Bill Cody has really good questions and suggestions for you. Last summer he posted some links that describe successful fishing for them.
I have 5 big ones, 36" to 42" long in my 1/4 acre pond. They hardly dent my elodea forest. They will come near the dock when I'm feeding. It would be an absolute piece of cake to take them out with a 12 gauge loaded with coarse shot, say #2. Remember to aim slightly low as the refraction of light passing through water makes them appear higher than they really are. If I were shooting a surface slurper, I'd hold right at the base of its head. I wouldn't shoot if the fish were 4" or deeper under the surface. The concussion from the shot load hitting the water may help stun a target, too.
Have fun. And cook them up and report back. They are reportedly the most abundant farmed fish in the world for human consumption.