Growth pattern and specificity of attachment of lagoon crab (Callinectes amnicola) fouled with barnacles (Chelonibia patula) from Lagos Lagoon, Southwest Nigeria

The growth pattern and condition factor (K) of 810 Lagoon crabs (Callinectes amnicola) fouled with Barnacles (Chelonibia patula), collected from Makoko Jetty, off Lagos Lagoon between April-September 2011 were studied. The carapace length f C. amnicola examined ranged from 3.8cm-8.6cm while the carapare width ranged from 9.5cm-15.4cm. The total weight ranged from 53.1g to 165.0g, indicating that increase in length correspond to increase in weight, thereby suggested that C. amnicola from Lagos Lagoon exhibited a negative allometric growth. The correlated coefficient 'r' for the crabs was 0.68, showing a low correlation between carapace length weight in the lagoon crabs fouled with barnacles. The condition factor (K) values of C. amnicola fouled with barnacles ranged from 3.2-9.7 with a mean value of 5.4. The highest K-value was recorded for the size group 3.5-4.4. The value decreased with increased length of C. ammcola. The sex ratio (1:80) indicated that there were more females (98.8%) than males (1.2%), 12 (1.5%) of the 810 lagoon crabs examined were heavily fouled with barnacles distributed all over the points of attachment with the cora having the most attachment (91.6 6%). Average diameter of the barnacles attached to the crabs ranged from 0.23cm to 1.85cm. The distribution shows that large-sized crabs had much banacles attached to them than small-sized crabs, with greater barnacles found in the females than in the males