Workshop to showcase newly completed fish lock

An information workshop to showcase the world’s only operating Deelder Lock is being held at Balranald on Wednesday 12 November.

The workshop, funded by the Environmental Trust, is being held by NSW Department of Primary Industries (DPI) and State Water on Wednesday 12 November, at the Balranald Ex-Servicemen’s Club, 10am-3:30pm.

NSW DPI research scientist at Narrandera Fisheries Centre, Dr Lee Baumgartner, said attendees would have the opportunity to listen to presentations from fisheries experts and then attend a hands-on demonstration of the Deelder lock at Balranald Weir.

“The construction of weirs has reduced the ability for native fish to undertake important upstream and downstream migrations vital for spawning, feeding and dispersal,” he said.

“To overcome these migration barriers, scientists can construct fishways (or fish ladders). These are basically a fish-friendly channel that bypasses a dam or weir.”

Dr Baumgartner said the Deelder lock was an innovative fishway, with the technology initially developed in Belgium in 1950, and adapted to suit conditions at the Balranald site in 2003.

“The Deelder lock operates in a similar manner to a navigation lock for boats and is operated on either a one, two or four-hour cycle.

“Fish are attracted to the fish lock entrance by providing a water flow as a migratory cue. They then enter a chamber which fills with water to help fish move freely to the weir pool and continue their migration,” he said.

Until recently, the lock was operated manually, which meant fish could only migrate when staff were present on site. The Environmental Trust funded the installation of automation equipment and fish passage is now permanently available.

Dr Baumgartner said an initial fish migration assessment identified more than 14,000 fish and shrimp (from 11 species) moving through the automated fishlock in 39 days.

“The success of this fish lock has now led to the design being installed at several sites on the lower Murray River,” he said.

All community members with an interest in native fish are welcome to attend the workshop, but it is important to register an interest at the Narrandera Fisheries Centre on (02) 6959 9021 to secure a place.

A light lunch will be provided for those who register by Friday 7 November.