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

• Published in: Canadian Journal of Zoology
• Main Authors: Johnson, S. C., Scheibling, R. E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1987
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Canada; Copepods; Harpacticus
• Online Access: http://dx.doi.org/10.1139/z87-019; http://www.nrcresearchpress.com/doi/pdf/10.1139/z87-019

Harpacticoid copepods generally showed marked seasonal variation in abundance on intertidal macroalgae (Ascophyllum nodosum, Fucus vesiculosus) on a moderately exposed rocky shore. In some species (Nitocra typica, Mesochra spp., Harpacticus sp., 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 other species (Thalestris purpurea, Parastenhelia spinosa, Amphiascopsis sp.) there was no consistent trend in sex ratio. Most species have a protracted period of reproductive activity between spring and fall, as indicated by the occurrence of ovigerous females and copepodites. Some species (Harpacticus sp., Heterolaophonte discophora, Thalestris purpurea) that were absent from macroalgae during winter reappeared with ovigerous females and copepodites in the spring. Tisbe spp. showed no seasonal fluctuation in abundance or sex ratio: ovigerous females and copepodites occurred throughout the year, suggesting continuous reproduction. Reproductive patterns of harpacticoid species on intertidal macroalgae may be related to seasonal variation in temperature and food supply.