156 
A comparison between circle hook 
and J hook performance in the dolphinfish, 
yellowfish tuna, and wahoo troll fishery 
off the coast of North Carolina 
Abstract — We compared numbers of 
strikes, proportions of fish that hooked 
up after strikes, proportions of fish 
that stayed on hook (retained) after 
hook up, and numbers of fish caught 
between circle and J hooks rigged 
with dead natural fish bait (ballyhoo) 
and trolled for three oceanic preda- 
tor species: dolphinfish iCoryphaena 
hippurus), yellowfin tuna (Thunnus 
albacares), and wahoo ( Acanthocybium 
solandri ). Interactions were compared 
between circle and J hooks fished on 
75 trips by two user groups (charter 
and recreational fishermen). Hooks 
were affixed to three species-specific 
leader types most commonly fished 
in this region: monofilament (dol- 
phinfish), fluorocarbon (tuna), and 
wire (wahoo). Numbers of fish caught 
per trip and three potential mecha- 
nisms that might influence numbers 
caught ( i.e. , number of strikes, propor- 
tion of fish hooked, and proportion 
retained) were modeled with gener- 
alized linear models that considered 
hook type, leader type, species, user 
(fishing) group, and wave height as 
main effects. Hook type was a main 
effect at the catch level; generally, 
more fish were caught on J hooks 
than on circle hooks. The effect of 
hook type on strike rates was equivo- 
cal. However, J hooks had a greater 
proportion of hook-ups than did circle 
hooks. Finally, the proportion of fish 
retained once hooked was generally 
equal between hook types. We found 
similar results when data from addi- 
tional species were pooled as a “tuna” 
group and a “mackerel” group. We 
conclude that J hooks are more effec- 
tive than circle hooks at the hook-up 
level and result in greater numbers of 
troll-caught dolphinfish, tunas, and 
mackerels. 
Manuscript submitted 24 May 2011. 
Manuscript accepted 24 October 2011. 
Fish. Bull. 110:156-175 (2012). 
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. 
Paul J. Rudershausen (contact author ) 1 
Literature on a variety of species and 
fishing strategies provides evidence 
that catch rates with circle hooks 
can be maintained (but rates of deep 
hooking are reduced) when compared 
with catch rates with conventional J 
hooks (Cooke and Suski, 2004). Stud- 
ies on the relative effectiveness of 
hook types for billfishes have revealed 
that circle hooks offer a conservation 
benefit (reduced rates of deep hooking) 
while maintaining catch rates compa- 
rable to those with J hooks for both 
troll and longline fisheries (Serafy 
et ah, 2009). For example, Prince et 
al. (2002) found that trolled circle 
hooks rigged with natural baits main- 
tained catch rates of Atlantic sailfish 
( Istiophorus platypterus ) but reduced 
rates of deep hooking compared with 
catch rates with J hooks. Similarly, 
Horodysky and Graves (2005) found 
that white marlin ( Kajikia albida) 
caught on trolled circle hooks had no 
mortality compared to 35% mortality 
on J hooks. Based on these findings, 
a rule was instituted by the National 
Marine Fisheries Service (NMFS) 
that required the use of non-offset 
circle hooks when trolling natural or 
combination baits (natural bait and 
skirt) in Atlantic billfish tournaments 
(Federal Register, 2006). The intent 
Randy W. Gregory 3 
Tyler W. Averett 1 
Paul B. Conn 4 5 
3 North Carolina Division of Marine Fisheries 
3441 Arendell Street 
Morehead City, North Carolina 28557 
4 National Marine Fisheries Service 
Southeast Fisheries Science Center 
101 Pivers Island Road 
Beaufort, North Carolina 28516 
5 National Marine Fisheries Service, NOAA 
National Marine Mammal Laboratory 
Alaska Fisheries Science Center 
7600 Sand Point Way NE 
Seattle, Washington 98115-6349 
of this regulation was to reduce deep 
hooking, and thus rates of catch-and- 
release mortality, in white and blue 
marlin ( Makaira nigricans). 
Outside of directed tournaments, 
Atlantic billfishes are generally not 
the only targets in charter and recre- 
ational troll fishery of North Caroli- 
na. For many ports, billfishes are on- 
ly a rare bycatch. In North Carolina, 
dolphinfish ( Coryphaena hippurus), 
yellowfin tuna (Thunnus albacares), 
and wahoo (Acanthocybium solandri) 
are the predominant targets of rec- 
reational and charter trip troll fish- 
eries in Gulf Stream waters (senior 
author, personal observ.). Dolphin- 
fish and yellowfin tuna are the top 
two species by weight landed in the 
North Carolina recreational fishery 
and together represent over half of 
the total recreational landings in the 
state (NCDMF, 2010). Recreational 
and charter anglers harvest 93% of 
the roughly 4.5 million kg of dolphin- 
fish landed annually along the U.S. 
Atlantic coast and roughly 90% of wa- 
hoo landed in U.S. South Atlantic wa- 
ters (North Carolina through Florida) 
and Mid-Atlantic waters (New York 
through Virginia) (SAFMC, 2003). 
Trolling is the predominant fishing 
method for pelagic fishes in Gulf 
Jeffrey A. Buckel 1 
Greg E. Bolton 2 
Email address for contact author: piruders(a>ncsuedu 
1 Department of Biology 
Center for Marine Science and Technology 
North Carolina State University 
303 College Circle 
Morehead City, North Carolina 28557 
2 North Carolina State University 
Department of Food, Bioprocessing, 
and Nutrition Sciences 
Center for Marine Science and Technology 
303 College Circle 
Morehead City, North Carolina 28557 
