As said above several times, check with your state, but in Texas no game fish (meaning anything that has a limit) can be caught and kept (that is the kicker, and "kept") with a cast net. Doing around a dock, I would for sure follow that rule as everyone seems to have camera out and it will take that one person that see's you do it to turn that video in. Stick to the pole, but cast nets are fun. Now, if you are on a private lake that is another story. Also I say lake, but somewhere there is a definition of lake vs pond, but to me if I can put a boat in it, it is a lake!