Exotic species introductions pose a significant threat to native ecosystems, and have the potential to cause declines or even extinctions in native species. However, despite a series of favourable conditions, an introduced species may not be able to successfully establish itself if the number of individuals released into the new environment is too few. Founder effects such as genetic bottlenecks are well documented and can result in a loss of allelic richness in the population, reducing the adaptive potential of the species. In comparison, native populations that have not undergone a genetic bottleneck tend to have greater allelic richness and can therefore have a more complex genetic structure than introduced species occupying the same environment.

This work explores differences in genetic diversity and population structure between two estuarine species found in Victoria, the invasive yellowfin goby, Acanthogobius flavimanus and the native blue spot goby, Pseudogobius sp. Mitochondrial diversity in Victorian yellowfin gobies is compared to samples from several potential source populations in Japan, and assessment of a similar region in blue spot gobies gives insight into diversity and population differences between native and invasive species.

Since both species have been identified as potential bioindicator species for monitoring estuarine health, this work is important in providing an understanding of population dynamics and potential adaptability of the yellowfin goby to local conditions in Australia. Sequencing information may also be used in future studies to assist in characterising genetic differences between the eastern and western morphs of the blue-spot goby.