Actually, a lot of the more whacky environmentalists HATE man-made reefs. I'm a saltwater fisherman (DE, MD mostly) and the envirowhackos fought tooth-and-nail against a plan to dump hundreds of old NYC subway cars to form artificial reefs off NJ...and they won (Delaware ended up taking them.) Touted a bunch of crap about the "asbestos" in the cars (like asbestos underwater does anything to anybody, or anything.)