Diets of four shrimp species in eelgrass habitats, Western Port Bay, Victoria

This study examined stomach contents of shrimp sampled in the beam trawls in Western Port Bay from July 1977 to January 1980 (see parent record 'The ecology and trophic role of caridean shrimps in the eelgrass community of Western Port, Victoria', File identifier: 268431c0-f18e-11dc-aaae-00188b4c0af8). An evaluation was made of summer and winter diets of Macrobrachium.intermedium, Pontophilus intermedius and Hippolyte caradina. Chlorotocella leptorhyncus was not present in the summer samples, so only the winter diet of this species was determined. Food items in the stomach were identified and the size of intact specimens was measured. All items were counted and assigned to a taxonomic category at the lowest possible level. The relative volume of individual prey items and taxonomic groups was also estimated.

During summer, M.intermediaum fed on a mix of animals (small crustaceans, gastropods, and polychaetes) and plant matter, and during winter, the diet was mostly plant matter. Polychaetes were the abundant prey items in the stomachs of P.intermedius, representing close to 70% of the diet in summer and winter. Almost 70% of the overall volume of food consumed by H.caradina was plant matter with small crustaceans, gastropods and insects making up the remaining proportion of the food consumed. The amount of plant matter in the diet increased in the winter months. C.leptorhyncus was found to ingest approximately equal volumes of animal and planter material with polychaetes the most abundant animal prey. The plant matter found in all samples was mostly dead eelgrass tissue.