No one releases a fish with the hope it will die. If you want it to die there are plenty of ways to kill it with more certainty than gently slipping it back into the water. But don’t fool yourself if you think catch and release doesn’t kill some fish. It always does.

Whether you are catching tiny brook trout and releasing them back to their shady stream or mighty tarpon, never even pulled from the water some C&R fish – hopefully, only a tiny percentage – but some of them, are so stressed, or perhaps bleeding, or have so much lactic acid built up in their muscles, they’ll never recover.

Here in the Great Lakes there are two culprits working against successful catch and release of fish caught from deep water. Fisheries biologists call them thermal-stress and barotrauma.

Thermal stress occurs when a fish is pulled from the cool depths into the warm water near surface faster than it can adjust internally.

Catching a fish swimming deep in the water column results in barotrauma, caused by the rapid change of water pressure. All Great Lakes fish have swim bladders filled with oxygen. When reeled up from the depths, this bladder expands larger and larger.
I’ve seen perch caught 60 feet deep with their stomach pushed out of their mouth by an over-inflated swim bladder. I’ve seen lake trout caught from 100 feet deep come unhooked just as they are pulled near the surface only to bob up to the top like a balloon. I’ve seen lake trout, caught and released, bob on the surface like a balloon and have found cohos, kings and steelhead in similar straits.

Most of these “floaters” are no more than seagull fodder. To better ensure C&R survival, the swim bladder has to be deflated using one of two methods. Popping the bladder, or “fizzing” the fish with a hollow needle can let out the excess air but unless its done correctly, fizzing is usually fatal.

Several devices have been invented to lower these fish back down into the depths and free them in cooler water deep enough to recompress the fish’s air bladder. The best tool I’ve ever seen to do this is the Seaqualizer.

It’s basically a miniature boca-grip style device which will clamp onto a fish’s jaw. Unlike a boca, which uses a trigger to release, the Seaqualizer has a pressure activated release mechanism. The one I got – the “Striper” model can be adjusted so the jaws trigger open at 30, 50 or 70 feet.

Here’s how I use it when I catch a laker (or shaker salmon) I want to release. I’ve connected the Seaqualizer to a four-foot cord with a stout snap on the end. The snap connects to a downrigger weight or release. The Seaqualizer is clamped to the fish’s jaw, then the fish is dropped into the water and I hit the down switch on the ‘rigger. I lower the weight down to 35, 55 or 75 feet (depending on how the Seaqualizer is set) then bring the weight back to the top. The Seaqualizer is open, the fish is released.

Do the trout, salmon or other fish released this way survive? I can’t answer that. But I bet more of them do than the ones bobbing on the surface as I troll into the distance.


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