Victoria’s Environment Protection Authority (EPA) is warning that rising temperatures are likely to cause an increase in fish deaths being witnessed in flood-affected parts of the State.
Chief Environmental Scientist at EPA, Mark Taylor said native fish needed water that contained about 20 per cent dissolved oxygen (DO), but the State’s water monitoring network was showing dissolved oxygen levels below this in several locations, particularly in the north.
“The toll on Victoria’s inland aquatic wildlife from the floods is tragically going to grow as we see a combination of flood affected waters and warmer weather both of which will reduce dissolved oxygen levels,” Professor Taylor said.
“Our advice is to continue to avoid contact with flood waters where possible because of the risk of contamination, not to eat any dead fish found in the waters and in the first instance, report dead fish sightings to EPA at 1300 EPA VIC (1300 372 842).”
He said eight rivers and water systems were experiencing low DO which may lead to fish deaths.
Professor Taylor said this included Broken Creek, where fish deaths have already been reported and which had experienced very low levels of DO (less than 10 per cent).
“The main stem of the Murray River is experiencing low DO downstream of Barmah [Forest],” the Chief Scientist said.
“Fish deaths are expected here but the high flow rate may mean the fish are not highly visible, except in slow flowing areas,” he said.
“DO dropped low for a few days in the Goulburn River at McCoys Bridge, between Shepparton and the Murray.”
However, Professor Taylor said DO in the Campaspe River appeared to be satisfactory and was acting as an important fish refuge, with fish able to move from the Murray up the Campaspe River.
He said low DO was also observed in the Loddon River, Gunbower Creek, Wimmera River and News South Wales rivers.
