Prior to the copepod collection, seawater was sampled by a 10-l Niskin bottle at 1 m below the surface and 1 m above the sea bottom for the measurement of temperature, salinity, chlorophyll-a
(chl-a) and particulate organic carbon (POC) concentrations. The water from the two depths were pre-filtered through a 100 µm mesh screen to remove net-zooplankton and later combined.