Increases in east Australian humpback whale populations, specifically in areas where sightings were previously infrequent, highlight the importance of understanding the usage patterns and habitat preferences for resting grounds along migration pathways.  This study investigates the spatio-temporal distribution of humpback whales in Jervis Bay, Australia, based on pod composition, providing insight on the role of this shallow coastal embayment for mother-calf pods during the southern migration to polar feeding grounds.  Geographical citizen science based sighting data collected by commercial whale-watch operators during the 2007 to 2010 migration seasons were mapped to examine variations in bay usage and pod composition.  Differences in the distribution patterns of mother-calf and non-calf pod sightings were examined using spatial cluster analysis.  The impact of observer bias introduced through non-specialist volunteer collected data was assessed. Mother-calf pods showed a significant preference for the shallow waters of Jervis Bay during October and November, indicating the bay may function as a preferred resting location during their southern migration with important marine management implications. However, if data sourced from whale watching platforms are to be used in spatial models, methods are needed to evaluate the impact of potential observer bias on results and the implications for marine management decision making.