Morphometrics and Length-Weight Relationship in the Blue Swimmer Crab, Portunus pelagicus (Linnaeus, 1758)
(Decapoda, Brachyura) from the Mandapam Coast, India
In this study, the interrelationships between various morphometric characters, viz., carapace
width and length and chelar propodus length and height in males, as well as carapace width and
length and abdominal width and length in females, were estimated using a total of 980 crabs,
Portunus pelagicus. The carapace width/length — weight relationship was studied in both sexes
on a total of 1188 crabs using the allometric growth equation of Von Bertalanffy. The allometric
relationships between the characters of this set suggest that most relationships are positive and
highly significant. The ‘b’ values for carapace width-weight in males and females were 3.607 and
3.293, respectively, and for carapace length-weight they were 3.049 and 2.774, respectively. The
results show a significant deviation from an isometric growth pattern. An analysis of covariance
indicates that there is a significant difference between sexes with respect to the carapace widthweight
relationshi
