"However the species is now regarded as near-threatened on the International Union for Conservation of Nautre (IUCN) Red List, so keeping track of how populations are faring over time is of key importance," Mr Williams said."
"We already have good informtion about the Benalla population that has been built up over several years.
"This is extremely valuable when it comes to management issues, such as planning te drawdown of water in the lake from time to time to eliminate the invasive aquatic weed Cabomba.
"However we really need more volunteers to keep the monitoring up to scratch.
"Standardised visual scans don't take huge amounts of time - participants only need to spend five minutes at each site.
So we hope people will come along and find out what is involved - it's easy, enjoyable and rewarding"