Histological studies on the spent ovaries of aged snow crabs Chionoecetes opilio caught in the Sea of Japan
2010
Kon, T., Wakasa Wan Energy Research Center, Tsuruga, Fukui (Japan) | Ono, M. | Honma, Y.
Aged female snow crabs Chionoecetes opilio, 9 or so years old after their final molt, were collected sporadically from artificial reefs established off the coast of Wakasa Bay, Sea of Japan. In order to clarify the degenerative changes that occur in spent ovaries, the ovaries of these crabs were examined histologically. The ovaries were found to be reduced in both size and volume, with most showing significant oosorption by follicular epithelial cells. Reserve fund eggs and unspawned eggs were rarely detected, with the exception of some in atretic follicles. One to dozens of orange to black nodules scattered over the ovary consisted of masses of degenerative ova in various stages of oolysis. Since nodular formation was recognized in 26% of these aged individuals, it seems very likely that such crabs are unable to spawn healthy eggs.
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