FOOTBALL-SIZED goldfish are travelling hundreds of kilometres each year as they invade the state’s waterways.
Murdoch University researchers have used strategically placed acoustic receivers to examine the movement patterns of the pest in the Vasse River.
Stephen Beatty and researchers from the Centre of Fish and Fisheries found goldfish displayed a significant shift in habitats during breeding season, with one fish moving more than 230km in a year.
“The goldfish population in the nutrient rich Vasse River has existed for over two decades and has the fastest known individual growth rate of this species in the world,” Dr Beatty said.
“The results of this study will have important direct management implications, enabling more strategic development of effective control programs for the species such as targeting migratory pathways.”
Goldfish are native to eastern Asia but are considered one of the world’s worst invasive aquatic species, with at least 76 invasive freshwater fish species introduced to rivers in Mediterranean climate regions around the world.
Defined as an alien species introduced to Australian freshwater bodies, goldfish can enter river systems after being dumped from aquariums into catchment lakes.
Once the fish become established, their eradication is often difficult, which is having a significant impact on Australian ecosystems.
“Once established, self-sustaining populations of alien freshwater fish often thrive and can spread into new regions, which is having a fundamental ecological impact and is a major driver of the decline of aquatic fauna,” Dr Beatty said.