Impact of year of specimen collection on stable isotope signatures.

Temporal variation observed in δ13C and δ15N for the South Australian bottlenose dolphin (SABD) populations in Port Phillip Bay the Gippsland Lakes and the common bottlenose dolphin (CBD), determined by linear regression analysis (* indicates significance). The significant difference observed in Port Phillip Bay δ13C is likely confounded by sex of the specimen (with females being collected at earlier dates than males) rather than any temporal variation. No difference was observed in the δ15N of the Port Phillip Bay population and for either isotope value in the other SABD population in the Gippsland Lakes.