River oxygenation helps fish thrive

Fish being surveyed in the Swan Canning Riverpark
Fish being surveyed in the Swan Canning Riverpark Parks and Wildlife

A black bream tracking project in the Swan and Canning rivers is showing benefits of the Liberal National Government's investment in providing artificial oxygenation in the upper reaches of the rivers.

Environment Minister Albert Jacob said the tracking of 55 tagged black bream had found they avoided areas of the rivers that had low oxygen levels, confirming river oxygenation was an important strategy for improving river water quality and survival of aquatic species.

"This research is showing that black bream, a popular recreational fishing species, favour areas of the river that are well oxygenated, which suggests that artificial oxygenation is beneficial during periods of low oxygen, particularly during summer and autumn months," Mr Jacob said.

"This is important because improving water quality with oxygenation relief not only helps aquatic animals and other wildlife, but it supports recreational fishing, and ensures the rivers are attractive for recreation and natural assets for the whole community."

A network of 30 acoustic receivers, or listening stations, along the rivers has been recording data from the tagged black bream since April 2016.  About 740,000 detections were received during the first 116 days.  

The data has revealed that black bream prefer habitat with large woody debris and brackish water.  They tend to inhabit deeper parts of the estuary during the daytime, except in low oxygen conditions, and shallower waters in the evening.

Oxygenation plants at Guildford and Caversham provide relief for up to 10km of the Swan River.  The State Government is upgrading the oxygenation plant at Bacon Street in Wilson to provide oxygen along 4.5km of the Canning River upstream of the Kent Street weir.

This project will continue to collect data from the black bream over the next year to further evaluate the effectiveness of the oxygenation plants in providing a refuge for fish, and help guide the plants' efficient operation.

Fact File

  • The research is being conducted by Murdoch University in partnership with Parks and Wildlife and co-funded by Recfishwest
  • Recreational fishers helped collect almost a third of the tagged fish
  • Since 2008, the Liberal National Government has invested $12.5m in oxygenation plant construction and upgrades, including maintenance, operation and monitoring
  • The 2016 assessment of the Swan Canning estuary based on the Fish Community Index of estuarine conditions is available here