There is a Bowfishing Forum on this page which will cover most anything you need to know. As far as seasons, in Washington State there is no set season (open year round) although May thru August are the best months. Common Carp are legal to Bowfish, Grass Carp are protected, although rare to see one, they are not much different except shape and color of Head and tail ( at least the one i "saw"). Use of Gaffs are illegal, and game fish are off limits as well. Most major bodies of water fall under the above regs, but i would check the books for any special rules for ponds and smaller lakes before you shoot.
