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.