Seasonal zonation patterns of the sandy beach bivalve Donax deltoides (Bivalvia: Donacidae) in subtropical eastern Australia

Abstract

Seasonal low tide zonation patterns of the sandy beach bivalve Donax deltoides are described from eleven beaches in subtropical eastern Australia. Ten low tide transects were sampled at equal along shore intervals along the length of each beach. Three quadrats were sampled at each of seven across shore levels on each transect, from the high tide drift line, across the intertidal zone and to the bottom of the low tide swash zone. Zone counts showed that D. deltoides shifted towards the low tide swash zone in summer and buried in the intertidal zone in winter. It is proposed that D. deltoides moves down shore in summer to avoid thermal stress in the intertidal zone. This seasonal pattern is important when planning surveys for this species.