I find it very interesting the volume of misinformation and lack of knowledge about deep water rockfish.
This fish is not a yelloweye, nor is it a protected species of rockfish. Properly identifying the bottom fish you catch is the first step in protecting our sport fisheries. Huge areas of the ocean are being closed down to us because of misinformation about bottom fish stocks.
Hook and Line fishing at 900 feet deep is very possible with today's technologies... between high strength braided line and electric reels, there are more and more people targeting fish at these depths. Most specifically black cod. It is not unreasonable to hand reel at 900 feet (We fish halibut & Ling cod at 600 - 700 feet offshore every year) but I agree that it is a whole lot of work.
The effect of the swim bladder expanding as the fish comes up from the depths is called Barotrauma. The expansion of the swim bladder causes the stomach to protrude out the mouth and the eyes to bulge. The faster you reel up the fish, the works the condition is. When released, these fish cannot dive down to their depths because of this and end up being bird food.
Venting used to be the accepted way to release these fish... a sharp poke behind the fin and the gases would escape, allowing the fish to dive... This is not a good idea. Popping the stomach that is protruding from the mouth will not vent the fish... all you are doing is poking a hole in the fishes stomach and releasing no gasses.
Recent research indicates that a descent device is the best way to release these fish and the survival rate may be upwards of 80%. There are several models out there and are easy to use. The key to successfully releasing bottomfish is to get them down to depths where the pressure will naturally compress the swim bladder back to it's original size. Lots of good information at this link.
http://www.nwr.noaa.gov/stories/2013/18_2013_06_19_preventing_barotrauma.htmlHaving said all that.. yes, in the circumstances in which this fish was caught, I would have kept this fish.