Reproductive patterns of harpacticoid copepods on intertidal macroalgae ( Ascophyllum nodosum and Fucus vesiculosus) in Nova Scotia, Canada.

Harpacticoid copepods generally showed marked seasonal variation in abundance on a moderately exposed rocky shore. In Nitocra typica, Mesochra spp, Harpacticus sp and Heterolaophonte spp the sex ratio was unbiased, or biased towards males, at peak population densities in summer and fall, but became biased towards females as density decreased towards winter. In Thalestris purpurea, Parastenhelia spinosa and Amphiascopsis sp there was no consistent trend in sex ratio. Most species have a protracted period of reproductive activity between spring and fall. Harpacticus sp, Heterolaophonte discophora and T. purpurea, absent from macroalgae during winter, reappeared with ovigerous females and copepodities in spring. Tisbe spp showed no seasonal flucturation in abundance or sex ratio: ovigerous females and copepodites occurred throughout the year, suggesting continuous reproduction. Reproductive patterns of harpacticoids on intertidal macroalgae may be related to seasonal variation in temperature and food supply. -from Authors