There are some U-tube videos that show netting grass shrimp in conditions you describe. Shallow water with lots of weeds and grass. As I recall (been a while since I watched some of them) they were getting on the order of 25 grass shrimp with a dip net as they drug it through the grassy areas.
I would think a wetland type pond without a lot of predators would be ideal for grass shrimp. But my personal experience is severely limited. Hopefully will know more about raising them later this summer when I see how they do in my forage pond. It is not the perfect environment to raise them.
