Reproductive rate of a marine planktonic copepodLabidocera euchaet a Giesbrecht in Xiamen Harbor

Abstract

Reproductive rate of a marine planktonic copepodLabidocera euchaeta Giesbrecht in Xiamen Harbor bor was studied during the period from April 1986 to August 1987. Results showed that rate of egg production (F, eggs/(♀, d)) was positively correlated with temperature (T,oC) and body weight of spawning female (Wc, μgC) as:F=0.0637 (T−7)0.7445Wc. Each month a maximum rate of egg production occurred at one of the five experimental temperatures (10°, 15°, 25°, and 30°C) near the monthly mean field temperature. The available food density (P, μgC/ml) had significant effect on specific rate of egg production (Fc, %C ♀/d) as:Fc=0.1732 (P-0.0179)/P. The gross efficiency of egg production of ca 62% in carbon was independent of food density snd ingestion rate. Observations on in situ egg production and hatching rate demonstrated that this species reproduces continuously all the year round, with summer as its high reproductive season and winter a low one. Ten generations a year is also suggested based on the number of the peaks of average population egg production rate. This agreed well with the result obtained from the generation-time equations. Egg-laying pattern was also observed and discussed.