Each summer adult mulloway (Argyrosomus japonicus) aggregate in areas of the Swan River each evening to spawn, producing a hours-long chorus each time. Passive acoustic monitoring has been used to observe the aggregation in Mosman Bay for several years, however, the chorus is not produced at exactly the same location each night, but varies with time. In October, 2016, 12 acoustic recording systems (8 OceanInstruments Soundtraps and 4 Centre for Marine Science and Technology Underwater Sound Recorders) were deployed at various sites around the Swan and Canning River system to record underwater sounds, from Fremantle Port to Belmont Racecourse and near Shelley Bridge. The SoundTraps recorded continuously for the duration of the deployment while the CMST recorders were set to a 4 of every 5 minutes duty cycle, sampling at 48 kHz and 8 kHz, respectively. The recordings included the choruses and calls of the mulloway at various sites, as well as signals from resident dolphins and passing vessels. The chorus levels have also been compared to previous years’ data to investigate how the fish movement may relate to environmental factors, such as solar, lunar and tidal patterns, as well as salinity and temperature. This presentation will highlight the various received sound pressure levels attributable to the mulloway choruses over time to illustrate the ability of passive acoustics to map movements of vocal fish species.