The Torres Strait archipelago, located between Papua New Guinea (PNG) and northern Queensland, was once a land bridge but now forms a region of approximately 300 islands under present sea levels. Its close proximity to PNG presents a substantial risk of invasive freshwater fish entering northern Queensland via the Torres Strait. In addition, pest species from mainland Australia, such as cane toads, pose further threats to the biodiversity and cultural values of Torres Strait Islander communities.

Since 2018, TropWATER (James Cook University) has conducted environmental DNA (eDNA) surveys in partnership with Torres Strait Regional Authority (TSRA) Indigenous Rangers across multiple islands. Environmental DNA is a relatively recent method that enables the detection of rare or newly arrived species because it does not require visual or acoustic encounters. Instead, it relies on collecting trace DNA that organisms shed into their surroundings. TropWATER has developed a field protocol suited to tropical and remote areas that enables Indigenous Rangers to collect eDNA samples efficiently and with minimal training. This method has been successfully applied across northern Australia for detecting species of biosecurity and conservation concern.

Through the collaboration with TSRA, we obtained the first scientific evidence of Nile tilapia on Saibai Island, which was subsequently confirmed through netting. The monitoring program aims to detect early incursions of pest fish and cane toads that would otherwise remain unnoticed, enabling rapid response and eradication actions and supporting the conservation of local biodiversity.