Erosion and dams threaten barramundi and prawn fisheries

Barramundi caught at Shady Camp freshwater in Northern Territory. Credit: Marcus Finn
Barramundi caught at Shady Camp freshwater in Northern Territory. Credit: Marcus Finn

Kilometre-wide erosion gullies eating their way across Australia’s northern landscape are proving likely culprits as the main source of the sediments that are flushed into the Gulf of Carpentaria each year, possibly smothering prawn and barramundi breeding and rearing habitats.

Researchers involved in the Tropical Rivers & Coastal Knowledge (TRaCK) program are trying to find out more about northern Australia’s rivers in the face of demands to develop them as southern water supplies run dry.

Other TRaCK research is looking at how floods into the Gulf affect the catch of prawns as freshwater flooding into the estuaries lowers the salinity and pushes the prawns out to sea where they are harvested.

The natural river flows connecting the tiny headwaters, waterholes, massive floodplains and estuaries are important for maintaining the reproductive and feeding habitats for fish like barramundi that move upstream during the wet season.

If the northern rivers are dammed, or if water is taken out for irrigation, this is likely to upset the natural movements of barramundi and it will mean less freshwater flowing into estuaries, with a probable reduced catch for prawn fishers.

For more information: TRaCK, Ruth O’Connor, Tel: +61 (7) 3735 5094, r.oconnor@griffith.edu.au, www.track.gov.au

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