Fish habitat charity OzFish has reported alarming scenes in northern New South Wales, where numerous fish have been observed gasping for air or found dead. This distressing event is particularly evident in the Northern Rivers and Mid North Coast regions, following flooding caused by the severe weather from ex-Tropical Cyclone Alfred, which predominantly affected south-east Queensland.
The situation has worsened, with new reports emerging from the Clarence River near the Queensland border and the Macleay River in the Mid North Coast of NSW, both noting a significant number of dead fish. Cassie Price, the CEO of OzFish, indicated that the phenomenon known as “blackwater” is likely responsible for the fish deaths. Blackwater occurs when flooding washes organic materials into waterways, leading to an oxygen depletion as these materials decompose, ultimately suffocating aquatic life.
Among the casualties are various fish species, including flathead, bream, and whiting, along with prawns and other marine creatures. It has also been reported that mud crabs and eels are fleeing the contaminated waters. Testing conducted last week revealed dangerously low oxygen levels in the affected waters; while healthy levels should be around 5mg of oxygen per litre, areas such as the Richmond River have plummeted to a mere 0.4mg per litre.
To combat these severe fish kills in the future, Price has advocated for the restoration of swamplands adjacent to rivers, suggesting that healthy wetlands can act as natural filters to mitigate the impacts of blackwater. Immediate action is imperative to prevent further fish mortalities and enhance the resilience of aquatic ecosystems.
Local residents witnessing dead or struggling fish are urged to report these occurrences to OzFish. Amid these environmental challenges, communities along the coast are facing mounting pressures from frequent natural disasters, leading to soaring insurance and living costs, as highlighted by recent reports.