I also have caught "gallons" of smelt during the spring spawning run using large square nets off piers in Lake Ontario and with long handled hoop nets near rapids at the inflow of inland lakes. Catching them is lots of fun, cleaning 1000's of them is not so much.

I have never used hooks/line but when the spawn is on the water is filled with smelt and I am sure just jigging the line would catch many.

Mike