Fish kill the result of ‘natural causes’

(Photo supplied)

By Jeremy Sollars

A fish kill in parts of the Condamine River in recent days is understood to be the result of natural causes, mainly related to a ‘fresh’ flow of water from last week’s storms but also in part the drought.

Up to 100mm fell late last week above Killarney in parts and produced a sudden flow in the Condamine, which in turn resulted in a change of temperature as far downstream as The Scots PGC College weir in Warwick.

According to Ed Kemp of the Warwick District Fish Stocking Association the temperature change is known as “cold water aversion” and some fish species – like Bony Bream – are particularly susceptible.

But the dead fish observed at the Scots weir, and at the Backhouse Bridge across the Condamine at Killarney, have also included Murray Cod and Yellowbelly and some of the pest species European Carp.

While daytime temperatures have been in the mid to high 40s in recent days, a sudden flow in the river can result in cold water temperatures a metre or more below the water’s surface.

Ed Kemp said lower than normal oxygen levels in the river and turbidity or muddy conditions – as a result of the drought and low river level – would have compounded with the temperature change to cause the fish deaths.