Morphometric Analysis of Coconut Crab (Birgus latro) of Meos Ambower Island, Fam Islands, Raja Ampat

Abstract

Objective: This study aims to analyze the length–weight relationship of coconut crabs (Birgus latro) on Meos Ambower Island, evaluate sexual dimorphism in morphometric characteristics, and determine growth patterns based on regression analysis. Research Design: Observational research with a quantitative approach using morphometric analysis and inferential statistics. Place and Duration of Research: Meos Ambower Island, Fam Islands, Raja Ampat, West Papua, May-August 2024 period. Methodology: Sampling was carried out by purposive sampling at night by tracing the natural habitat of coconut crabs. A total of 100 individuals were measured in carapace length parameters using digital calipers and body weight using digital scales. Gender determination is carried out through the identification of gonopodore morphology. Analysis of the relationship between weight and length using a linear regression model with the equation W = a + bL, evaluation of sexual dimorphism using t-test independent samples, and growth patterns were determined based on regression coefficients. Results: The regression model yielded the equation Weight = -966.37 + 154.98 × Length with an R-squared of 0.575 and a p-value of 6.33E-20 indicating a significant relationship. The t-test revealed a significant difference in carapace length between males and females (t = 3.405, p = 0.001) but not in body weight (t = 0.811, p = 0.419). The sex ratio shows a dominance of 65% males compared to 35% females. The regression coefficient indicates a negative allometric growth pattern. Conclusions: The length–weight relationship of the coconut crab (Birgus latro) showed a strong correlation with significant sexual dimorphism in carapace length. This morphometric data is an important baseline for the sustainable management and conservation of canary crab populations in Raja Ampat.