Latitudinal distribution and environmental relation of zooplankton in the northwest Pacific Ocean

Abstract

We investigated in order to the latitudinal variations in zooplankton abundance and their related environmental variations of four distinctive regions, Warm pool area(WP), Philippine EEZ, Japan EEZ, East China Sea (ECS), located in the northwestern Pacific, between 30 Nov. and Oct. 16 2007. Temperature, salinity, chlorophyll-a (chl-a), protozoa were sampled within the depth from the surface to 200 m depth. Zooplankton samples were obliquely collected from near 200-300m depth to the surface. The distribution of biological variations such as chl-a, protozoa biomass was highest in ECS and lowest in WP. Also, distribution of zooplankton biomass and abundance was similar to that of biological variations. Zooplankton biomass showed significantly positive relationship with temperature and total chl-a (r2=0.90, p<0.001). In ANOVA analysis for examining the relationships among zooplankton abundance, stations, environmental variations, the study area was distinguished WP and Philippine EEZ from Japan EEZ and ECS (continental slope and shelf area). Our result suggest that zooplankton community distributed in the WP and Philippine EEZ directly affecting Kuroshio current might be significant influenced by physical factor (temperature) but Japan EEZ and ECS was characterized by biological factor (chl-a).