Diversity of crabs in Pulicat coast

Twelve species of brackish water brachyuran were identified in major landing centers of Pulicat Lake They are Scylla serrata, Scylla tranqueberica, Matuta lunaris, Thalamita crenta, Chayribdis natator, Chayribdis feriatus, Portunas pelagicus, Portunas sanguinolentus, Uca annuplies, uca triangularis, Cardisoma carnifex, Diogenes avarus. There are two Uca species were identified in Pulicat. They are Uca annulipes and Uca triangularis. Density of fiddler crabs varied from 6 to 114 no /sq. meter. Measurement of burrow was observed with the presence of hoods, dimension, angle of decent of holes and burrow depth were noticed. Claw wavings were observed.  There are 4 types  of claw waving were  noticed such as  lateral circular waving, lateral flick waving, Rapid vertical waving, circular waving. Colour variation of the uca were noticed .  The colour  variation in the carapace of uca occurs according to the  increase in temperature. Colour of the uca increases, when the temperature increases.Variation of temperature,  Salinity and pH from  28.9 to 32.8 ^OC,  14  to 26 ppt  and 6.6 to 7.5