Rockfish Barotrauma Information

Blue rockfish with protruding stomach-enlarged photo in new window when selected, Canary rockfish with crystalized, buldging eyes-enlarged photo in new window when selected and Blue rockfish with stomach fully protruding out of its mouth - enlarged photo will open in new window when selected
CDFW Photos

What is Barotrauma?

Barotrauma is a pressure related injury. Rockfish have a specialized gas filled sac that allows them to control buoyancy and maintain depth in the water column. Barotrauma occurs due to a rockfish's inability to release expanding gasses in the swim bladder when it is reeled up and brought to the surface. Barotrauma injuries can cause eyes, stomach or vent to appear to be blown up or greatly expanded. Because swim bladders are designed to function at different depths and pressures depending on the species of rockfish, the severity of barotrauma injuries varies among rockfish.

Schematic of rockfish as they are brought to the surface and then returned to depth. The swim bladder expands with gas when brought up to surface, and is then recompressed when returned to depth. Enlarged image with text will open in new window when selected
Click to enlarge

This graphic depicts what happens to a rockfish when it is brought up from depth.  At depth, the gasses in the swim bladder are at equal pressure. When the fish is reeled up to the surface, the gasses expand and can cause the eyes to become bulged, cloudy or crystallized and the stomach to protrude out of the mouth. Although one might suspect that the fish is dead- it’s not. Rockfish can be re-pressurized, and done so by returning the fish to the depth in which it was caught.


Discarding Fish & Benefits of Proper Release

The most common reason for discarding a live rockfish is due to regulatory requirements such as exceeding a sub-bag or bag limit, or catching a prohibited species. Yet, discarding can also occur when attempting to target other species after meeting the rockfish bag limit, or when the rockfish is smaller or less desirable. Survival of released rockfish is very important as it provides future opportunity for that rockfish to grow and spawn. Survival is increased when the fish is returned to depth as soon as possible. When descending devices are utilized, survival rates are increased. This increase in survival is taken into account when developing  recreational fishing regulations.

Canary rockfish floating at the surface of the water, photo taken from beneath the surface.Flock of Seagulls flying over a bundle of fishing rods on a sport fishing boat.Canary rockfish floating at the surface, with a seagull watching closely nearby.
CDFW Photos

What Not To Do

Venting, Deflating or 'Fizzing' are terms which refer to releasing excess gas within the swim bladder by inserting a hypodermic needle into the swim bladder. Although this is a familiar practice among fishermen (or commonly practiced by fishermen), it is discouraged.

Problems and concerns of Rockfish and Barotrauma

Problems and concerns:

  • Can cause internal damage to the swim bladder and other organs.
  • Can lead to infection
  • Reduces fish’s ability to regulate gas volume leading to changes in behavior after release.

What Every Angler Can Do - Descend and Let Them Grow!

Anglers have options to help return rockfish to depth called descending devices,which can be made at home or purchased commercially.

Homemade Descending Device


Milk Crate, with weights and rope for descending fish-enlarged photo in new window when selected
CDFW Photo

  • Can be constructed from a plastic crate, minimal weight (~5lbs) and at least 60ft of rope.
  • This device is inexpensive, easy to use and multiple fish can be returned to depth at once.
  • Simply place the fish in the crate, swiftly invert the crate into the water and slowly lower to depth.

Commercial Descending Devices


Blue rockfish on a Shelton descending device: enlarged image will open in new window when selected
CDFW Photo

  • The Shelton attaches to lower jaw through the soft membrane with sharp edge pointing down.
  • After lowering the fish back to depth, a jerk of the rod releases the fish.
  • This product can be used on a rod designated just for descending fish, or inline with your fishing gear to easily descend without changing rods.


Roklees Descending Device - enlarged image will open in new window when selected
CDFW Photo

  • The RokLees device attaches to the lower jaw of the fish. With the yellow pad placed under the lower jaw.
  • Using a light weight, the fish can be slowly lowered to depth and with a firm shake of the rod, the clamp will open and the fish will be released.


Blacktip Descending Device - enlarged image will open in new window when selected
CDFW Photo

  • The Blacktip, is a spring loaded jaw clamp.
  • Similar to other commercial devices, the fish is released when the device hits the bottom or is given a swift jerk.


lue rockfish on a Blacktip descending device-enlarged image in new window when selected
CDFW Photo

  • The Seaqualizer attaches to the lower jaw and has a self release mechanism, meaning no need to jerk the rod when you get to the desire depth.
  • This device has a pressure pin built in that allows for automatic release at a depth specific.
  • With three depth options, an angler can choose the depth of release.
  • IMPORTANT: This device is intended to be used on a separate rod not inline with fishing gear. This is not considered a second rod and is legal to use.

Re-compression at Work

China Rockfish with protruding anus due to barotruama-enlarged image in new window when selected
Before: China Rockfish - Depth- 0 ft.
Characteristics: distention of eyes and stomach, protruding vent.

China Rockfish after recompression, protruding anus eliminated-enlarged image in new window when selected
After: China Rockfish - Depth- 35 ft.
Characteristics: Vent returns to natural position.


Before: Canary Rockfish - Depth- 0 ft.
Characteristics- 'Crystallization' of cornea, distention of eye.

After: Canary Rockfish - Depth- 135 ft.
Characteristics- clear cornea, eye recompressed into socket.


If It’s Not A Winner, It's A Descender!

Canary Evidence

China Evidence

Get Hooked On Descending

Barotrauma fish on the hook
CDFW Photo

Science Corner


  • Hannah, R. W., & Matteson, K. M. (2007). Behavior of nine species of Pacific rockfish after hook-and-line capture, recompression, and release. Transactions of the American Fisheries Society, 136(1), 24-33.
  • Hannah, R.W., et. Al. (2011). Use of a novel cage system to measure post recompression survival of northeast pacific rockfish. Marine and Coastal Fisheries, 4(1), 46-56.
  • Hochhalter, S. J., & Reed, D. J. (2011). The effectiveness of deepwater release at improving the survival of discarded yelloweye rockfish. North American Journal of Fisheries Management, 31(5), 852-860.
  • Jarvis, E.T., Lowe, C.G. (2008). The effects of barotrauma on the catch-and-release survival of southern California nearshore and shelf rockfish (Scorpaenidea, sebastes spp.). Canadian Journal of Fisheries and Aquatic Sciences, 65(7), 1286-1296.
  • Parker, S.J., (2006). Buoyancy regulation and barotrauma in two species of nearshore rockfish. Transactions of the American Fisheries Society, 135(5), 1213-1223.
  • Smiley, J.E., Drawbridge, M.A. (2007). Techniques for live capture of deepwater fishes with special emphasis on the design and application of a low-cost hyperbaric chamber. Journal of Fish Biology, 70(3), 867-878.

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Barotrauma Recompression Research