106 
Fishery Bulletin 112(2-3) 
Table 2 
Types of ghost pots found in Womens Bay, Kodiak Island, Alaska, by divers over the period of 
1991-2008 and classification according to whether a pot was still intact and whether it was found 
upright or upside down. “Unknown” indicates that the type of pot could not be assessed. “Un- 
known condition” indicates that the divers could not determine if the pot was intact. 
Type 
Number 
found 
Number 
intact 
Percentage 
intact (%) 
No. found 
upside-down 
Unknown 
condition 
Dungeness 
70 
46 
66 
8 
2 
Webbed 
42 
30 
71 
2 
2 
Home made 
20 
10 
50 
2 
1 
Store bought 
7 
3 
43 
1 
2 
Unknown 
4 
0 
0 
0 
2 
Total 
143 
89 
62 
13 
9 
dive was performed. The amount of time crabs spent 
in the trap averaged 38 (standard deviation [SD] 23 
days) for crabs that died and 10 (SD 8 days) for crabs 
that were alive when released. The red king crab ac- 
counted for the majority of the organisms found in 
crab pots. Rarely found species included sculpins 
( Myoxocephalus spp. ), southern Tanner crab, and 
Dungeness crab ( Metacarcinus magister\ sensu Schram 
and Ng, 2012). 
Over the study period in Womens Bay, divers located 
143 pots, of which 60 were found during the tracking of 
tagged crabs and 83 were found during other projects 
(Table 2). Of these pots, about half were Dungeness 
crab pots, which have the shape of a squat cylinder 
and a frame of steel covered with a mesh of stainless 
steel. Steel-frame pots, which are large, commercial- 
size pots with steel frames construct- 
ed in the shape of a pyramid, cone, 
or rectangle and which are covered in 
webbing that is usually made of nylon, 
were the next most frequently encoun- 
tered type of pot, followed by home- 
made pots. Only a few sport pots, which 
are smaller, light-weight pots that are 
commercially produced and easily re- 
trievable by hand, and pots of unknown 
type were found. Of the crab pots that 
were encountered, 62% were intact, in- 
dicating that those pots lacked a biode- 
gradable release and were capable of 
ghost fishing. Additionally, other than 
the Dungeness crab pots, most of the 
pots lacked escape rings. Likely reasons 
for pot loss, determined on the basis of 
field observations, included release of 
a pot after a line was cut by boat pro- 
pellers; entanglement of a pot in lines 
that were dragged by commercial barge 
towing bridals, sinking of a float due to 
biofouling on the lines, and breakage of 
a line by ice. 
The conservative estimate of the overall rate of loss 
of tagged crabs from all sources, including sources of 
mortality, was about 10% less than the upper estimate; 
however, the upper estimate of the predicted mortality 
rate from ghost fishing was nearly 300% higher than 
the conservative estimate of the predicted mortality 
rate from ghost fishing (Table 3). Other sources of loss 
did not vary substantially between the 2 estimates. 
Overall annual mortality estimated from tagging data 
ranged from 40% to 56% for the conservative and upper 
estimates (Fig. 3). Using the calculated rate of mortal- 
ity of tagged crabs in Womens Bay and applying it to 
the whole population of red king crab in this bay, we 
estimated that ghost fishing killed between 16% and 
37% of the population per year, according to our con- 
servative and upper estimates (Fig. 3). 
Table 3 
Instantaneous loss rates for tagged red king crabs ( Paralithodes camts- 
cliaticus) and tags in Womens Bay, Kodiak Island, Alaska, during the 
period of 1991-2008. The conservative estimate for ghostfishing mortal- 
ity was determined on the basis of counts of crabs that died in ghost- 
fishing gear. For the upper estimate, we assumed that all crabs caught in 
ghost-fishing gear and released by divers would have died. The estimate 
for experimental error includes handling mortality and tags that fell off 
crabs. The “All” category represents all sources of crab loss and is the 
parameter fitted by the exponential decay model (see the model in the 
Materials and methods section of the text for details). Standard errors of 
the mean are presented in parentheses. 
Source of loss 
Loss rate (days -1 ) 
Conservative 
Upper 
All 
Molting 
Ghostfishing mortality 
Other mortality 
Lost tag 
Experimental error 
0.00709 (0.00003) 
0.00476 (0.00017) 
0.00056 (0.00007) 
0.00081 (0.00017) 
0.00081 (0.00016) 
0.00015 (0.00024) 
0.00782 (0.00004) 
0.00466 (0.0003) 
0.00147 (0.00023) 
0.00075 (0.00017) 
0.00077 (0.00017) 
0.00016 (0.00008) 
