Community of bivalve molluscs in a bed of Thalassia testudinum in the Cariaco Gulf, Sucre State, Venezuela

The seasonal variation of the bivalve mollusks was described in a bed of Thalassia testudinum in the town of Los Cachicatos (10 degree 03' 36'' N and 63 degree 46' 40'' W), in the Cariaco Gulf, Venezuela, from November 2000 to December 2001. The samples were collected with a 0.015 m super(2) PVC sampler and the sediment was sifted through a 1 mm mesh. A total of 601 organisms belonging to 5 orders, 14 families, and 29 species were collected. The mollusk monthly density ranged between 364 and 1.117 ind.m super(-2) (X= 557.64 plus or minus 157.08). The monthly species richness dropped to its minimum expression in December 2001 (9) and its maximum value (16) was reached in July of the same year (X= 11 plus or minus 2). The species diversity ranged between 2.6 and 3.43 bits.ind super(-1). Five species remained constant during the study period, the most abundant Chione cancellata, Brachidontes exustus, Modiolus squamosus, Arca zebra, and Anadara notabilis. No significant differences were observed between the biomass values of T. testudinum and the intermonth density of individuals, nor was there any significant correlation of the phanerogam biomass with the abundance of mollusks and the species richness, due possibly to the homogeneity of the environmental characteristics in the study zone.