170 
Fishery Bulletin 1 10(2) 
Recreational 
Charter 
Circle 
D Dolphinfish ( Corvphaena hippurus) 
E T unas 
Mackerels 
Circle 
J. . 
m 
Hook type 
Figure 7 
Plots of the average proportion of fish that hooked up (±standard error) on circle hooks 
(open bars) and J hooks (gray bars). Data for plots includes hook-ups from unidentified 
fish later apportioned to species that could be identified. Data for each group are from 
both directed and nondirected trips for that species. Plots are broken down by user group 
(recreational 1 left column, panels A-C] and charter [right column, panels E-F]) and 
taxa (dolphinfish [Coryphaena hippurus] [A, D], tunas [B, E], and mackerels [C, F] ). 
The tuna group included yellowfin tuna ( Thunnus albacares ), blackfin tuna ( Thunnus 
atianticus), skipjack tuna (Euthynnus pelamis), and false albacore (Euthynnus aliet- 
teratus). The mackerel group included wahoo (Acanthocybium solandri), king mackerel 
(Scomberomorus cavalla), and Spanish mackerel ( Scomberomorus maculatus). The legend 
denoting fill pattern for each leader type applies to all panels. No bar for a particular 
hook-type+taxon+user-group+leader-type combination indicates no catch. 
species-hook interactions; main effects for hook type 
remained unbiased. 
If fishermen are interested in releasing dolphinfish, 
our results provide evidence that released fish are not 
hooked as deeply and thus have a higher likelihood of 
survival if circle hooks are used. The drop-back tech- 
nique that we commonly used for dolphinfish likely 
led to a higher percentage of dolphinfish becoming 
deep hooked with J hooks over that for the tuna and 
mackerel taxa groups. The reduction in gut hooking 
with circle hooks has been found in most other stud- 
ies comparing circle and J hooks (Cooke and Suski, 
2004). Managers should factor in the high rate of 
deep hooking for J-hooked dolphinfish as they imple- 
