Aspects of the biology of blue crab Callinectes amnicola (DE Rocheburen, 1883) in Lagos lagoon, Nigeria

Document Type: Primary Research paper

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Abstract

The length-weight relationship, condition factor and sex ratio of blue crab Callinectes amnicola from Lagos Lagoon, Lagos State, Nigeria were studied for a period of one year. Each crab was sorted into species, sex and the required metric measurements were taken. The carapace width and length were measured to the nearest millimetre (mm) while weight was measured to the nearest grams (g). The length-weight relationships of all samples collected were determined for the various sexes. The exponent ‘b’ values for all the sexes from the 3 stations significantly different (p<0.001) ranged from 2.170-2.928. The growth generally exhibited negatively allometry in all the sexes throughout the 3 stations. The condition factor (k) values were significantly different (p<0.001) ranged from 5.73-7.53.The “k” values of male crabs were higher than female crabs across the 3 stations. The sex ratios differ significantly from the expected 1:1 ratio; the female blue crabs were more abundance than males in all the stations, which suggests the stations to be breeding ground for crabs. 

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