Dr Stephen Beatty and a team from the Centre for Fish, Fisheries and Aquatic Ecosystems will be undertaking a comprehensive fish survey in the Vasse-Wonnerup Ramsar wetland system and its rivers.

Previous work by the research team has identified introduced fish and crayfish as key threats to the ecological health of south-western Australian aquatic ecosystems.

The number of species of introduced freshwater fish now outnumber native freshwater fish species in these ecosystems.

Little is known about the native fish fauna in the Vasse-Wonnerup wetland system however, a number of invasive species in the Vasse River are of concern, including goldfish, eastern gambusia and the yabby.

“These pose a serious threat to this internationally recognised wetland,” Dr Beatty said.

“They compete with native species for food and habitat, they introduce diseases, disturb habitat and are predators of native fish and their eggs.

“As part of the survey, the project will identify pest species hotspots, prioritise the threats posed by those species and undertake control programs to reduce their ecological impact.

“This will help us to mitigate the many impacts that pest fish and crayfish have on unique aquatic ecosystems such as the Vasse-Wonnerup.”

The project, led by Dr Beatty, Dr James Tweedley and Associate Professor Alan Lymbery, will have a strong emphasis on community education to help prevent further introductions of pest species into unique south-western Australian waterways.

“Invasive species often enter the river system through people dumping aquarium fish into waterways. Overflow from ponds is another major factor in their introduction,” said Dr Beatty.

“People really need to consider how they dispose of unwanted fish – they should be taken back to an aquarium shop rather than released into the river.