EXPLAINED: Why dead fish keep appearing in Tweed waterways
A FISH kill has occurred in Kingscliff's Cudgen Creek, the second in Tweed waterways within a week.
The large fish kills have been reported to the Tweed Shire Council, with a spokeswoman blaming the "blackwater'' events on decaying vegetation from the heavy rains and floods depleting oxygen levels in the water.
And it might not be the last of the mass deaths.
The Cudgen Creek fish kill last Friday came just a few days after thousands of juvenile fish and prawns washed up lifeless in Cudgera Creek Estuary at Hastings Point.
According to the council, it is difficult to predict how long the fish kills will last.
"In each case, there has been a spike in the number of fish deaths which occurs when very poor water quality affects that part of the creek that is supporting most fish," the spokeswoman explained.
"Some fish die, some will leave the area, but the numbers each way will depend on many factors including the fish species and its size, the nature of the incoming 'bad' water and even tide and sea conditions.
"While the poor water quality will remain for some time, hopefully the fish won't be trapped in it and therefore we won't see any more major kills."
The spokeswoman said as there is still a significant amount of water sitting on the coastal flood plains and with showers persisting, the water will continue to deoxygenate.
"Tides over the next week are small so where won't be major flushing of tidal water into the upper reaches of the creeks," she said.
"It's likely that water quality will take quite a few weeks to fully recover in the coastal estuaries but hopefully we won't see ongoing fish kills in that time."
The council confirmed it will continue to work with NSW Department of Fisheries about the issue.