433 
Abstract — We evaluated the conser- 
vation benefits of the use of circle 
hooks compared with standard J 
hooks in the recreational fishery for 
Atlantic istiophorid billfishes, noting 
hooking location and the presence of 
trauma (bleeding) for 123 blue marlin 
(Makaira nigricans ), 272 white marlin 
(Kajikia albida), and 132 sailfish 
(Istiophorus platypterus ) caught on 
natural baits rigged with one of the 
two hook types. In addition, we used 
pop-up satellite archival tags (PSATs) 
to follow the fate of 61 blue marlin 
caught on natural baits rigged with 
circle hooks or on a combination of 
artificial lure and natural bait rigged 
with J hooks. The frequencies of inter- 
nal hooking locations and bleeding 
were significantly lower with circle 
hooks than with J hooks for each of 
the three species and were signifi- 
cantly reduced for blue marlin caught 
on J hooks than for white marlin 
and sailfish taken on the same hook 
type. Analysis of the data received 
from 59 PSATs (two tags released 
prematurely) indicated no mortali- 
ties among the 29 blue marlin caught 
on circle hooks and two mortalities 
among the 30 blue marlin caught on 
J hooks (6.7%). Collectively, the hook 
location and PSAT data revealed that 
blue marlin, like white marlin and 
sailfish, derive substantial conserva- 
tion benefits from the use of circle 
hooks, and the negative impacts of 
J hooks are significantly reduced for 
blue marlin relative to the other two 
species. 
Manuscript submitted 6 April 2010. 
Manuscript accepted 22 July 2010. 
Fish. Bull. 108:433-441 (2010). 
The views and opinions expressed 
or implied in this article are those 
of the author (or authors) and do not 
necessarily reflect the position 
of the National Marine Fisheries 
Service, NOAA. 
Asymmetric conservation benefits of circle hooks 
in multispecies hillfish recreational fisheries: 
a synthesis of hook performance and analysis 
of blue marlin ( Makaira nigricans ) 
postrelease survival 
John E. Graves (contact author ) 1 
Andrij Z. Horodysky 2 
Email address for contact author: graves@vims.edu 
1 Department of Fisheries Science 
Virginia Institute of Marine Science 
College of William & Mary 
Rt. 1208 Greate Road 
Gloucester Point, Virginia 23062 
2 Living Marine Resources Cooperative Science Center 
Department of Marine and Environmental Science 
Hampton University 
100 E. Queen St. 
Hampton, Virginia 23668 
Istiophorid billfishes in the Atlantic 
Ocean experience considerable fish- 
ing pressure and most stocks are 
overfished. The greatest source of 
fishing-induced mortality for istio- 
phorids results from the pelagic long- 
line fishery that targets tunas and 
swordfish; however, artisanal and rec- 
reational fisheries also represent sig- 
nificant sources of mortality for some 
species (Arocha and Ortiz, 2006). 
The United States National Marine 
Fisheries Service (NMFS) man- 
ages the recreational hillfish fishery 
with relatively large minimum sizes 
released to ensure that the major- 
ity of billfishes are released: 251 cm 
(99 in) lower jaw fork length (LJFL) 
for blue marlin (Makaira nigricans), 
168 cm (66 in) LJFL for white marlin 
(Kajikia albida ), and 152 cm (60 in) 
LJFL for sailfish (Istiophorus platyp- 
terus). No recreational landings are 
allowed for longbill spearfish (Tet- 
rapturus pfluegeri), and no manage- 
ment measures currently exist for 
roundscale spearfish (T. georgii). As 
a result of these management mea- 
sures and changes in angler behavior 
promoting live release of these species 
(Ditton and Stoll, 2003), the U.S. rec- 
reational hillfish fisheries are primar- 
ily catch-and-release fisheries, and up 
to 99% of white marlin are released 
alive annually (Goodyear and Prince, 
2003). However, not all billfishes that 
are released alive survive capture; 
postrelease mortality can be signifi- 
cant in some fisheries (Domeier et ah, 
2003; Horodysky and Graves, 2005). 
A growing body of evidence indi- 
cates that the use of circle hooks can 
greatly reduce the incidences of in- 
ternal (deep) hooking, hook induced 
trauma (bleeding), and postrelease 
mortality of piscivorous fishes (Mu- 
oneke and Childress, 1994; Skomal 
et al., 2002; Cooke and Suski, 2004), 
including billfishes (see Serafy et ah, 
2009). For istiophorid billfishes, live 
and dead natural baits rigged with J 
hooks reveal higher frequencies of in- 
ternal hooking locations and trauma 
for sailfish, striped marlin (K. audax), 
and white marlin than the same baits 
rigged with circle hooks (Prince et 
al., 2002, 2007; Domeier et al., 2003; 
Horodysky and Graves, 2005). Using 
pop-up satellite archival tags (PSATs) 
to follow the fate of released fish, Do- 
meier et al. (2003) noted a reduced 
but nonsignificant postrelease mortal- 
ity for striped marlin caught on live 
natural baits rigged on circle hooks, 
and Horodysky and Graves (2005) re- 
ported a highly significant reduction 
