POPULATION-DYNAMICS AND PRODUCTION OF THE PLANKTONIC COPEPODS IN A EUTROPHIC INLET OF THE INLAND-SEA OF JAPAN .1. CENTROPAGES-ABDOMINALIS

Population dynamics and production of the calanoid copepod Centropages abdominalis were studied from November 1986 to November 1987 in Fukuy ama Harbor, in the central part of the Inland Sea of Japan. This speci es was present in the plankton during a cold-water period from Novembe r to June (temperature range: 8.9 to 21.1 degrees C), with a peak abun dance (23 600 ind m(-3)) in February. During this period, six generati ons could be detected, and each generation time agreed well with that predicted from food-satiated laboratory experiments, indicating that t he natural population was not food-limited. The population suffered ex tremely high mortality during the period from egg to naupliar stage (N ) II: only 0.02 to 4% of the eggs survived to NII. However, the mortal ity in stages older than NII was almost negligible. The growth rate of C. abdominalis increased exponentially with increasing temperature. I ts biomass and production rate showed marked seasonal variations large ly in parallel with numerical abundance. The estimated production betw een 7 November 1986 and 29 May 1987 was 355 mg C m(-3) or 2.66 g C m(- 2), 95% of which occurred during: February and March. The daily produc tion rate to biomass ratio increased exponentially with temperature fr om 0.18 at 8.9 degrees C to 0.37 at 19 degrees C.