Stomach contents of Australian snubfin ( Orcaella heinsohni ) and Indo‐Pacific humpback dolphins ( Sousa chinensis )

In Australia, snubfin (Orcaella heinsohni) and Indo-Pacific humpback (Sousa chinensis, hereafter humpback dolphins) dolphins are found in coastal waters of Queensland, Northern Territory and north Western Australia (Parra et al. 2002, 2004). Interactions between dolphins and gillnet fisheries and shark nets set for swimmers protection have led to both bycatch and direct killing of snubfin and humpback dolphins in Australia (Harwood et al. 1984, Harwood and Hembree 1987, Paterson 1990, Hale 1997, Gribble et al. 1998). It is unknown if these interactions are, at least in part, due to dolphins foraging on prey that are targeted by commercial fisheries; however, their foraging ecology remains largely unknown. A comprehensive understanding of the feeding ecology of snubfin and humpback dolphins is needed as a first step towards establishing their role as consumers, their potential effects on ecosystem function, and identifying potential conflicts with fisheries. Stomach content analyses of marine top predators are a valuable tool for identifying predator dietary needs and preferences (Gannon et al. 1997; Santos et al. 2001b, 2004, 2006), providing information on predator’s distribution (MacLeod et al. 2003), detecting foraging behavior and diving capabilities (Clarke 1996), identifying resource partitioning (Dolar et al. 2003) and interspecific competition (Spitz et al. 2006), and assessing potential interactions with commercial fisheries (Santos and Pierce 2003, Pierce et al. 2004). The available information on the diet of Australian snubfin and humpback dolphins is limited to a qualitative assessment conducted in the late 1970s (Heinsohn 1979). This assessment was incomplete because of restricted diagnostic techniques available at the time for identifying hard parts (e.g., otoliths,