Published online by Cambridge University Press: 27 March 2009
In the first description of the population structure of the cockle Cerastoderma glaucum, a preliminary stock assessment and spatial distribution have been investigated in the Bou Ghrara Lagoon. The main results collected about this species in the coastal zone of the lagoon from 2003 through to 2004 have been recapitulated. A total of 671 cockles was collected, treated and the demographic structure of this species was studied. In terms of geographical occupation, maps of the population distributions were drawn. They showed that this population has a significant fluctuation in the colonized surface, which was roughly divided into five sites. The consequence was a remarkable biomass which represented 220 tons of fresh weight (average 15.53 g m−2) and high abundance levels reaching over 156 million individuals. The distribution of the species has also been investigated in consideration with the size which varies markedly according to location, while the shell length ranged between 6 and 29 mm. Additional factors influencing the population distribution are discussed and it is concluded that bottom characteristics, food potential (organic matter content of the sediment, phytoplankton rates and seagrass organic matter) and physicochemical factors were the fundamental factors controlling the spatial distribution of C. glaucum.