"Recently it has been reported that trawlers operating in the Northern Territory Prawn fishery use hoppers on the deck of the vessel to assist in sorting of the catch. The prawns and fish are dumped on a grid above the hopper. The small animals fall into the hopper which is filled with sea water. The large ones are released over the side. The prawns sink to the bottom and land on a conveyor belt. These are brought out and transferred to a sorting conveyor belt. The fish swim around in the hopper until the prawns are sorted. The water is released and the fish are quickly moved along the conveyors back into the sea. No information is presently available regarding the eventual survival of the released fish. (S Kennelly Pers. comm.). A system of sorting in the water has also been reported as being used in the New South Wales prawn fishery where the mixed catch in the cod end of the trawl is emptied into a water tank, the live prawns settle at the bottom and the fish are taken from the top and floated off."
Food 7 Agricultural Organisation - United Nations
All well and good Pickers, but let's not lose sight of the fact that these hoppers were not developed for the elimination of by-catch purely because the pro sector wanted to "polish up it's act". They were developed primarily to keep the prawns in a better condition ie to prevent damage to the prawn and prevent them drying out in the tropical heat. They weren't developed for benevolent reasons, they were developed purely with profit in mind.
There is documentary evidence showing that by-catch elimination was/is co-incidental and that the motives for the development of hoppers was the intent to produce a better product, and not purely to eliminate by-catch.
The pros seemed to have claimed it as an "environmental move" when it was in fact, motivated purely by economic necessity ie profit.
The latest research that I have found (which I can't seem to extract from a pdf file atm to post here) aims for a "60% survival rate using hoppers, as opposed to 70% mortality rate without"
Now some may see that as a vast improvement, after all, they're aiming to double the survival rate of by-catch, but what shouldn't be overlooked is that there is still an estimated 40% mortality rate, even with the use of hoppers..................40% of total catch landed is what exactly? 3000 tons of by catch in Moreton Bay alone according to DPIF and CSIRO figures equates to 1200 tons of dead by-catch even if all boats were fitted with hoppers.
Don't get me wrong, I agree for the need of a pro fleet and I agree that in many ways, by-catch is inevitable. What I don't agree with is that by-catch coming from breeding and nursery grounds. That is my stance, and always has been.
kev