1) Considered rec fishing because it uses a rod and reel, hook and line. People from shore can easily do it and all it is really is a meat fishery.
2) First of all I m not 100% confident in the study. They only held fish for 48 hours I believe, and then released them. This year they radio tagged a bunch in the ocean and will be tracking them, and I also believe will be tagging some of the C and R fish from this study as well.
If it is indeed a 90% survival rate there could be a few reasons. First of all, when bottom bouncing the fish is generally hooked on the outside of the mouth (Maxillary), therefore doing less damage (such as tearing, bleeding, gut hooking, etc) to the fish' mouth. This method has started to be used in fly fishing as well using a slider fly and a trailer hook to get the fish on the side of the mouth, rather than inside. Also, the gear used by bottom bouncers on the Fraser is generally quite heavy, so fish can be brought in quickly without being played out.
Fish taken by a more "sporting method" are generally taken on things like bait, spinners, spoons, etc. In these cases the fish attack or grab the bait deeply and can become bleeders. Often smaller hooks would be used as well to get the "stealth approach" so it is easier for the fish to swallow the hook and get injured.