Ladders to help Torrens wetlands fish breeding

Original story at ABC News: “Native fish ladders to help wetlands breeding in River Torrens“

Measures have been taken to support native fish numbers in the wetlands near the River Torrens outlet in Adelaide’s western suburbs.

Fish ladders have been built on weirs between Tapleys Hill and Henley Beach Roads.

They help fish movement to encourage breeding.

Project manager from the Natural Resources Management Board Steven Gatti said the ladders were to help the fish travel through the weirs at times of low water flow.

“The two ladders that we’ve recently completed are essentially … stepped concrete ramps, so to you and I they might look like a series of steps, but they’re very shallow graded steps and they’re full of rocks so that they allow water to trickle over those rocks and fish access up and down them as required,” he explained.

“We’ll be looking at undertaking further fish surveys in September of this year to make sure that the fish ladders are functioning. We’ll be able to tell by identifying the assemblages of fish that are present and the numbers in which they’re present.”

Taskforce reports

A taskforce set up by the South Australian Government to investigate mass fish and dolphin deaths has formally reported its findings.

An increase of 3-5 degrees Celsius in water temperature and an algal bloom were blamed for this year’s deaths of thousands of juvenile fish.

Vic Neverauskas from Biosecurity SA says the higher temperatures also contributed to juvenile dolphin deaths.

He said the dolphins died of morbillivirus, a part of the same family of viruses that causes measles in humans.

“When we get a heatwave, who’s the first ones to suffer? It’s the elderly and the very young,” he said.

“In this case the very young dolphins were stressed, that affected their immune system and they succumbed to the virus, which under normal circumstances they would have adapted and developed an immunity to.”