This week, I ‘ll describe the deepwater-release technique developed for rockfish. In my last post, I wrote about rockfish conservation and talked about ways anglers can help preserve vulnerable rockfish populations. Due to their unvented swim bladder, rockfish are extremely sensitive to changes in water pressure. When an angler catches a rockfish in water deeper than 90 ft. (27.43 m) and reels it to the surface, the fish’s swim bladder rapidly expands, compressing internal organs and often pushing the stomach out through the mouth. These pressure change can also rupture blood vessels, tear the swim bladder, and cause bulging eyes or gas bubbles in the eyes.
Sometimes rapid pressure changes cause physiological damage so severe it kills the fish, but in other instances, the fish can survive if the angler quickly returns it to the depth where it was caught.
Since a rockfish’s swim bladder rarely deflates on its own once the fish arrives at the surface, the fish cannot dive and instead floats until it dies or is eaten. Anglers sometimes mistakenly feel they can help the fish by either puncturing the stomach protruding from the fish’s mouth or puncturing the fish’s body to let air out of the swim bladder. This technique, called “fizzing” or “venting,” often leads to infection and eventual death.
Recently, biologists have developed a new deepwater-release technique to submerge rockfish as quickly as possible either to the depth where they were caught or 100 feet (30.5 m), whichever comes first. Research on this technique has shown a substantial increase in the survival of released rockfish. One laboratory study produced a survival rate of 96% for recompressed rockfish. Another study in the wild found only 22% of yelloweye rockfish released at the water’s surface managed to submerge, but 98% of yelloweyes survived when submerged to the depth where they were captured.
The Alaska Department of Fish and Game has now added the deepwater-release technique to its list of “best practices” for anglers to employ to minimize release mortality of rockfish. Biologists believe if they can convince anglers to use this technique, as well as follow other rockfish conservation methods, rockfish mortality will decrease significantly.
What is the deepwater-release technique? It is a simple procedure, but since time is critical, rockfish anglers should have the gear ready and be prepared to implement the technique as soon as the rockfish arrives at the surface.
Several deepwater-release devices, from simple to sophisticated, can be purchased, but you can also easily make your own deepwater-release device. Begin with a 3-lb. jig with a single hook and grind the barb off the hook. Next, take a fishing rod and attach the line to the bend of the hook. Assemble the device and have it ready to go before you start fishing. The fish is much more likely to survive if you minimize its time at the surface, so have the device assembled and make sure you know what to do before you catch a rockfish.
If you think you have a rockfish on the line, quickly reel the fish to the surface. The swim bladder will inflate regardless of your reeling speed. Remove the hook from the fish’s mouth and attach the release device. If using a homemade device, hook the barbless hook through the soft tissue of the jaw. Gently drop the fish back into the water and release the anti-reverse on the reel, allowing the line to free spool. Allow the fish to descend until either the jig hits bottom, or reaches 100 ft., whichever comes first. Then, give the rod a hard tug to release the fish. The faster you can perform this technique, the more likely the rockfish will survive.
Next week, I’ll discuss marine reserves as a possible management option to protect rockfish populations. Reserves are controversial because both sport and commercial fishing are prohibited in reserves, and many biologists question if reserves work as a form of conservation.
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Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
