Rudershausen et al.: A comparison between circle hook and J hook performance in the troll fisheries off North Carolina 
157 
Stream waters off of North Carolina. Catch composi- 
tion of dolphinfish, yellowfin tuna, and wahoo in this 
troll fishery varies widely among vessels, seasons, and 
locations in the Gulf Stream. 
There is concern in the charter boat industry that 
circle hook regulations (developed for and based on bill- 
fish), if ever mandated outside of U.S. Atlantic billfish 
tournaments, would negatively impact catch rates of 
dolphinfish, yellowfin tuna, and wahoo. Chartering an 
offshore fishing trip in the southeastern United States 
is an expensive endeavor (~$2000/day; senior author, 
personal observ. ) and reductions in catch may have eco- 
nomic influences on charter fishing businesses. Success 
of the offshore troll fishery relies on clientele having 
a reasonable chance to catch and keep fish that are 
highly valued as seafood. In North Carolina, there are 
few charter captains willing to use or experiment with 
circle hooks when targeting non-billfish species because 
there is a widespread perception that trolling circle 
hooks for non-billfish species results in reduced catch 
rates, and therefore greater chances for customer dis- 
satisfaction, compared with J hooks. The charter ocean 
fishing industry in North Carolina includes roughly 
750 vessels and receives $65 million annually in for- 
hire fees (Dumas et ah, 2009). Economic ramifications 
of requiring circle hooks outside U.S. Atlantic billfish 
tournaments have not been quantified. 
Our purpose in undertaking this study was to deter- 
mine the effects of using circle hooks on catch levels of 
non-billfish species in the U.S. southeastern offshore 
troll fishery in comparison with catch levels with J 
hooks. Mechanisms that might explain differences or 
similarities in catch between hook types were also ex- 
amined. Questions were the following: 1) Did predators 
strike circle and J hook rigged baits at similar rates?; 
2) Once struck, did circle and J hook rigged baits have 
similar proportions of hook-ups?; and 3) Once hooked 
up, did circle and J hook rigged baits have similar pro- 
portions of retained fish (brought to the boat)? 
Materials and methods 
Fishing techniques workshop 
In November 2007 we convened a workshop attended by 
state and federal biologists, fishery managers, charter 
boat captains and mates, private boat anglers, and bill- 
fish tournament directors. The purpose of the workshop 
was to select hook types, hook styles, rigging techniques, 
and fishing techniques (see below) that could be used 
to compare trolled circle and J hooks in Gulf Stream 
waters off North Carolina during troll fishing days 
aboard charter vessels. 
Defining and selecting circle and J hooks was a cen- 
tral part of the workshop. A circle hook was defined as 
having the point perpendicular to the hook shank. A J 
hook was defined as having the point and point shank 
parallel to the hook shank. We selected circle and J 
hooks that would be comparable in bend diameter (gap 
between hook shank and point shank). For both hook 
types, we selected barbed hooks with zero offset and 
straight hook eyes (eye parallel to the hook shank). 
The circular shape, hook point turned perpendicularly 
toward the shank, and zero offset insured that the 
circle hooks we selected conformed to the National Ma- 
rine Fisheries Service definition in the current billfish 
tournament regulations (Federal Register, 2006). Other 
hook characteristics (hook size, hook gauge, gap width, 
and shape) were selected to avoid compromising the 
action and durability of the trolled dead whole fish (bal- 
lyhoo [Hemiramphus brasiliensis]). Participants decided 
that circle and J hooks with a gap width large enough 
that allowed space between the bait and hook for hook- 
ing fish but with a relatively low profile (by virtue of 
the gauge of hook wire) would be most appropriate for 
testing. 
Bait rigging and fishing techniques 
The bait rigging techniques for each non-billfish species 
presented at the workshop were those used by the local 
charter industry. Circle and J hooks were embedded in 
ballyhoo except for directed trips for dolphinfish, when 
circle hooks were rigged externally (Fig. 1). Other dif- 
ferences in bait rigging and fishing techniques are 
described below by species. Flook sizes and styles, leader 
characteristics, and rigging techniques differed slightly 
on recreational trips because these fishermen often troll 
with smaller hooks and different rigging techniques 
from those used by charter captains. 
For charter and recreational trips targeting dolphin- 
fish we used Mustad 9175 7/0 J hooks (Mustad, Gjovik, 
Norway 1 ) that were rigged inside ballyhoo; the chin 
weight was affixed to 30 cm of rigging wire. We used 
Eagle Claw 2004ELG 8/0 circle hooks (Eagle Claw 
Fishing Tackle Co, Denver, CO) rigged externally to 
the ballyhoo with a 7-g chin weight and swivel at the 
top of the head, with 30-cm of rigging wire (no pin). 
The leader was 1.8 m of 36 kg of monofilament attached 
to the standing line with a 31-kg Sampo ball-bearing 
swivel (Sampo Inc., Barneveld, NY). The leader was 
attached to the hook by using a loose crimp with tag 
end opposite the point (Fig. 1A). We used lever drag 
reels affixed to “thirty pound-class” stand-up rods at 
all locations. Reels were spooled with a 14-kg test Dia- 
mond® monofilament line (Diamond Fishing Products, 
Pompano Beach, FL). The drag upon strike of a fish 
was set just above “free spool” (reel gear not engaged) 
with the clicker in the “on” position. The drag during 
the fight of a fish (regardless of species) was roughly 
6.4 kg. Baits were dropped back (line allowed to come 
off the spool with no drag) to missed fish (that struck) 
immediately after the strike. Recreational rigging tech- 
niques for dolphinfish were similar to those used on the 
1 Mention of trade names or commercial companies is for 
identification purposes only and does not imply endorsement 
by the National Marine Fisheries Service, NOAA. 
