Egg Production of a Brackish-water Calanoid Copepod Sinocalanus tenellus in Relation to Food Abundance and Temperature
The egg production rates of a brackish-water calanoid copepod Sinocalanus tenellus were investigated under controlled laboratory conditions. Females laid eggs in discrete egg-masses rather than egg-sacs. In a few minutes after laying, these eggs were separated and shed into the water. Histological examination revealed that this egg-laying pattern was due to the synchronous maturation of a batch of oocytes in the oviducts. Food supply and temperature influenced the spawning interval (i.e. the rate of maturation of oocytes) much more than the clutch size (i.e. the number of eggs in a spawning event). At high food concentrations, the egg production rate became maximal around 20°C at 60 eggs female^<-1> d^<-1> or 0.37 d^<-1> in terms of carbon weight-specific rate. S. tenellus was capable of producing more than 2531 eggs during 70 days after molting to adult. Frequent matings (i.e. after every ca. 100 eggs produced) were required to enable the production of fertilized eggs throughout the female's reproductive period.
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Copyright (c) 1986 The Plankton Society of Japan
Graduate School of Biosphere Science