Density and size of structure of Nerita scabricosta (Mollusca: Neritidae) in the intertidal zone of islands of southeastern Gulf of California, Mexico

Currently in the northwest of Mexico there are no studies on the density and sizes of the snail Nerita scabricosta, , which is classified as a potential resource. Density and size of N. scabricosta gastropod were recorded of intertidal of islands of the two bays (Mazatlan and Navachiste) of Sinaloa, Mexico. For each island the snaild were counted (50 m2) 2 ) and 25 organisms were collected at random, the width Wi (mm) and weight W (g) were recorded. In Mazatlan bay, the highest density was Venados island (66.1 ind<middle dot>m-2) -2 ) and the lowest in Lobos (2.9 ind<middle dot>m-2), -2 ), the mean in Wi was 17.6 +/- 5.1 mm and in W 6.0 +/- 4.8 g. In Navachiste bay, the highest density was San Lucas island (2.7 ind<middle dot>m-2) -2 ) and the lowest El Metate (0.2 ind<middle dot>m-2). -2 ). The mean in Wi was 26.1 +/- 4.5 mm and in W was 14.8 +/- 6.2 g. The density of N. scabricosta was higher in islands of Mazatlan (P=0.017), P =0.017), but on average (sizes and weight), the snails of the Navachiste islands were higher (P=0.298). P =0.298). In addition, the relationship between Wi and W of N. scabricosta indicated positive isometric growth.