Effect of flooding on estuarine bivalve populations near the mouth of the Hopkins River, Victoria, Australia

The densities of two common intertidal/shallow subtidal bivalves, Soletellina alba and Arthritica helmsi, were sampled in vegetated and unvegetated habitats of the Hopkins River estuary on three occasions during the  autumn/winter 1995.Winter flooding coincided with mass mortalities of the infaunal bivalve S. alba, but not A. helmsi. Mortalities were apparent for individuals living deeper in the sediment (≈35 cm) in vegetated and unvegetated habitats, but small S. alba (<1mm) were less susceptible to mortality than larger individuals (>1mm). Mortalities were similar across different habitat types and sediment depths, and at multiple sites within close proximity to the estuary mouth.