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The production rate and population dynamics of the egg-carrying calanoid copepod Pseudodiaptomus marinus from the Fukuyama Harbor of Japan were studied. Results show that the egg-carrying calanoids have a low mortality rate during early life stages in comparison with the high mortality rate of free-spawning calanoids during the same period. Furthermore, temperature affects the egg production rate causing a low population density in midwinter and an increased production in May.

The population dynamics and production rate of calanoid copepod Paraclanus sp. in Fukuyama Harbor, a eutrophic inlet in the Inland Sea of Japan were studied. The study indicated that Paraclanus sp. was present in the zooplankton population throughout the year. Egg production rates in the natural population was constant. Mortality between egg and NIII was high and fluctuating due to predation and the sedimentation of eggs from the water column.

Population dynamics and production of the calanoid copepod Acartia omorii Bradford were investigated from Nov 1986 to Nov 1987 in Fukuyama Harbor, a eutrophic inlet of the Inland Sea of Japan. The population suffered extremely high mortality during the early life stages. However, the mortality from the naupliar Stage II to copepodite Stage V was negligible, suggesting low predation pressure by large carnivores. The biomass of A. omorii indicated substantial seasonal variations in parallel with numerical abundance.

The planktonic copepods, Centropages abdominalis, are present in the Fukuyama Harbor, Inland Sea, Japan, during the cold-water period from Nov to Jun with maximum population size in Feb. The copepods population suffers high mortality during the egg to naupliar stage II. The mortality in the later developmental stages is negligible. The rate of growth of the copepods increases as the temperature increases. The growth rate and the biomass show seasonal changes which are associated with the population size.

The diel vertical migration and distribution of all the developmental stages of the copepod Calanus sinicus during a season of weak thermal stratification in the inland Sea of Japan was investigated. The results showed strong diel vertical migration depending on the the stage of development. Eggs and pre-feeding nauplii had similar distributions, while the first feeding nauplius showed pronounced upward migration. Late nauplii and early copepodites were more concentrated in the upper layers with higher phytoplankton density, while adults were dispersed in the water column.