Please report any fish death incidents or observations to the Fishers Watch Phoneline on 1800 043 536
Fish kills are defined as a sudden mass mortality of wild fish.
Fish kills can occur at any time although data indicates fish kills are more likely to occur in summer or following sudden changes in temperature.
Recent reports of fish kills are included in the table below and we will update the table as we receive reports.
Some of the key causes of fish kills are outlined in the information below.
Blackwater occurs naturally over time when leaf litter and woody debris build up on the floodplain and then get washed into the river system during a flood. It’s an important part of the aquatic food web as it provides food for insects which feed fish, frogs and other aquatic wildlife.
When there is a prolonged dry period, the leaf litter and organic matter on the floodplain builds up until the next flood event. This can result in a significant amount of organic matter returning to the river with any big flushes of water after prolonged drought, making blackwater events more likely.
When there is a lot of organic material washed into the river, its rapid decay can consume dissolved oxygen from the water. If dissolved oxygen drops to very low levels, this can cause ‘hypoxic’ water which can be stressful for native fish and can lead to fish kills.
To notify the department of potential blackwater events email email@example.com or to report a fish kill, contact the Fishers Watch Phoneline on 1800 043 536.
Find information on the impacts of bushfires on native fish.
Stratification is when the surface of the water heats up more than the deeper water. That warmer layer tends to be warm and well-oxygenated compared to the deeper water that is colder and oxygen-depleted.
Updated: 15 December 2020 (3pm)
Location and date kill observed
Cause and extent
Murray Darling catchments in NSW
Peel River, Tamworth (7 December)
Report of 10 to 20 dead fish including European Carp and Murray Cod.
Cause was episodic rainfall event the preceding weekend that caused short and sharp flow in the river. This can cause a rapid reduction in dissolved oxygen levels due to large volumes of organic material entering the river system.