Size class, density, and distribution of Uca tangeri (Eydoux, 1835; Decapoda: Ocypodidae) in the mangrove ecosystems of Senegal

Abstract

This study focusing on the decapod brachyuran Uca tangeri is the first of its kind in Senegal. It was carried out in the mangroves of the Senegal River delta, the Saloum islands, and the Casamance estuary. The modal cephalothoracic length (L; mm) is between 24 and 25 mm in Saint -Louis, 18 and 19 mm in the Saloum, and 16 and 17 mm in Casamance. The modal cephalothoracic weight (Wei; mm) oscillates between 31 and 32 mm in Saint-Louis, 24 and 25 mm in the Saloum, and 25 and 26 mm in Casamance. Whether it is the relation Lc/We or that of the height/weight, the allome-tric growth of crabs is negative (b <3). Likewise, the correlation coefficient values revealed a strong relationship (R >0.8) among the biometric parameters. The average crab density in the mangrove is between 1.3 and 1.6 crabs per square meter. The strong presence and abundance of Uca tangeri suggest this species does not have a preferential spatial distribution.