Crab Diets Differ Between Adjacent Estuaries and Habitats Within a Sheltered Marine Embayment

Portunid crabs contribute to significant commercial and recreational fisheries globally are commonly fished in estuaries and/or marine embayments, which amongst the most degraded of all aquatic ecosystems. Portunus armatus were collected seasonally between April February from five locations across three systems temperate south-western Australia. The dietary composition was quantified compared two (Peel-Harvey Swan-Canning) a sheltered embayment (Cockburn Sound) containing distinct habitats: shallow seagrass, sand deep sand. Overall, ingested large volumes bivalves (both live organisms dead shell), polychaetes, crustaceans (e.g., amphipods, small decapods), smaller teleosts, echinoderms plant material (seagrass, algae). Analysis Similarities showed that varied significantly among (two habitats within Cockburn seasons, with greater location than seasonal differences estuaries. Diets Sound seagrass due decapods teleosts bivalve shell consumed this habitat. Crabs both quantities those Sound. Seasonal greatest summer winter, more diverse range prey summer, whereas Peel-Harvey polychaetes other Swan-Canning, winter. diet Estuary current study 20 years previous documented change benthic macroinvertebrate fauna. Currently, consume high-calorie prey, i.e., instead ingest proportions calcareous previously. This marked shift parallels changes macroinvertebrates Estuary. availability appears be major factor influencing spatial temporal P. diets these coastal systems.