Byron Shire Council says it is ‘possible’ that the opening of Tallow Creek on Wednesday night (November 22), which resulted in a massive fish kill, might have been a natural occurrence. But an ecologist who visits the site regularly doesn’t think so.
Several homes that back onto Tallow Creek experience backyard flooding when the creek level rises beyond a certain point.
A council spokesperson said in a media release on Friday (November 24) that in recent weeks the water levels in the creek estuary, which is intermittently closed and open, had been rising and ‘residents had been asking the council to open it to the ocean’.
But because the level had been hovering below that at which the council is licensed to open it, officers had instead been keeping a watching brief.
It’s claimed some residents took it upon themselves to open the estuary, resulting in a dramatic outflow of water and a drop of the water level by more than a metre.
Fish were stranded, flapping about on dry land or in deoxygenated water from upstream, leading to almost the entire population of fish in the creek being killed, according to ecologist Dailan Pugh, who visits the creek regularly.
Opened at midnight
The disaster that followed the illegal opening of Tallow Creek estuary. Photos Dailan Pugh
Mr Pugh told Echonetdaily that people had been trying to open the Tallow Creek estuary ‘for the past two weeks,’ adding, ‘their efforts bore fruit late on Wednesday night’.
‘The data for Tallow Creek (at the bridge) show the opening starting at midnight,’ he said.
A regular visitor to Byron, Falco, who visited the estuary for a swim around midday Thursday told Echonetdaily he found water ‘rushing like a river incredibly fast’ into the sea.
‘The water was brown and churned up and sand was caving in around the edges.
‘It was nothing like the placid lake I remember,’ said Falco, adding a council staffer on the scene told him neighbours had dug a trench ‘because water was running into their backyards’.
Mr Pugh said that by sunset ‘the developing disaster was apparent’.
He said that by Friday afternoon the NPWS had cleaned up the thousands of dead fish around the mouth of the estuary, ‘and by Saturday morning they had been replaced by thousands more’.
‘The fish kill now appears to be complete,’ he told Echonetdaily on Saturday, ‘with little signs of life left in the estuary.
‘There are no longer a multitude of fish gasping for breath around the edges of the estuary as they all appear to have died. A solitary mud crab has taken to the shore, apparently the water was even too toxic for it. A few live fish survive in the outflow channel.
‘Many thousands of fish have been killed, and the countless multitudes of fingerlings gone’ he said.
‘It is a complete ecological disaster. The estuary will need to start from scratch to rebuild its ecosystem.
‘This is the price for reducing flooding of a few people’s gardens that were planted in the estuary’s wetlands.’
Mr Pugh said there needed to be an emergency response protocol in place in ‘for next time people initiate a fish kill’.
‘We need to know what action, if any, we can take to reduce the slaughter.
‘In the meantime there needs to be a concerted effort to find those responsible and bring them to justice, to stop them doing it again.’
How fish kill happened
Byron Shire Council’s flood and drainage engineer, James Flockton, said the fish kill was the result of the dramatic drop in the level of the estuary combined with deoxygenated swamp water flowing into it from upstream.
‘In this case the fast flow of water out of the creek quickly removed the oxygenated water from the system and appears to have caused the fish kill,’ he said.
‘Water with low oxygen levels is often called “black water” and is a common cause of fish kills.
‘Council has engaged Australian Wetlands Consulting to conduct water sampling in Tallow Creek over the next six days and staff will also be downloading water quality data at the footbridge to better understand how the water quality changed during the opening process.’
Anyone with information on how the estuary came to be opened is urged to contact Mr Flockton on (02) 6626 7300 or the Cape Byron office of the National Parks and Wildlife Service.