Hinchinbrook fish-kill blamed on low dissolved oxygen levels in water

Low dissolved oxygen levels in water are being blamed for the deaths of large numbers of fish in Hinchinbrook Shire.

Photos of dead fish, most likely spotted grunter, washed up on Taylors Beach, Lower Herbert, Hinchinbrook, North Queensland. The cause of the mass fish kill has been blamed on low dissolved oxygen levels in the water. Picture: Supplied

Low dissolved oxygen levels in water are being blamed for the deaths of large numbers of fish in Hinchinbrook Shire.

In a social-media post on a Forrest Beach community Facebook page on Christmas Eve, a man who identified himself as James Smith urged locals to avoid anything caught in Victoria Creek.

He said he counted “hundreds of dead, decaying” barramundi, bream, mangrove jacks “and even sea snakes”.

Another poster reported seeing the same thing in the Enterprise Channel at Dungeness, Lucinda, although not in the same numbers.

A screengrab from a video of dead fish washed up on Taylors Beach, Lower Herbert, Hinchinbrook, North Queensland. The cause of the mass fish kill has been blamed on low dissolved oxygen levels in the water. Picture: Supplied

Brett Gossner, in the top comment, said fresh water, hot weather and small tides made for low oxygen levels in the creeks, which were “not good for the fish population”.

The Department of Environment and Science (DESI) are aware of the incident.

A spokesperson confirmed that the fish kill was believed to be due to low dissolved oxygen levels in the water.

Photos of dead fish, most likely spotted grunter, washed up on Taylors Beach, Lower Herbert, Hinchinbrook, North Queensland. The cause of the mass fish kill has been blamed on low dissolved oxygen levels in the water. Picture: Supplied

According to NQ Dry Tropics, heavy rain could lower oxygen levels “by washing soil and plants into the water”.

“Following a long drought, the extremely dry soil struggles to absorb much initial rainfall, and it runs off into the water”, a spokesperson said.

“As bacteria breaks down this organic material, it sucks up the dissolved oxygen in the water, leaving none for the fish.

“Fish need dissolved oxygen in the water to breathe through their gills, and in low-oxygen water this can lead to massive fish kills.”

Originally published as Hinchinbrook fish-kill blamed on low dissolved oxygen levels in water