FISH CAN SURVIVE BAROTRAUMA
Amazingly, rockfish that look dead at the surface can“pop” back to life if quickly returned close to the depth
where they were caught. Because of this, rockfish that you
must toss back should be quickly recompressed.

USE THE FOLLOWINGGEAR AND TECHNIQUESTO SAVE ROCKFISH LIKE THIS!

CDFW file photo

CDFW file photo

Even fish with bulging eyes and protruding stomach can survive ifreturned to depth quickly. Note: the organ protruding from the fish’s
mouth is the stomach, not the swim bladder.

TOP FIVE REASONS TOSEND ‘EM DOWNCDFW / E. Jarvis

There are many ways of returning a fish to a depth atwhich it can recompress. Your choice may depend on thesize of the fish you usually catch, your experience as anangler, sea conditions and cost.

Inverted barbless hook with weight: Hook fish
through lower lip or the membrane on the upper lip
with the barbless, weighted hook and immediately let
out line to allow the fish to sink towards the bottom. Theweight must lead the fish into the water and be heavy
enough to return the fish to the desired depth. Fish arereleased with a sharp jerk on the line. Considerations: Tryto keep the hook from puncturing an extruded stomach,and the line from cutting the eyes during release. Oncethe fish regains muscle coordination, it may wrestle freeprematurely. Method works best with smaller fish.

Why should you care about helping a released fish
return to depth?
1.

Recompressing fish using a descending device canincrease their chances of survival.

2.

Venting fish may cause more harm than good (seenote below).

3.

Descending device usage is accounted for in somefisheries management, and may potentially allow
for greater fishing opportunities in the future.

4.

Some populations of prohibited species, such as
canary and yelloweye rockfish, may take decades
to rebuild.

5.

Floating fish are a waste of the resource.

Catch-and-release practices work best when you
can help with fish survival. Helping fish get backdown is good for the resources and the sport.

CDFW file photo
CDFW / C. Mcknight

Upside-down milk crate, weighted and attached to a rope:
Crate is dropped over the fish and then, with thebuoyant fish inside, lowered to a minimum depth of 60
feet and kept down until it can swim out on its own.
Considerations: In rough seas, fish can escape prematurely
and the crate may bang against a fish’s extended eyes. Trylowering the fish down gently or paint crate’s inside with arubberized coating to smooth sharp edges.

Commercial fish descenders: There are a variety ofpractical, easy-to-use descending devices on the market.
The best one for you may depend on the sizes and species
you catch, as well as the conditions in which they aredeployed. For more information, please visit the California
Department of Fish and Wildlife website at:www.dfg.ca.gov/marine/groundfishcentral/barotrauma.asp

VENTING: A sharp needle or steel cannula is used to puncture a fish’s inflated swim bladder.

The California Department of Fish and Wildlife does not currently encourage venting as it can cause
serious injury to fish and angler. You may accidentally puncture the wrong organ and/or introduce
infection. Even when done properly, venting damages a fish’s swim bladder.

WHY ARE ROCKFISH PRONE TO
PRESSURE-RELATED INJURIES?
Every rockfish has a gas-filled organ called a swim
bladder that allows the fish to gently control itsbuoyancy. By deflating its bladder, a fish can descend
more easily. By inflating it, its ascent is assisted. When afish is caught and reeled in, this mechanism for moving
vertically in the water column is thrown out of whack.
Depending on the depth at which the fish was caught, afish’s swim bladder may swell so much its stomach is forcedout its mouth. The eyes may bulge and other organs canbe injured as well. Fish suffering from pressure-related
injuries are said to be experiencing barotrauma (pressureshock). Without intervention, a fish with barotrauma
may die from the progression of its wounds or succumb
to temperature shock or predators.
“Floaters” – overly inflated fish that cannot descend
on their own – are especially easy targets for gulls andsea lions.

ROCKFISH-BAROTRAUMA MYTHS
Myth: Reeling a fish in slowly prevents barotrauma.
Fact: Rockfish cannot acclimate to the pressure drop
even when reeled in slowly.
Myth: The organ protruding from a “popped” fish’s
mouth is the swim bladder.
Fact: It is the stomach! Never vent the stomach or try
to force it back inside the mouth.
Myth: You can tell by looking whether a fish willsurvive or die.
Fact: When properly recompressed, even fish withsevere barotrauma can survive.

ROCKFISH-BAROTRAUMASCIENCE
According to published results of a Sea Grant
study led by researchers at Cal State Long Beach:
The degree of barotrauma in a fish is not a reliablepredictor of its survival. The most significant
predictor of post-release survivorship is the time afish spends at the surface.
In experiments with several species of common
Southern California rockfish, 83 percent of fishcaught at depths between 217 feet and 350 feet,survived when returned to depth within 2 minutes.
The odds of a fish dying following recompression
nearly doubled with every 10-minute increase in timeat the surface.

illustration courtesy of California Sea Grant

The volume of a fish’s swim bladder will triple when reeled in fromdepths as shallow as 66 feet.

Alternate communication formats of this document are available
upon request. If reasonable accomodation is needed, call CDFW at(707) 964-5026. The California Relay Service for the deaf or hearing
impaired can be utilized from TDD phones at (800) 735-2929.
V2 - 01/31/2014M.Patyten

Tagging and recapture studies showed some releasedfish were still alive 1.5 years later.
For current recreational groundfish fishing regulations,call (831) 649-2801 for recorded information or visit theCalifornia Department of Fish and Wildlife website atwww.dfg.ca.gov/regulations.asp.

This brochure was a collaborative effort of California Sea Grant, Oregon Sea Grant
and University of Southern California Sea Grant. Production and printing of thisupdated version were funded by the California Department of Fish and Wildlife.

CDFW / M. Parker

BRING THATROCKFISHDOWN