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Chinese Bioscience 42(1): 41-56 (1999)
¡@The Timing of Larval Release by Coastal Crabs
Hsi-Te Shih
¡@ Periodic reproductive synchrony is a common phenomenon occurred in the coastal benthic crab species, especial the timing of larval release. When the night high tide of spring tide, most species of ovigerous female crabs release their larvae near the water edge synchronously. Because there is obvious relationship between the timing of larval release and environmental cycles, the mechanism of larval release can be investigated by endogenous rhythms of marine animals. The endogenous rhythms include tidal, lunadian, daily, semilunar (biweekly), monthly and annual rhythms. The hypothesis of the avoidance of predation of planktivorous fishes is supported by comparison of the timing of larval release of different crab species and the morphological characters and coloration of the larvae. Alternative hypotheses suggested included avoidance of predation by invertebrates, avoidance of physiological stress, avoidance of UV, avoidance of larval stranding, settlement-timing, energy cost of female, and promotion of larval dispersal.
Keywords: Reproductive synchrony, Rhythm, Entraining agent, High slack tides.
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