Catfish bred rapidly, colonised the shallow waters of lakes, and fed on the same things as trout and kura, Mr Atkinson said.
"Introduced lake weeds are also a significant threat to our lakes and the recreational enjoyment of them...the public needs to be constantly vigilant of the risk of new weed incursions."
Read more:
• 'Landmark decision' for future of Lake Rotorua
Deputy chairman Warren Webber said he hoped the outcome of the symposium would be to improve community awareness and to influence policy at a national level.
A keynote speaker is Dr Lindsay Chadderton, a New Zealander based in the United States, who is an international expert in the use of eDNA for the detection of pest fish.
Nick Smith, Minister for the Environment, will speak and Rotorua MP Todd McClay will chair a session, as well as other speakers from Niwa and the Department of Conservation.
Mr Webber said the programme was "pretty intense" but people appreciated the breadth of the content.
"People can pick and choose the areas they are interested in, each session is at the forefront of environmental issues."
Mr Atkinson said the annual Mayoral Environmental Forum, to be held as part of the symposium, would feature Sir Rob Fenwick and investigative journalist Rod Oram speaking about sustainability.
Mr Atkinson said the forum was aimed at the public and the $20 cost went towards planting a reserve in Rotorua.
The community had a "significant" part to play in helping clean up the lakes, Mr Atkinson said.
"[They] are the eyes and ears of our natural environment. Much has already been achieved in terms of lake water quality but we can't take that progress for granted."
He said the key thing was the community was informed.
"People drive change and question the government... [they] should come along if they care for the lakes and want to see the catfish eradicated, to demonstrate their support, want to see far better control of invasive lake weeds and they care Lake Tarawera is deteriorating and needs a lot more care."
Lakeswater Quality Scientific Symposium 2017
WHAT: Symposium looking into catfish, invasive lake weeds and nutrients issues facing Te Arawa lakes.
WHERE: Millennium Hotel.
WHEN: Thursday, August 31 and Friday, September 1.
For more information, registration and ticket prices visit www.lakeswaterquality.co.nz