I found this and thought I would share:
Should I reel in fish hooked in deep water quickly or slowly?
Fast! Contrary to popular belief, slowly reeling in a fish from deep water DOES NOT give a fish enough time to compensate for the change in pressure. Between 20 and 30 minutes may be needed for a fish to compensate for pressure differences between a depth of 30 ft and the surface. Instead, prolonging the time it takes to land and release a fish, increases its stress level. The tissues around the gas bladder are often capable of preventing the gas bladder from increasing in size for up to 5 minutes after the pressure outside of the fish decreases. Once a fish is in the boat, or on the ice, release it as quickly as possible to maximize its chance of surviving. The colder the water the better, especially surface temp.
It also states that bringing a fish from 60′ has a 50% chance off survival and from 30′ the chance of survial increases greatly.
Nate