I did this same exercise 5 years ago on the Logan River.
Only I spent on average 1 - 2 nights a week for over a month.
I found almost the same as Webby is describing.
The by-catch was very minimal most of the time.
In terms of table fish caught - you could count them on one hand for the entire month.
There was one or two nights when the herring were in large numbers - I'd estimate 20 - 30kg caught and thrown back per night but it made it impossible to sort prawns when they were that thick so the skipper moved to another area to get away from them.
On average, every time the net contents was dropped on the sorting tray there would be a total of 3 to 6 bait species – gar, pike, mullet.
On average the catch was 40 - 60kg of mixed prawns per night - it was considered by the skipper to be about average catch.
Some nights were as low as 20kg and other just over 100kg.
On average they were getting $6 a kg for their catch at that time – primarily sold as bait.
I was not on the boat during the banana prawn season but it was suggested this is the time of year they make good money – if the prawns turn up.
The reason for these comments is to suggest that, from my personal experience, what Webby encountered was pretty typical in terms of by catch.
Dave ><>