Population structure of the burrowing crab Neohelice granulata (Brachyura, Varunidae) in a southwestern Atlantic salt marsh/Estructura poblacional del cangrejo cavador Neohelice granulata (Brachyura, Varunidae) en una marisma del Atlantico sudoccidental

Neohelice granulata inhabits estuarine and protected coastal areas in temperate regions and is the most dominant decapod crustacean in the Bahia Blanca Estuary, Argentina. The population structure was studied during a year in a SW Atlantic salt marsh located in the Bahia Blanca Estuary. Crabs were sampled monthly from August 2010 to July 2011. The maximum observed density was 30 crabs [m.sup.-2] in February and 70 burrows [m.sup.-2] in May. The maximum carapace width (CW) was 32 and 27.5 mm in males and females respectively. Medium size crabs were between 16 and 20 mm CW. Significantly smaller sized crabs were observed at the lower intertidal regions (P < 0.05). The sex ratio was favorable for males and was significantly different from the expected 1:1 (P < 0.05). The recruitment of unsexed juveniles crabs (CW