Production of Acartia steueri (Copepoda : Calanoida) in Ilkwang Bay, southeastern coast of Korea

Abstract

Production of the marine calanoid copepod Acartia steueri was measured from 2 October 1991 to 8 October 1992 at a station in Ilkwang Bay, on the southeastern coast of Korea. Phytoplankton standing stock ranged over 1.0 to 9.3 mg chl.a m(-3), and annual primary productivity (by the C-14 method) at three stations was estimated at 200 gC m(-2) yr(-1). Acartia steueri (nauplii + copepodids + adults) were present in the plankton throughout the year, with seasonal variation in abundance. Biomass of A. steueri, excluding the NI stage, was 0.01-4.55 mgC m(-3) (mean: 0.68 MgC m(-3)) with peaks in November, February, May and July-early August, and relatively low biomass in September-January. Instantaneous growth rates of the nauplius stages were higher than the copepodid stages. Annual production of A. steueri was 25.1 mgC m(-3) yr(-1) (or 166 mgC m(-2) yr(-1)), showing peaks in November, May and July-August with a small peak in February, and low production in December-April and September-October. There were no significant relationships between the daily production rate of A. steueri and temperature or chlorophyll a concentration, indicating that unknown other factors might be related to the variation of the production rate.