Little is known about the biology and ecology of marine turtles in the Pilbara region of Western Australia and most potential habitat is unconfirmed and, therefore, undescribed. Understanding basic biological parameters at a regional level is critically important for effective long-term management.

Female sea turtles are promiscuous, with clutches of eggs often sired by multiple males and rates of multiple paternity varying greatly within and across species. We investigated levels of multiple paternity in loggerhead sea turtles (Caretta caretta) from three rookeries in Western Australia by analysing polymorphic species-specific genetic markers.

The Western Australian population of loggerhead turtles, Caretta caretta, is recognized as a single genetic stock (Dutton et al. 2002; FitzSimmons et al. 1996; Limpus 2008). Nesting spans approximately 520 km from Steep Point (southwest of Denham) to the Muiron Islands (northeast of Exmouth) (Baldwin et al. 2003). Dirk Hartog Island is close to the southern end of this range.