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.

This study investigated seasonal variation in the abundances and size distribution of shrimp species in Western Port Bay, Victoria from July 1977 to January 1980. Four species, Macrobrachium intermedium, Pontophilus candidus, Hippolyte caradina and Chlorotocella leptorhyncus, were sampled using a beam trawl as described in the record 'The ecology and trophic role of caridean shrimps in the eelgrass community of Western Port, Victoria' (File identifier: 268431c0-f18e-11dc-aaae-00188b4c0af8). Individuals in each sample were counted, identified, sexed, size measured (total length, carapace length), and reproductive state of females noted. The relationship between body size and ash-free dry mass was obtained in order to calculate the standing crop and productivity of each species. M.intermedium was the numerically dominant shrimp species in the eelgrass. Mean densities of P.intermedius and H.cardian were 20-50% and 3-4% less abundant than M.intermedium, respectively. Maximum abundances of M. intermedium and P.intermedius occurred early in the year and coincided with the recruitment of large numbers of juveniles. Densities of H.caradina showed high variability between years. Low capture efficiency of C.leptorhyncus meant that this species was excluded from the analyses.

This study investigated the ecology of caridean shrimp in eelgrass habitats in Western Port Bay, Victoria from July 1977 to January 1980. The study sites were located on the Churchill Tidal Flats on the northern side of Phillip Island, which are dominated by the eelgrass species, Heterozostera tasmanica and the cardiean shrimp species, Macrobrachium intermedium, Pontophilus candidus, Hippolyte caradina and Chlorotocella leptorhyncus. Benthic trawls were used to sample the shrimp populations at an offshore (Site A) and inshore (Site B) eelgrass site. Another site on a mudflat (Site C) was sampled to determine the movement patterns of shrimps between the mudflats and adjacent subtidal eelgrass areas. Sampling was undertaken every 1 to 2 months at night time during high tide. Plankton tows were used to monitor the presence of larval stages of shrimp in the water column. Details of each experiment and results are described in the related records.

This study investigated the influence of environmental factors on the distribution of shrimp in Western Port Bay from July 1977 to January 1980. Water temperature, salinity and oxygen concentrations at the sediment surface were measured from a boat at high tide during the field sampling (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). Additional measurements of low tide surface water temperature over the mudflats, sediments below the mud-water interface, and surface waters of the large, permanent channels between mudbanks were obtained. Above-ground vegetation cover was sampled monthly for 12 months at Site A. The water temperature in the eelgrass ranged from 10 to 24 degrees Celsius during high tide and from 5 to 31 degrees Celsius during low tide. Salinity was close to fully marine throughout the warmer months of 1977-78, but fell to lower levels during the cooler months of 1978, presumably as a result of higher rainfall in the latter period. Oxygen concentrations were above 6 ppm at all sites during high and low tide sampling. The dry mass of above-round eelgrass was spatially heterogeneous with few changes in these patterns between seasons.

Brown shrimp, Farfantepenaeus aztecus, and white shrimp, Litopenaeus setiferus, were held were held under natural light conditions before experiments. Experiments were conducted in twelve rectangular tanks (58 cm x 149 cm) under fluorescent lighting (7-10 microEinsteins/sec/sq m). Shrimp were placed in randomly-assigned tanks the day before observations were initiated at 0730 h, the lights were turned on, and observations of thepercentage of shrimp burrowed ( 1/2 of their body beneath the substrate) were recorded hourly (starting at 0830 h) throughout the daylight hours. For both species, burrowing rates decreased significantly as the substrate became courser. Brown shrimp burrowing was marginally affected by salinity with the lowest burrowing rates at 5 ppt white shrimp burrowing was not significantly affected by salinity. Large brown shrimp burrowed more than small and medium sized shrimp, but size did not significantly affect burrowing of white shrimp. The presence of a fish predator in the tanks did not affect burrowing of either species, but hunger level significantly affected burrowing for both species.

This study investigated the influence of predation on the distribution of shrimp in Western Port Bay from July 1977 to January 1980. Predation by birds was determined by analysing the diets and feeding rates of the most abundant wading birds in the area, the Royal Spoonbill (Platalea regia), the White-faced Heron (Ardea novaehollandiae), and the Sacred Ibis (Threskiornis aethiopica). Predation by fish was determined by examining the gut contents of fish caught in the beam trawls. The shrimps found in the gut contents were identified and, where possible, sexed and carapace length measured. This study found that the major consumers of shrimps were the scorpaenid, Gymnapistes marmoratus (Australian Cobbler) and the short-headed worm-eel, Muraenichthys breviceps. The Royal Spoonbill feed almost solely on M.intermdieum, whereas the other 2 species of waders feed mostly on infauna. The larger-sized individuals, which tend to be females, are subject so higher predation pressure than other groups within species.

This study investigated the influence of predation on the distribution of shrimp in Western Port Bay from July 1977 to January 1980. Predation by birds was determined by analysing the diets and feeding rates of the most abundant wading birds in the area, the Royal Spoonbill (Platalea regia), the White-faced Heron (Ardea novaehollandiae), and the Sacred Ibis (Threskiornis aethiopica). Predation by fish was determined by examining the gut contents of fish caught in the beam trawls. The shrimps found in the gut contents were identified and, where possible, sexed and carapace length measured. This study found that the major consumers of shrimps were the scorpaenid, Gymnapistes marmoratus (Australian Cobbler) and the short-headed worm-eel, Muraenichthys breviceps. The Royal Spoonbill feed almost solely on M.intermdieum, whereas the other 2 species of waders feed mostly on infauna. The larger-sized individuals, which tend to be females, are subject so higher predation pressure than other groups within species.

Artificial substrata were used to investigate the patterns of establishment and change in the structure of a subtidal, marine epifaunal community at Portsea, Victoria from October 1975 to November 1979. Sessile invertebrate species and mobile species that significantly affected the distribution and abundance of the sessile species were the focus of the study. Experiments examining variability in recruitment and community development, species competitive ability, and the effects of predation on the epifaunal community at Portsea are outlined in the related records.