Growth,reproduction & population structure of the freshwater crabSinopotamon yangtsekiense bott, 1967, from Zhejiang,China |
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| Authors: | Chen Tao Lai Wei Du Nan-shan |
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| Institution: | (1) Department of Biology, Anhui University, 230039 Anhui;(2) Department of Biology, East China Normal University, 200062 Shanghai |
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| Abstract: | Monthly investigations were mae on the population of Chinese freshwater crab,Sinopotamon yangtsekiense Bott, 1967 from April, 1984 to March, 1985. The data on 4413 specimens show that the growth was affected mainly by temperature.
During the April to November growth period, the crabs' major development occurred from June through October. One year was
required for a fine white oocyte to develop into a mature egg. The reproduction period was June–October. Females bearing eggs
were taken from June–August, and crabs with young were found from July–October. The females reproduced once a year but could
for more than one year. The number of eggs carried by a female varied greatly according to the size of the crab, ranging from
30 to 100 eggs. New-born crabs become mature after 1–2 years. The sex ratio was approximately 1∶1 in the overall population.
However, the larger crabs are predominantly male. The age distribution ofS. yangtsekinese was estimated from size frequency histograms. There were more adult crabs (over 70%) from June to October and more immature
crabs (over 50%) from November to May. |
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| Keywords: | growth curve vitellogenesis population S yangtsekiense sex ratio |
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