486 
Fishery Bulletin 115(4) 
Figure 1 
Photograph and location of the intake canal of the Florida Power and Light 
St. Lucie Nuclear Power Plant on Hutchinson Island, where nurse sharks 
(Ginglymostoma cirratum) were captured with the poker-and-hook tool and 
monitored to evaluate this new underwater method for catching sharks. 
vent the deployment of gill nets and can easily sever 
fishing lines. 
Equipment and capture technique 
The poker-and-hook tool consisted of a long shanked 
stainless-steel J-hook (size 10/0 with its barb removed) 
attached to an 80-cm twine leader (90-kg test), a 20 nr,, 
rope and retrieval buoy, and a 90-cm metal rod (the 
poker) (Fig. 2A). We wrapped the twine leader 2-3 
times around the poker to avoid entanglement under¬ 
water (Fig. 2B). The steel hook was fastened to the 
poker with 2-mm cable ties: 2 cable ties were threaded 
through a hole at the end of the poker and through the 
eye of the hook, and a third cable tie cinched the hook 
towards the tip (Fig. 20. We also flattened the back 
of the hook and the tip of the poker for added stabil¬ 
ity, and lightly scored the cable ties to facilitate their 
breaking under pressure. 
To capture a nurse shark, a diver descended to 
the targeted individual with the poker-and-hook tool 
in hand, keeping the twine leader taut (Fig. 2B) and 
hooked the side of the caudal peduncle (region between 
the anal and tail fins); hereafter, referred to as the tail 
base (Fig. 3). The diver aimed to hook the upper- or 
lower-lateral part of the nurse shark’s tail base because 
the species is primarily a nocturnal feeder and there¬ 
fore frequently dependent on its lateral line for feed¬ 
ing. Moreover, the skin of the upper and lower parts of 
the tail base in sharks is often thicker and adjoining 
muscle below the skin is also less vascularized than 
that of the middle-lateral part (Shadwick and Goldbo- 
gen, 2012). Once the tail base was 
hooked, the cable ties broke or slid 
off as a result of the shark swim¬ 
ming away with the hook (with the 
poker remaining in hand) and the 
line, now attached to the shark, 
was released. A short video dem¬ 
onstrating this underwater capture 
technique is available (video). 
We then used a 4-m boat with 
low sides (i.e., modified gunnels) 
and pulled in the line by hand un¬ 
til the shark’s tail could be used 
to haul the individual onboard. 
For large sharks (>7Q kg), we las¬ 
soed the shark’s tail at the water 
surface to facilitate hauling these 
heavier individuals into the boat. 
None of the nurse sharks we hauled 
into the boat exhibited any stress- 
induced vertebral ‘popping’ (dislo¬ 
cation of vertebrae) that can occur 
when lifting large fish by their tail 
(e.g., Pacific halibut [Hippoglossus 
stenolepis], senior author, personal 
observ.). Once onboard, the shark 
was restrained by hand and our 
total handling and processing time 
was under 5 min. This period included the time to dock 
the boat and to move the individual with a wet push 
cart to a weigh station, to a holding tank, or to the 
beach for release (see next section). 
Postcapture monitoring and wound assessment 
A total of 20 nurse sharks were captured and released 
between 8 August and 23 October 2014. At first, 4 
sharks were removed from the canal by using this new 
technique. These nurse sharks ranged from 48.9 to 
79.6 kg and experienced hook wounds that were rela¬ 
tively superficial (i.e., shallow punctures with no bleed¬ 
ing). After each individual was examined, we recorded 
weight, maximum total length, and took photos of hook 
wounds to scale. All the sharks were released back into 
the ocean without issue. 
We then proceeded to capture 16 more sharks ranging 
from 11.8 to 80.3 kg, but this time we assessed hook 
wounds in a more systematic way. When sharks were 
hauled into the boat, we first measured hook penetration 
if the hook did not fall out, which was often the case. 
Hook penetration or depth was reported as the straight 
distance between the tip of the hook to the first visible 
part of the hook shank at the surface of the shark’s 
skin. Of these 16 sharks captured, we released 6 nurse 
sharks ranging from 11.8 to 43.8 kg back into the canal 
and 3 sharks ranging from 14.9 to 21.2 kg were put into 
a nearby 3-m diameter open flow-through tank (~0.5 
L/s) in the shade. All sharks >48.9 kg were returned to 
the ocean to reduce handling large individuals a second 
time, and these returned sharks included 2 iedividu- 
