ANÁLISE DO CRESCIMENTO ALOMÉTRICO NO CARANGUEJO-UÇÁ, Ucides cordatus (DECAPODA:OCYPODIDAE), NO ESTUÁRIO DO RIO COREAÚ, CAMOCIM, CEARÁ

Abstract

In the present paper a number of morphometric characters of the mangrove crab, Ucides cordatus, are analyzed with the aim of identifying the occurrence of functional maturity as determined by its allometric growth. The database is made up of 322 individuals (193 males and 129 females) sampled bimonthly in the period from January, 2004 through January, 2005, on the Coreau River estuary, Camocim county, Ceara State. Taking the carapace width (CW) as the independent variable, the following dependente variables were measured: carapace length (CL), length of the bigger claw’s propod (LBC), width of the bigger claw’s propod (WBC), length of the smaller claw’s propod (LSC), width of the smaller claw’s propod (WSC), and length of the second left-hand pereiopod (L2P). For males the gonopod length (GL) and for females the abdomen width (AW) were also measured. Regression lines were fitted to the morphometric data by means of an equation of the type ln Y = ln A + b ln X. In males the relative growth was characterized as positive allometric in L2P/CW, LBC/CW, LSC/CW, WBC/CW and WSC/LC; and negative allometric in CL/CW and GL/CW. In females, the relative growth was characterized as isometric in the relationships CL/CW, L2P/CW and AW/CW ; positive allometric in LSC/CW and LBC/CW; and negative allometric in WSC/CW and WBC/CW. The general conclusion is that the occurrence of sexual dimorphism depends upon the attainment of a functional maturity by means of a positive allometric growth in the length and width of the propod of both claws, and in the length of the second left-hand pereiopod of male individuals.