Residents around Newcastle’s Throsby Creek are concerned, after thousands of dead fish were found floating in the water in Wickham and Tighes Hill.
The Environment Protection Authority and the Department of Primary Industries say there’s no evidence pollution or industrial discharge is responsible.
It’s alleged critically low dissolved oxygen levels in the water are responsible, due to a build-up of leaf litter, as well as heavy rainfall and high temperatures.
But residents say they’d like to see further investigation into the issue.
There’s also concern the dead fish could draw bull sharks into the shallow parks of the creek.
Newcastle MP Tim Crakanthorp says the community’s “extremely keen to see the reason behind [the fish kill]”.
“I’ve been contacted by a number of local residents living around the water, and they are deeply concerned, as am I,” Mr Crakanthorp said.
“I know the community’s very upset by this, and a quick analysis and an understanding of the issue would be very helpful for the Throsby community and Newcastle as a whole.”