Morphometric Analysis of the Red Frog Crab “Curacha” Ranina ranina from Balut Island, Sarangani, Davao Occidental

Abstract

The morphometric character relationships of females and males of the red frog crab Ranina ranina, locally known as “curacha,” from Balut Island, Sarangani, Davao Occidental, were the primary goal of this study. The carapace width (CW), carapace length (CL), abdomen width (AW), abdomen length (AL), propodus length (PL), dactylus length, and body weight were assessed. A total of 60 samples were sexed based on the shapes of the abdomens and examined in the laboratory. At the same time, the species' body weight was also measured. Most females of R. ranina have a larger body size than males. This is due to differences in growth patterns, food availability, and size of maturity. In terms of body weight, females of R. ranina are typically smaller, reaching a maximum of 400 g, whereas males can attain a total body weight of up to 900 g. It is important to note that males must be large enough to dig female crabs out of the sand to reproduce successfully. The allometric regression model describes changes in soft tissue content (or total animal weight for crustaceans) relative to carapace width or length. This result is consistent with the general trends of scaling with body size in animals.