Pelagic amphipod assemblage associated with subarctic water off the West Coast of the Baja California peninsula

摘要: Abstract The California Current system is a large marine ecosystem with transition gradients between subarctic and tropical biomes containing diverse habitats. Biogeographic species groups must be carefully analyzed in order to detect tendencies shifting the toward more temperate or state. Species composition of hyperiid amphipods was July 2002 for evidence water intrusion signals El Nino event developing equatorial Pacific. Multivariate analysis showed dominance “transition zone” typical Current. main extended distribution Themisto pacifica, which reached as far south 27°N, particularly high abundances at 30–32°N. took place despite that an progress. zonal advection due intersected equatorward flow probably produced cyclonic eddy off Baja California. This maintained limited influence few offshore stations near its southern boundary. environmental variables influencing amphipod assemblage structure were temperature abundance salps. T. cool affinity, sensitive temperature, whereas subtropical species, such Vibilia armata, strongly correlated availability