I gig in saltwater, have tried lots of different types of poles. I also do some bowfishing, with a compound bow, and a crossbow.
Bamboo does make an excellent material for gigging poles, they also float if dropped overboard (those expensive aluminum or fiberglass poles will not) The only drawback to bamboo is that constant exposure to saltwater, temp changes, and UV light, causes it to start splitting.
Our local tackle shop sells fiberglass gig poles. Short of that, I think you could take a telescoping fiberglass paint roller pole and use that for gigging, and that might even work out better. To guarantee it will float if dropped overboard, blow a can of expanding foam inside the pole (this is about the only useful marine application for this type of foam, IMHO)