Imaudigger, I think it's safe to assume those are different types of pumps from dredges. And the airdrop fish probably have a low survival rate. I'm not too worried about farmed, planted fish anyway.
"Decades after Reese and Faist first dropped their fish, I talked to a biologist who witnessed a similar event while snorkeling in one of the lakes of the Sierra Nevada. Many of the fish were ripped in half on impact, he told me, and many others were so stunned they immediately sank to the bottom, never to recover."
I understand where you're coming from, and I'm pretty much on your side, just the examples aren't really the best.