I surrender!!!
But it won't be a Lenthall's escapee. If a 1 metre barra escaped Lenthall's the water level would drop 6 inches.
No I'm not guessing. I do have some hard data about what happened with the Awoonga Great Escape. It doesn't fit with your "probably not" comment. It only relates to barra 850mm or more.
In the first escape (Feb 2011), 164 escapees bigger than 850mm were tagged in the Boyne below the dam wall.
36 of them were 1000mm or better with the largest 1170mm. Big fat ones.
Of those tagged, 12 made it as far south as the Mary to be recaptured. That's 12 of those tagged or 7.3% with 4 reported recaptures from 1000mm to 1150mm.
Time taken to recapture varied from 27 days (2 of them) to 1000 days. Some got south in a hurry and some took their time.
So, if 7.3% of tagged ones got through, its pretty safe to say that 7.3 % of the untagged ones that went over the wall got though as well.
7.3% of 13,500 (after deaths) makes about 1000 Awoonga escapees got through to populate Kolan, Burnett, Elliott, Burrum, Sandy Straits and Mary. I reckon that some went even further south to Brisbane etc though no tag recaptures were reported. One tag was reported recaptured 315 km north 788 days later
That was only 1 overflow event. There were 3 overflows.
THAT'S what my opinion is based on.
You're right in that my knowledge of Mary River fishing is limited. I've done some fishing there but only for king on a handline from an old roadbridge between Mboro and Hervey bay ( the old Saltwater Creek bridge is it?)
But you don't have to have any of the local knowledge to know that about 1000+ barra from Awoonga went down that way. You local guys do the re-capturing and reporting and that's where local knowledge is indeed needed.
You fellas are not going to convince me and I'm not going to convince you.
So I'm happy with a truce.