Growth and Breeding of the Swimming Pea Crab Tritodynamia horvathi Reared in the Laboratory

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Larvae of the swimming pea crab Tritodynamia horvathi hatched in the laboratory were reared to adult, and were bred successfully. Zoeal larvae were obtained from ovigerous females collected at Yatsushiro Sound, and they were reared on rotifers, Artemia nauplii and artificial diet. Zoeae hatched in April passed through five zoeal stages during 15-22 days, and the duration of the megalopal stage was 5-11 days. First stage crabs reached the fifth crab stage within two months. Ovigerous females first appeared from September 14, 6 days after the first copulation was observed. However, the percentage of ovigerous females over this period was less than 7%. Copulation and ovigerous females were not detected during November to January. After February 8, copulation resumed and ovigerous females appeared again. The percentage of ovigerous females in the latter breeding season reached 78%. When the crabs were swimming in the aquarium, they were constantly moving their maxillipeds in a regular pattern, and fed on Artemia nauplii or powder of pellets. This suggests that the swimming behavior of T. horvathi is not apeculiar behavior restricted to mating as the copulatory swimming recorded in some other pinnotherids, but a behavior for feeding.