A BLACK bream tracking project in the Swan and Canning rivers is showing the 55 tagged fish involved are avoiding areas of the rivers with low oxygen levels.
Environment Minister Albert Jacob said this confirmed river oxygenation was an important strategy for improving river water quality and survival of aquatic species and highlighted the benefits of the government’s investment in providing artificial oxygenation in the upper reaches of the rivers.
Oxygenation plants at Guildford and Caversham provide relief for up to 10km of the Swan River.
Mr Jacob said the research showed black bream, a popular recreational fishing species, favoured areas of the river that were well oxygenated, which suggested that artificial oxygenation was beneficial during periods of low oxygen, particularly during summer and autumn months.
“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,’’ he said.
Mr Jacob said a network of 30 acoustic receivers, or listening stations, along the rivers had been recording data from the tagged black bream since April 2016.
About 740,000 detections were received during the first 116 days.
The research is being carried out by Murdoch University in partnership with Parks and Wildlife and co-funded by Recfishwest.
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.
The State Government is upgrading the oxygenation plant at Bacon St in Wilson to provide oxygen along 4.5km of the Canning River upstream of the Kent Street weir.
The 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.
Recreational fishers helped collect almost a third of the tagged fish.
Mr Jacob said since 2008 the Liberal National Government had invested $12.5 million in oxygenation plant construction and upgrades, including maintenance, operation and monitoring.