SCIENTISTS are warning people not to release pet fish into lakes after discovering an invasive tapeworm never previously recorded in WA in two feral fish species caught from a northern suburbs lake.
The Murdoch University researchers say the discovery of the Asian fish tapeworm indicates a serious potential danger to native freshwater fish, and are urging that measures are taken to control their spread.
PhD researcher Cindy Palermo discovered a writhing mass of tapeworms when dissecting goldfish and carp that fish biologists David Morgan and Stephen Beatty pulled from a lake in the City of Joondalup earlier this year.
Ms Palermo discovered the intestines of some of the fish were completely blocked.
Associate Professor Alan Lymbery, who is the Centre for Sustainable Aquatic Ecosystems director at the university’s Harry Butler Institute, said the tapeworm could potentially spread to native fish species.
“The Asian fish tapeworm is a very serious pathogen of cultured fish like carp and goldfish and it could be even worse for native fish,” he said.
“Infection is usually fatal in young fish and those of a small size.
“The pathogenic effects of introduced parasites are frequently more pronounced in native wildlife which have not had prior exposure.”
The Asian fish tapeworm has spread to more than 200 fish species throughout the world via aquarium or pond releases.
Prof Lymbery leads a group at Murdoch that has been discovering more serious pests co-invading with introduced fish.
He said the discovery underlined the importance of not releasing unwanted pets like goldfish or carp into ponds or rivers.
“These alien species can impact water quality, disturb habitat and compete with native species, as well as introducing disease and parasites,” Prof Lymbery said.
To report an aquatic pest, call FishWatch on 1800 815 507.