Originally published October 5, 2013. Updated October 2026.
Rockfish caught in deep water can suffer from barotrauma as they are brought toward the surface. As water pressure decreases, gas in the swim bladder expands. The fish may become extremely buoyant and unable to swim back down on its own.
A descending device solves this problem by taking the fish back down through the water column. As pressure increases with depth, the expanded gases recompress and the effects of barotrauma can begin to reverse. Returning rockfish quickly to a similar depth from which they were caught with a descending device can greatly improve their chance of survival.
In B.C., using a descending device is not simply a recommended conservation practice. It is a condition of licence when recreational anglers release rockfish from a vessel: rockfish that are not being retained must be immediately returned to the water and to a similar depth from which they were caught using an inverted weighted barbless hook or another purpose-built descending device.
How Descending Devices Help Rockfish
A descending device overcomes the fish’s buoyancy and carries it back down through the water column. As pressure increases with depth, the expanded gases recompress. Common designs include pressure-release clamps, manually triggered clamps and inverted weighted barbless hooks.
How to Release a Rockfish with a Descending Device
Have a descending device rigged and ready before you start fishing. If a rockfish needs to be released, minimize handling and the time it spends at the surface. DFO recommends lowering unintended rockfish catch in under two minutes and limiting handling to protect the fish’s slime coat. Attach the fish securely to the device according to its design and lower it promptly to a similar depth from which it was caught. Release the fish using the method appropriate for your device.
If you’re unsure which species you’ve caught, see the FishinBC.COM post on Rockfish Identification. Rockfish are also commonly encountered while fishing for other species along the B.C. coast; see the FishinBC.COM Complete Guide to Halibut Fishing, Complete Guide to Lingcod Fishing, and Complete Guide to Salmon Fishing.
Rockfish Bycatch and Descending Devices
Rockfish are commonly encountered while fishing around rocky bottom for halibut, lingcod and other species. If you begin catching rockfish that you do not intend or are not permitted to retain, moving away from the school or changing fishing depth can help reduce additional rockfish bycatch.
Before fishing, know the location of Rockfish Conservation Areas along your route and around the places you intend to fish. Recreational groundfish angling is prohibited in RCAs, along with several other recreational fishing methods. Check the current DFO Rockfish Conservation Area regulations and boundaries before fishing.
Venting Is Not an Alternative to a Descending Device in B.C.
Venting—puncturing a rockfish to release expanded gas from its body—is sometimes discussed as a way of dealing with barotrauma. Venting is not an appropriate alternative for releasing rockfish in British Columbia.
B.C. recreational fishing regulations require anglers to use a descending device when releasing rockfish. The fish should be returned to a similar depth from which it was caught using an inverted weighted barbless hook or another purpose-built descending device rather than vented and released at the surface. See the current DFO recreational finfish regulations before fishing.
A descending device allows increasing water pressure to recompress the fish naturally as it is lowered. There is no need to puncture the fish when the required release method is to return it to depth.
Rockfish Release Videos
These three videos provide useful examples of rockfish release, descending devices and rockfish behaviour. The first, produced by the Alaska Department of Fish and Game, demonstrates several types of rockfish release devices.
The second video takes a lighter approach at first, but develops into a useful explanation of barotrauma, recompression and rockfish release for anglers of all ages.
The last video is a short underwater look at a school of rockfish around rocky habitat and suspended in the water column. Seeing how these fish concentrate around structure helps explain why rockfish populations can be vulnerable to fishing pressure and why careful release of fish that are not being retained matters.
Your Turn: What Rockfish Descending Device Do You Use?
What type of descending device do you carry when fishing for rockfish? If you have a particular device or release technique that works well on your boat, let us know in the comments below.
If you have a question about releasing rockfish or using a descending device, leave that below too. Sharing what works on the water can help other anglers safely release rockfish that need to go back.
Tight Lines…FishinBC.COM!