چکیده
A study of the size composition and growth pattern of two economically important portunid crabs Callinectes
amnicola, and Portunus validus from Lagos Coast was conducted from April to September, 2016 using standard
morphological techniques. A total of 715 crabs obtained from fishing trawlers were examined. The carapace
length for C. amnicola ranged from 2.8 cm to 7.4 cm (Caparace width 4.0 to 14.9cm) and total weight from 11.4
g to 232.0 g, while the carapace length of P. validus ranged between 4.1cm and 10.9cm (Carapace width 8.0cm to 18.0cm) and weight 70.0g to 616.0g. Both portunid crabs exhibited negative allometric growth as shown by the mean exponents ‘b’=2.271 for C. amnicola and ‘b’=2.676 for P. validus. There was high correlation (r almost =1) between carapace width and body weight of the crabs with a coefficient (r) ranging between 0.931 and 0.951 for C. amnicola and between 0.887 and 0.921 for P. validus. Condition factor ranged between 4.27 and 5.58 (mean 5.23) in C. amnicola and between 4.56 and 22.82 (mean 9.56) in P. validus. The condition factor decreased with increase in size of P. validus but slightly increased with increase in size of C. amnicola. The fairly higher biometric dimensions showed by both portunid species implies that the station is environmentally dynamic.
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