But for me, the problem doesn’t become extreme until we reach 28 to 30 feet. Still, we know that the fish at greatest risk in our region are the ones who inhabit water that is greater than 20 feet deep.Īnecdotally, I have seen evidence of mild barotrauma in fish that I’ve caught as shallow as 24 feet deep. But there is no one magic depth at which it occurs and it can even happen to certain fish in shallow water. Generally, the deeper the fish are living, the greater the risk of decompression becomes. In fact, one study documented over 70 injuries that could arise from severe decompression.” In it, they reported “Beyond problems with swim bladder distention (which, in some species, includes stomach or anal eversion or swim bladder bursting, fish that are exposed to decompression can experience internal damage to peritoneum, kidneys, dorsal aorta and external damage to fins, gums, body surface, hemorrhaging ocular pressure formation of gas bubbles within the circulatory system, gills, heart and brain. Cooke, the study focused on a Smallmouth Bass fishing tournament conducted at Rainy Lake. Conducted by Marie-Ange Gravel and Steven J. But later, internal injury to the fish catches up to it and it dies.įisheries Biologist Jeff Reed, MN DNR hooked me up with a study published by the North American Journal of Fisheries Management in 2008. In cases like that, an angler may release a fish believing that it will be fine. The problem is that there are instances when damage to the fish is far less noticeable and wouldn’t easily be detected by the naked eye. Most folks recognize when a fish has a severe case of it because the swim bladder could come pushing out of its throat or maybe because its eyes are bulging out of the sockets, in cases like that the problem is pretty obvious. As they expand, injuries occur, minor ones at first, but if the cells expand too much, the injuries can be fatal. As the fish is reeled in from the depths, the pressure decreases and those living cells begin to expand. The pressure that surrounds a fish in deep water has the affect of packing all of it's vital organs tightly. It’s a process called decompression and it occurs when any living thing undergoes a rapid transition from an environment of high ambient pressure relative to one where the ambient pressure is lower.
It can be a big problem, especially when the fish are hungry and the angler believes that they're fishing for sport or when they’re “high-grading”, the practice of being super selective about which fish they harvest and which ones they won't.īoth of those practices can lead to the untimely demise of many fish and often times’ number far greater than the angler ever intended or expected to harvest. In fact you could say that catching fish in deep water isn’t a problem at all.īut releasing fish that are reeled in from the depths is a whole new ballgame. As long as we capture what we need put ‘em in the cooler and head home for the fish fry, it doesn’t matter whether we catch them shallow or deep. Panfish move into deep water and anglers, including me, move out there to catch them.įor many, gathering fish for a meal is the primary goal and when it is, catching them in deep water really isn’t a problem. It happens every fall and winter in my neck of the woods. How Barotrauma Affects Released Fish - What We Don’t Know Might Kill Them - Jeff Sundin October 2019