427 
Effects of rapid decompression 
and exposure to bright light on visual function 
in black rockfish ( Sebastes melanops ) 
and Pacific halibut ( Hippog/ossus stenolepis ) 
Richard Brill (contact author ) 1 
Christopher Magel 2 
Michael Davis 3 
Robert Hannah 4 
Polly Rankin 4 
Email address for R. Brill: rbrill@vims.edu 
1 Cooperative Marine Education and Research Program 
Northeast Fisheries Science Center 
National Marine Fisheries Service, NOAA 
Woods Hole, Massachusetts 02543 
2 Virginia Institute of Marine Science 
Gloucester Point, Virginia 23062 
3 Fisheries Behavioral Ecology Program 
Alaska Fisheries Science Center 
National Marine Fisheries Service, NOAA 
Newport, Oregon 97365 
4 Oregon Department of Fish and Wildlife 
Hatfield Marine Science Center 
Newport, Oregon 97365 
Abstract — Demersal fishes hauled up 
from depth experience rapid decom- 
pression. In physoclists, this can 
cause overexpansion of the swim blad- 
der and resultant injuries to multiple 
organs (barotrauma), including severe 
exophthalmia (“pop-eye”). Before 
release, fishes can also be subjected 
to asphyxia and exposure to direct 
sunlight. Little is known, however, 
about possible sensory deficits result- 
ing from the events accompanying 
capture. To address this issue, electro- 
retinography was used to measure the 
changes in retinal light sensitivity, 
flicker fusion frequency, and spectral 
sensitivity in black rockfish ( Sebastes 
melanops ) subjected to rapid decom- 
pression (from 4 atmospheres absolute 
[ATA] to 1 ATA) and Pacific halibut 
(Hippoglossus stenolepis ) exposed to 
15 minutes of simulated sunlight. 
Rapid decompression had no measur- 
able influence on retinal function in 
black rockfish. In contrast, exposure 
to bright light significantly reduced 
retinal light sensitivity of Pacific 
halibut, predominately by affecting 
the photopigment which absorbs the 
green wavelengths of light (=520-580 
nm) most strongly. This detriment is 
likely to have severe consequences 
for postrelease foraging success in 
green-wavelength-dominated coastal 
waters. The visual system of Pacific 
halibut has characteristics typical of 
species adapted to low light environ- 
ments, and these characteristics may 
underlie their vulnerability to injury 
from exposure to bright light. 
Manuscript submitted 28 February 2008. 
Manuscript accepted 23 June 2008. 
Fish. Bull. 106:427-437 (2008). 
The views and opinions expressed 
or implied in this article are those 
of the author and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The effects of events during capture 
and release on postrelease mortality 
have been characterized in a range of 
demersal fish species (e.g., Davis, 2002; 
Parker et ah, 2003; Davis and Parker, 
2004; Davis and Schreck, 2005; St 
John and Syers, 2005; Davis and 
Ottmar, 2006; Davis, 2007; Hannah 
and Matteson, 2007; Rummer, 2007), 
but their impacts on sensory systems 
have not been addressed. Demersal 
fishes are commonly subjected to 
rapid decompression during capture 
in both commercial and recreational 
fisheries. The resultant overexpan- 
sion of the swim bladder in physoclists 
causes injuries to multiple organs 
(barotrauma) including exopthal- 
mia (“pop-eye”) (Parrish and Moffitt, 
1993; Rummer and Bennett, 2005). 
Fishes are also commonly held out 
of the water while being unhooked, 
released from nets or traps, or sorted 
from a trawl (Davis and Olla, 2001). 
During this period they can experience 
severely impaired oxygen exchange 
(asphyxia), as well as temperature 
and light levels above those in their 
depth range. One or more of the fol- 
lowing could, therefore, significantly 
impair visual function: 1) mechanical 
damage to the optic nerve or retina 
resulting from rapid decompression- 
induced exophthalmia (Rogers et al., 
2008); 2) physiological damage to the 
retinal cells resulting from multiple 
embolisms, low blood oxygen levels in 
the choroid rete, avascularity of the 
retina, and the need of a continuous 
supply of oxygen in the retinal cells 
(Fonner et al., 1973; Berenbrink et ah, 
2005) ; 3) permanent bleaching of reti- 
nal cell photopigments or retinal cell 
apoptosis (cell death) due to exposure 
to bright light (Loew, 1976; Wu et ah, 
2006) ; and 4) clouding of the cornea 
or lens (cataract formation) (Midtlyng 
et ah, 1999). Reduced visual function 
could subsequently result in increased 
mortality due to predation (Mesa et 
ah, 1994) or the diminished ability to 
capture prey (Stoner, 2003). 
Black rockfish ( Sebastes melanops ) 
and Pacific halibut ( Hippoglossus 
stenolepis) are good representative 
species for testing the consequences 
