Those are not dip nets-do an image search to see the differences between nets.
There's been some controversy about allowing Smelt netting from the Seawall, in the past people would just leave what they didn't want on the walkway, garbage, dead fish you name it and there was talk of closing it altogether then for a while in the old pamphlet they used to give out there was an appeal for people to leave the Seawall clean and it seems to have worked.
As to rod/line fishing I've noticed the Guys who fish there now are quite courteous and neat that's good to see it's a beautiful place to fish even if there's SFA to bother with.
A small, fine net on the end of a 6' - 8' stick? That's what I've seen them use.
I watched a video of a guy using a cast net near Second Beach to catch smelt. Also near Ambleside pier.