Some ecological aspects of the gecarcinid land crab, Cardisoma armatum Herklots, 1851 (Crustacea, Brachyura, Gecarcinidae) from the estuarine region of the Comoe River, Côte d’Ivoire

Abstract

Cardisoma armatum Herklots, 1851 is a land crab endemic to tropical coastal ecosystems and represents an important fishery resource. C. armatum was collected using traps at the eastern region of the Ebrie lagoon and the estuarine region of the Comoé River in 2009 during the high rainy season extending from mid-May to mid-July and in low dry season from mid-July to September. Some biometric parameters are measured to determine some aspects of population structure and condition of this edible crab. Sexual dimorphism was confirmed with the major chelae of male crabs reaching larger sizes than those of females. The sex ratio that varied with the sampling periods was associated with migrations occurring during the breeding season. Positive, negative, and positive allometric growth patterns were observed for the carapace length-total weight relationship, respectively, in males, females, and the population as a whole. For the carapace width/total weight relationship, negative allometric growth was observed, respectively, in males, females, and the whole population. Our data show an evidence of a serious problem of recruitment in the population of this crab related to degradation of the habitats and heavy harvesting pressures, highlighting the necessity of developing and implanting management and protection strategies of this crustacean.