108 
Fishery Bulletin 112(2-3) 
labile 4 
Results of logistic regression used to examine effects of size (carapace 
length) and sex on the likelihood of death or capture in ghostfishing gear for 
red king crabs ( Paralithodes camtschaticus ) in Womens Bay, Kodiak Island, 
Alaska, during the period of 1991-2008. Z=Z- score; improbability. “Size” is 
the carapace length of the crab. 
Parameter 
Estimate 
Standard error 
Z 
P 
Crabs that died 
in ghostfishing gear 
Constant 
-4.69 
1.30 
-3.61 
0.000 
Size 
0.02 
0.01 
1.92 
0.055 
Sex (female) 
-0.22 
0.61 
-0.37 
0.714 
Crabs that were caught in ghostfishing gear 
Constant 
-2.57 
0.82 
-3.12 
0.002 
Size 
0.01 
0.01 
0.89 
0.373 
Sex (female) 
0.63 
0.40 
1.58 
0.114 
0.30 
0.25 ■ 
0.20 
c 
0 
1 0.15 
Q. 
O 
a. 0.10 
0 05 • 
0.00 
Killed 
Caught 
42 
16 
53 
10 
1 
33 
36 
1 
1 
e.0 
ifr 30 60 
yOO V2.0 
X 
6,0* 
Size range (mm carapace length) 
Figure 4 
Proportion of tagged red king crabs ( Paralithodes 
camtschaticus) that died (black bars) or were caught 
(gray bars) in ghostfishing gear in Womens Bay, Ko- 
diak Island, Alaska, during the period of 1991-2008. 
Note that no crabs with carapace lengths between 40 
and 60 mm were caught or killed. The number above 
each set of bars represents the total number of crabs 
in each size category. The line with the long dashes in- 
dicates the overall proportion of tagged crabs killed in 
ghostfishing gear, and the line with the short dashes 
indicates the overall proportion caught in ghostfishing 
gear. 
to 90% (High and Worlund, 1979) and mortality of 
crabs trapped in such pots may be no higher than 17% 
(Godpy et al., 2003), these rates of escape and mortality 
do not reflect rates for most of the pots in our study be- 
cause many of the pots observed in our study targeted 
the Dungeness crab. 
Current regulations in Alaska 
require escape rings on Dungeness 
crab pots to be 121 mm, smaller 
than the 159 mm required for red 
king crab pots (ADFG 4 ), but most of 
the pots found during our study that 
were of a type other than the Dunge- 
ness crab pot did not have escape 
rings. Therefore, we would expect 
much lower escape rates for red king 
crabs caught in the pots observed 
in this study. Estimates for mortal- 
ity rates have been much lower for 
crabs trapped in red king crab pots 
than for crabs caught in many other 
pot types: 31-46% mortality of blue 
swimmer crabs ( Portunus pelagicus) 
in blue swimmer crab pots (Camp- 
bell and Sumpton, 2009), 52% of 
Dungeness crabs in Dungeness crab 
pots (Breen, 1987), and 95% mortali- 
ty of snow crabs ( Chionoecetes opilio) in snow crab pots 
(Hebert et al., 2001). 
Given the relatively small escape rings of pots de- 
signed for much smaller crab species and the absence 
of escape rings in the pots observed in this study, the 
majority of red king crabs found trapped in pots likely 
would have been unable to escape and eventually would 
have died. Results from our study suggest that red king 
crabs <60 mm CL are less likely to be caught or killed 
in pots than crabs of other sizes and that crabs >140 
mm CL are more likely than crabs <140 mm to become 
trapped or to die in pots; however, these findings were 
not statistically significant and may have been driven 
to some extent by small sample sizes for crabs in the 
largest and smallest size categories. Although small- 
er crabs probably are more likely to escape from pots 
(High and Worlund, 1979), our data indicate that crabs 
>60 mm CL are vulnerable to the types of ghost pots 
observed in this study. 
Escape of red king crabs from pots is asymptotic 
over time, and the number of crabs escaping levels off 
at about 8 days (High and Worlund, 1979). We esti- 
mated that only 8 of the 20 crabs released from pots 
had been trapped for less than 8 days. If the remaining 
12 crabs had been able to escape, then they probably 
would have done so before they were rescued. Addi- 
tionally, divers in this study actively disabled 89 intact 
pots that would otherwise have continued to ghost fish, 
likely substantially lowering the effect of ghost fishing 
in Womens Bay. Given these observations, we believe 
that the true mortality rate from ghostfishing gear is 
somewhere between our conservative and upper esti- 
mates and is most likely closer to the upper estimate. 
Although our estimate of the rate of mortality of red 
king crabs from sources other than ghost fishing is rea- 
sonably precise, it is almost certainly an underestimate 
because it does not account for mortalities that may 
occur during molting, which is physiologically stressful 
