lconn4 wrote:Does anyone know why it doesn't occur in all bass at a certain depth?
To put it in a very basic way, because I'm certainly no marine biologist; it's the same as a SCUBA diver surfacing. If you exhale on the way up, nothing happens. Hold your breath as you surface, and you will explode your lungs.
If the fish has time enough during the fight to release the gasses from it's swim bladder, no problem. Usually you will see this swim bladder problem if you bring the fish up very quickly. Since we were tournament fishing, we didn't waste any time getting those fish to the boat.
My SCUBA skills are so rusty that I'll probably get the math wrong, but I believe every 15 feet equals one atmosphere (twice the pressure); so from 15 feet to the surface isn't really that noticeable to a fish (or human), but from 30, 45, or 60, it gets progressively worse.
This is also why SCUBA divers have to make decompression stops after deep dives. It allows the gases in the blood and organ tissues time to expand as well. Come up to quickly and you get the "bends."
If you've ever gone deep sea fishing, this is especially noticeable. I remember catching fish deep in the saltwater, and by the time they got to the surface, their eyes were bulging, and their swim bladder had expanded so far it was pushing the stomach right out of it's mouth.