Oh Upstream....I don't think so..well perhaps in the calm spots...We'll see..
Any other techniques? I am complete beginner on this spearfishing...but I'll try it out....next summer..

Yeah..and the river I am planning on diving is about 3m-8m deep and perhaps 20-30 meters wide...I can't be sure but I know that I don't want to get caught in the whitewater..that would hurt..