Condition factor and carapace width versus wet weight relationship in the swimming crab Callinectes danae Smith 1869 (Decapoda: Portunidae) at the Santa Cruz Channel, Pernambuco State, Brazil

Marina De Sá Leitão Câmara De Araújo Araújo,José Jonathas Pereira Rodrigues De Lira

doi:10.1590/s0104-64972012000100005

Marina De Sá Leitão Câmara De Araújo Araújo, José Jonathas Pereira Rodrigues De Lira

Open Access

https://doi.org/10.1590/s0104-64972012000100005

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Abstract

The present work aims to study the size vs. weight relationship and the condition factor of a commercially important crab, Callinectes danae, from an estuarine complex located at Pernambuco State, Northeastern Brazil. After sampled, the specimens were measured on their carapace width (CW; mm) and weighted on their wet weight (WW; g). A total of 1,635individuals of C. danae were analyzed, being 881 males (53.8%) and 754 females (46.2%). Males were significantly larger and heavier than females (p < 0.05), the expected pattern to many crabs. The relationship WW vs. CW, described through the potency equation, was allometrically positive for both males (b = 3.12) and females (b = 3.02), a result also observed in other swimming crabs. The mean condition factor of males was 8.0 10-5 ± 1.5 10-5, and that of females was 11.5 10-5 ± 2.8 10-5, being significantly higher in females (p < 0.05), due to the fact that female gonads are heavier than that of males. The condition factor oscillated throughout the sampling year, for both sexes, which was related to the reproductive cycle.

Highlights

The Crustaceans are widely used in studies of relative growth, in function of their rigid exoskeleton and discontinuous growth (Du Preez and McLachlan, 1984; Leite et al, 2006)
The b is the allometric constant, which expresses the analogy between these two variables, and the constant a represents the degree of fattening of the species, and is called the condition factor (CF)
According to Satake et al (2009), this relationship is an important tool in studies of biology, physiology and ecology, specially of species with commercial value (LeCren, 1951; Froese, 2006; Mohapatra et al, 2010), since it allows the estimation of the weight when only size measures are available and allows the comparison between different populations (Gomiero and Braga, 2003)

Summary

Introduction

The Crustaceans are widely used in studies of relative growth, in function of their rigid exoskeleton and discontinuous growth (Du Preez and McLachlan, 1984; Leite et al, 2006). According to Satake et al (2009), this relationship is an important tool in studies of biology, physiology and ecology, specially of species with commercial value (LeCren, 1951; Froese, 2006; Mohapatra et al, 2010), since it allows the estimation of the weight when only size measures are available and allows the comparison between different populations (Gomiero and Braga, 2003) This relation can be used as a quantitative indicator of the healthiness or “well-being” of the species in its environment, through the condition factor (Vazzoler, 1996)

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