Tweed Shire Council says it is working to determine the cause of a fish kill in a section of Vintage Lakes at Banora Point/Tweed Heads South but believes a drop oxygen levels to be the culprit.
Council maintenance gangs removed a number of dead fish on Friday afternoon from the downstream end of Vintage Lakes (near Port Drive and west of Fraser Drive) after reports from the public.
Commercial fishermen are now cleaning up hundreds of fish affected by what is believed to have been low dissolved oxygen levels in the urban lake.
TSC roads and stormwater manager Danny Rose said the vast majority of the fish killed were large mullet, also known as bull mullet.
‘The Vintage Lakes component of the Banora Point western drainage scheme is actually a storm water system,’ Mr Rose said.
‘Although the lake and storm water system are designed to collect and manage urban stormwater run-off, it is unlikely the cause is toxicity.
‘If this was the case, many more species would have been affected as well as mullet.
‘High temperatures in the past months resulting in warm water temperatures within the shallow lake, combined with the breakdown of organic matter, could have contributed to the low dissolved oxygen levels.’
‘Although unlikely, Council is testing water samples for the presence of pesticides and has also undertaken inspections of the local sewer network to rule out any leaks.’
A similar fish kill occurred in the same location in January 2005, but summer storms hindered test results and the exact cause could not be determined.