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.