Population Structure of The Mangrove Crab Ucides cordatus (Crustacea: Decapoda; Brachyura) in the Estuary of the Mamanguape River, Northeast Brazil.

Abstract

The crab Ucides cordatus (Linnaeus, 1763) or ‘caranguejo-uçá’, as it is known in Brazil, is one of the most conspicuous and abundant components of the epibenthic macrofauna of Brazilian mangrove ecosystems and the most exploited resource by riparian human populations. It is aimed here to study the population structure of this crustacean in the estuary of the Mamanguape river, State of Paraíba, Northeast Brazil. The research was performed between August 2000 and September 2001. An area of 1600m2 was marked out through the mangrove habitat and the density of U. cordatus was determined by counting inhabited burrows. Three-hundred crabs were captured and biometrical and sexual ratio values were obtained. The mean density of inhabited burrows was 1.7 burrows m-2. Males crabs were larger than females and their sexual ratio was 1.85: 1.00. They mate between January and March. The low dimension of captured specimens and the low values of population density here obtained confirm the observation of crab gatherers that ‘caranguejo-uçá’ is decreasing in that mangrove area. It is suggested the need for a management plan aiming a sustainable exploitation of this important food and profitable resource. Key words: Ucides cordatus ⋅ Leaf-consuming crab ⋅ Mangrove ecosystem ⋅ Northeast Brazil