Lethal trip over the dam

Last month, Allan Lugg was camping at the caravan park near Burdekin Falls Dam in northern Queensland. In his own words Allan "was doing a bit of iNaturalisting - looking for critters to take pics of and add to my record collection as well as get a bit of exercise". To this end Allan headed downstream, where about a kilometre below the dam, he observed 4 large (900-1000mm) dead Barramundi on the bank. He postulated that the fish died as a result of injuries received while going over the dam wall in the recent flood.
Allan stated, "The dam was still spilling while I was there. It was obvious that flows had been much higher (3-4m) during preceding weeks judging by the silt left on rocks and vegetation. The bottom of the spillway has a number of flow splitters (concrete pillars - see left image below, courtesy of CSIRO) that are intended to dissipate the energy, and it also discharges onto large rocks. I suspect the fish came over the spillway during the high flow (attempted downstream spawning migration perhaps) and sustained injuries from hitting the rocks or flow splitters and then washed up downstream.
Allan said that he walked about 1km of riverbank - so there may have been a lot more dead fish further downstream. He recalled a similar thing happened to Australian Bass downstream of Tallowa Dam 15 or 20 years ago."
Sadly, Allan's observation of dead Barramundi downstream of a dam is not a one-off. View a newspaper article about dozens of large Barramundi dying after going over Peter Faust Dam (right image above).
Thank you Allan for uploading this interesting observation and for your thoughts on the sad demise of these fish.
Lähettänyt markmcg markmcg, 18. heinäkuuta 2022 08:16

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Sadly the same thing has been seen at Hinze Dam on the Gold Coast. There are signs up saying the authorities know and are working on a solution. Not sure how this can be remedied.

Lähettänyt marzipan2 5 kuukautta sitten (Lippu)

Thanks for your comment @marzipan2. I agree that fish passage, both upstream and down, is a huge issue to which considerable time and effort has been devoted, not always successfully. @sascha_schulz may wish to comment.

Lähettänyt markmcg 5 kuukautta sitten (Lippu)

Agree. Downstream passage of fish over high dam walls has an accepted/argued level of mortality. This is often documented in that particulars Dam' License of Operation (or similar) .

The solution is to create fish passage of larvae/fry/juvi/adult fish to replenish upstream populations. And there is a LOT of work happening that never gets into the news.

Lähettänyt sascha_schulz 5 kuukautta sitten (Lippu)

Thank you for your informed comment @sascha_schulz. :)

Lähettänyt markmcg 5 kuukautta sitten (Lippu)

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