Perth metro lakes surveyed for introduced fish

Apr 22, 2014 by Michelle Wheeler
One of the species discovered the convict cichlid (Amatitlania nigrofasciata), had not been recorded previously in WA. Credit: Dean Pemberton

Fisheries officers are attempting to eradicate introduced fish from some Perth waterways following research that suggests less than five per cent contain only native species.

Initial results from a survey of lakes in the metropolitan area suggest that more than 80 per cent have only introduced fish, while between five and 10 per cent contain a mix of both native and feral .

Department of Fisheries acting principal research scientist (freshwater) Rodney Duffy says the survey has so far uncovered more species of introduced fish than native fish.

He says at least two introduced fish discovered – the convict cichlid (Amatitlania nigrofasciata) and a species of platy – had not been recorded previously in WA.

At Lake Marmion in Myaree, an attempt is underway to eradicate the eel-tailed catfish (Tandanus tandanus) after laboratory tests revealed the fish is carrying a bacterial disease never seen before in Australia.

Department of Fisheries aquatic biosecurity officer Bruce Mackay says the catfish is an aggressive predator and was carrying Pseudomonas anguilliseptica, also known as red spot disease.

He says the population was well established in the lake and was "breeding like crazy".

Mr Mackay says in the 12 months leading up to the eradication attempt fisheries officers conducted a "fish down", in which thousands of catfish were removed using nets.

Then in February the fish-specific toxin rotenone was applied to the lake.

"Prior to the eradication attempt in just one night's netting we pulled out 500 fish," Mr Mackay says.

"Directly after the rotenone application with an even greater number of nets… we only pulled out five fish and they were tiny, less than a 5 cent coin in length."

The next step is to remove the catfish completely and Mr Mackay hopes to one day restock the lake with .

Prevention key to management

He says it is important to focus on prevention to stop introduced species becoming established in the first place.

"If a pest species becomes established and starts spreading into a full river system the chances of eradication are just about zero and the costs would be astronomical," Mr Mackay says.

Dr Duffy says the survey project has assessed more than 400 water bodies since the start of last year and he hopes the total number, 600-700 in all, will be completed by the end of this year.

He says a lot of the feral species seem to be aquarium releases but with others it was less clear how they happened.

"For instance carp in a lot of the lakes, often they might be put in by a community member or a developer to enhance the amenity," Dr Duffy says.

Explore further: Tiny number of Asian carp could be big problem for the Great Lakes

add to favorites email to friend print save as pdf

Related Stories

Survey set to prove northern fish disease-free

Mar 05, 2014

A joint study about to begin will determine whether populations of freshwater catfish in the country's tropical and sub-tropical regions are free of the Edwardsiella ictaluri bacterium.

Recommended for you

Brother of Hibiscus is found alive and well on Maui

11 hours ago

Most people are familiar with Hibiscus flowers- they are an iconic symbol of tropical resorts worldwide where they are commonly planted in the landscape. Some, like Hawaii's State Flower- Hibiscus brackenridgei- are en ...

Boat noise impacts development and survival of sea hares

13 hours ago

While previous studies have shown that marine noise can affect animal movement and communication, with unknown ecological consequences, scientists from the Universities of Bristol and Exeter and the École Pratique des Hautes ...

Classic Lewis Carroll character inspires new ecological model

Jul 30, 2014

Inspired by the Red Queen in Lewis Carroll's Through the Looking Glass, collaborators from the University of Illinois and National University of Singapore improved a 35-year-old ecology model to better understand how species ...

Saving seeds the right way can save the world's plants

Jul 30, 2014

Exotic pests, shrinking ranges and a changing climate threaten some of the world's most rare and ecologically important plants, and so conservationists establish seed collections to save the seeds in banks ...

User comments : 0