0.80) but there was a relationship in the abundance of N. americana for the three sampling stations (ANOVA, n=10, P<0.05) since the highest density of this species was recorded in the inner zone of the estuary. Significant differences in salinity were found between the three sampling stations for those dates when N. americana was present (ANOVA, n=10, P<0.05) but it could not be demonstrated that this variable is related with the spatial distribution of this species in the estuary (covariable, P>0.15)]]>