Edward River fish tale

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Wednesday 24 October 2012 -  NSW Fisheries
National Water Week – Edward River fish tale

It appears that one of Australia’s most renowned inland fish species – the Murray Cod – is finding life a little easier thanks to the recent installation of a fishway in the Edward River.
NSW Water Commissioner, David Harriss, said to allow migration of native fish the Edward River Offtake Regulator Fishway was constructed as part of the Living Murray Environmental Works and Measures Program.
As part of the construction a fully automated, self tuning, remotely accessible monitoring system was installed.
Mr Harriss said the fishway was opened in March this year and since then there has been many detections of tagged fish recorded by the monitoring system.
“When the database was checked it showed that 91 per cent of detections at the fishway have come from a single fish - a Murray Cod that had been initially caught and tagged in March 2006 in the Murray River one kilometre downstream of where the Edward River leaves the Murray River.”
“When it was tagged over six years ago it measured 982mm.”
“This particular fish was first recorded at the Edward River fishway in May this year and has shown plenty of activity since its initial detection, especially with the increase in flows and water temperature, although there was no recorded activity during the winter months.”
“This Cod has passed through the fishway many times. Most interesting is that when the gates of the Edward River regulator are fully open and there is unimpeded passage to fish movement through the regulator, this Cod seems to prefer to move through the fishway.”
Mr Harriss said the monitoring data also indicated that on the first time it passed through the fishway the fish swam from the exit, downstream in the river through the open regulator and then reappeared at the fishway entrance in a time of twelve minutes and fifty-seven seconds.
“More recent recordings have shown the same behaviour from this fish on a regular basis.”
“This large Murray Cod and at least one other are regular visitors to the Edwards River fishway, being detected at or in the fishway on almost a daily basis.”
He said the second Murray Cod recorded was tagged at the Edward River Offtake regulator in February 2006 and measured 373mm.
“The monitoring has proved that big Cod do use ‘designed in Australia’ vertical slot fishways.
Until now this was only thought to happen through anecdotal evidence,” Mr Harriss said.