The population biology of the exploited crab Ucides cordatus (Linnaeus, 1763) in a southeastern Atlantic Coast mangrove area, Brazil

Abstract

Ucides cordatus (Linnaeus, 1763), found in mangroves along the Brazilian coast, is an artisanal fishery resource harvested as a source of income and for subsistence. A 12 month study of U. cordatus was conducted in a mangrove area of the southeastern Brazilian coast to estimate the growth, longevity, sex ratio and population density of the crabs. A total of 1024 crabs (505 males and 519 females) were sampled. Carapace width (CW) ranged from 49 to 90 mm (mean ± SD: 71.2 mm ± 6.0) for males and from 52 to 83 mm (69.3 mm ± 4.9) for females. Males dominated the largest CW classes. The asymptotic size (CW∞) and the asymptotic weight (WW∞) were estimated as 93.4 mm and 305.5 g, respectively, for males and as 87.1 mm and 221.5 g, respectively, for females. The estimated maximum longevities were 17.6 years for males and 15.7 years for females. The males (k = 0.17, Φ = 1.171) and females (k = 0.19, Φ = 1.159) showed similar growth rates. The mean density was 0.41 ± 0.19 burrows m−2. Of this total mean density, 85.8% corresponded to the immediate harvesting potential and 14.2% to the future harvesting potential. Given that U. cordatus is a long-lived species that grows slowly, an appropriate strategy for the management is crucial to ensure the sustainable exploitation of this resource.