Subarctic Gyres. Species diversity generally increased going from west to east, which was apparently associated with the greater range of temperatures in the east. Discriminant analysis was able to correctly classify about half the catch locations into their respective regions. Catches from multinational drift gillnet commercial fisheries operations in 1990–1991 mainly in the Transition Zone were also exam- ined. Classification techniques were employed to determine species associations and multivari- ate analyses were used to examine relationships of these assemblages to environmental data. We found that some species are often captured in the same gillnet sets and form species associations that are distinct in ordination space, but these associations are loose and may vary appreciably from year to year. We review recent studies on the feeding habits and daily ration of the dominant species and construct food webs for the eastern and western Subarctic and * Corresponding author. Present address: Northwest Fisheries Science Center, NMFS, Newport, OR 97365 USA. 0079-6611/99/$ - see front matter  1999 Elsevier Science Ltd. All rights reserved. PII:S0079-6611(99)00013-0