Check your state regulations before you practice with gill nets. Not legal in some freshwater areas. <img src="/images/graemlins/blush.gif" alt="" />
In fact, read your state regulations before you do any type of hunting or fishing. (A google of "your state DNR Fishing Regulations" will probably get you close.) Limits, size restictions, seasons and types of equipment allowed vary from state to state.
Of course, if you are lost and starving use what you have and hope the game warden shows up to arrest you.