Relationship between mass
mortality of megalops and morphogenesis of zoeas in the seed production of
swimming crab Portunus trituberculatus (Brachyura: Portunidae)
D. Arai, K. Hamasaki, K. Maruyama, Y. Obata, S.-I.
Tsumura, M. Takano-2004
Nippon Suisan Gakkaishi, 70(4): 567-572
Abstract:
We described the relationship between the mass
mortality of megalops and the morphogenesis of zoeas in the seed production
of the swimming crab Portunus trituberculatus. The survival rate of
larvae from the last (fourth) zoeal stage to the first crab stage was lower
than that from the first to fourth zoeal stage. Survival rate tended to
decrease with increasing frequency of abnormal molting during the
metamorphosis to megalops. The relationship between the frequency of
abnormal molting and the relative chela length to carapace length in the
fourth zoeal stage showed a significant positive correlation. Thus, it was
revealed that the morphologically advanced fourth stage zoeas were unable to
undergo normal metamorphosis to megalops and larval mass mortality occurred.
(Tamano Station, National Center for Stock
Enhancement, Fisheries Research Agency, Tamano, Okayama 706-0002, Japan)