294 
Fishery Bulletin 1 12(4) 
Table 4 
Predicted estimates of release mortality from a meta-analytical model of red snapper ( Lutjanus 
campechanus) in the Gulf of Mexico, by depth (0-100 m), for the average model run (Average) 
of equally weighted coefficients, season (winter, spring, summer, and fall), and fishing sector 
(Comm. commercial and Rec.=recreational). Predicted estimates were derived with the coefficients 
presented in Table 2 and shown in graph format in Figures 3-6). 
Depth 
Average 
Winter 
Spring 
Fall 
Summer 
Annual 
Comm. 
Rec. 
0 
0.199 
0.131 
0.159 
0.225 
0.289 
0.220 
0.437 
0.074 
5 
0.216 
0.144 
0.173 
0.244 
0.311 
0.239 
0.463 
0.081 
10 
0.235 
0.157 
0.189 
0.264 
0.334 
0.258 
0.489 
0.089 
15 
0.254 
0.171 
0.205 
0.285 
0.358 
0.278 
0.515 
0.098 
20 
0.274 
0.187 
0.223 
0.306 
0.382 
0.300 
0.541 
0.108 
25 
0.295 
0.203 
0.241 
0.329 
0.407 
0.322 
0.567 
0.118 
30 
0.318 
0.221 
0.261 
0.352 
0.432 
0.345 
0.592 
0.130 
35 
0.341 
0.239 
0.281 
0.377 
0.458 
0.369 
0.617 
0.142 
40 
0.364 
0.258 
0.303 
0.401 
0.484 
0.394 
0.642 
0.155 
45 
0.389 
0.279 
0.325 
0.427 
0.510 
0.419 
0.665 
0.169 
50 
0.414 
0.300 
0.349 
0.452 
0.536 
0.445 
0.688 
0.185 
55 
0.439 
0.323 
0.373 
0.478 
0.562 
0.471 
0.710 
0.201 
60 
0.465 
0.346 
0.397 
0.504 
0.588 
0.497 
0.731 
0.218 
65 
0.491 
0.370 
0.423 
0.530 
0.613 
0.523 
0.751 
0.236 
70 
0.517 
0.395 
0.448 
0.556 
0.637 
0.549 
0.770 
0.256 
75 
0.543 
0.420 
0.474 
0.582 
0.661 
0.574 
0.788 
0.276 
80 
0.569 
0.445 
0.500 
0.607 
0.684 
0.600 
0.805 
0.297 
85 
0.595 
0.471 
0.526 
0.632 
0.706 
0.624 
0.821 
0.320 
90 
0.619 
0.497 
0.552 
0.656 
0.727 
0.649 
0.836 
0.343 
95 
0.644 
0.523 
0.578 
0.679 
0.747 
0.672 
0.849 
0.367 
100 
0.667 
0.549 
0.603 
0.701 
0.766 
0.695 
0.862 
0.391 
that reduce the effects of handling and that increase 
sample sizes are encouraged regardless of the study 
type chosen. 
Because of the need for estimates derived from fish- 
ery-dependent surveys that accurately reflect fishing 
practices, passive-tagging studies might be the best 
method available, but they still have problems asso- 
ciated with their use. Passive-tagging surveys require 
large numbers of fish to evaluate survival because re- 
capture rates are typically low in the red snapper fish- 
ery (<10%). Furthermore, only 1 of the passive-tagging 
studies evaluated here produced estimates through the 
use of a tag-and-recapture model (Sauls 8 ), although the 
other 2 studies made use of surface-release methods 
(Patterson et ah, 2001; Patterson 4 ). Recent modeling ef- 
forts in other fisheries have shown promise in the use 
of recapture and impairment scaling data to calculate 
relative survival from risk-ratio models (Sauls 8 ; Sauls, 
2014). Continued development of tag-and-recapture 
models would be useful because 1) such models poten- 
tially avoid the biases associated with other estima- 
tion methods, 2) there is an abundance of tagging data 
available, and 3) studies can be designed to directly 
observe the fishery as it is prosecuted. 
Methods for calculating or scaling the level of im- 
pairment of fish caused by effects of CAR fishing have 
proven to be useful for the estimation of release mortal- 
ity for many species, including walleye pollock (Gadus 
chalcogrammus , Gadidae), coho salmon ( Oncorhynchus 
kisutch, Salmonidae), sablefish ( Anoplopoma fimbria, 
Anoplopomatidae), northern rock sole ( Lepidopsetta 
polyxystra, Pleuronectidae), lingcod (Ophiodon elon- 
gatus , Hexagrammidae), Pacific halibut ( Hippoglossus 
stenolepis, Pleuronectidae), and red snapper (Davis et 
ah, 2001; Davis and Ottmar, 2006; Davis, 2007; Camp- 
bell et al., 2010a, 2010b). The impairment scaling met- 
ric for the barotrauma reflex showed a positive logistic 
relationship between impairment level and immediate 
estimates of release mortality in the recreational red 
snapper fishery for both surface-release and caging 
studies (Campbell et ah, 2010a; Diamond and Camp- 
bell, 2009). Because impairment-scaling studies have 
shown significant relationships with release mortality 
in both the surface-release and caging studies, these 
techniques may prove to be useful in tag-and-recapture 
models. 
We did not find a significant reduction in mortal- 
ity by hook type, which was surprising given that the 
regulation requiring circle hooks was thought to be ef- 
fective in reduction of discard mortality by decreasing 
the frequency of gut hooking. However, any effects of 
circle hooks on discard mortality may have been con- 
