Somerton and Donaldson: Parasitism of Lithodes aequispinus by two species of Careproctus 
875 
Results 
Depth distributions of 
golden king crabs and snaiffish 
The 43 hauls sampled on the 1982 survey were ran- 
domly distributed between 192 and 900 m. Over this 
range, golden king crab catch-per-tow (Fig. 3) and 
carapace length (Fig. 4) declined with increasing 
depth. Male and female crab occurred at significantly 
different depths (randomization test, P=0. 005), with 
the median depth of males (203 m) being less than 
that of females (336 m). 
Pink snailfish abundance declined with depth; 
most of the population occurred at depths <450 m 
(Fig. 51. Conversely, red snailfish abundance in- 
creased with depth; most of the population occurred 
at depths >450 m. (Fig. 5). Red snailfish was approxi- 
mately six times more abundant, averaged over the 
entire survey area, than pink snailfish (mean catch 
per haul: red snailfish=4.57, pink snailfish=0.75, to- 
tal number of both species=226). As a result, red 
snailfish were predominate at depths as shallow as 
350 m. The proportion of the individuals that 
were ripe (both sexes combined) did not differ 
significantly between species (chi-square test, 
df=l, P=0.341). Ripe pink snailfish (both sexes 
combined) were found at significantly shallower 
depths than unripe individuals (randomization 
test, P<G.Q01), but ripe and unripe red snailfish 
did not differ in depth (P=0.255). 
Careproctus eggs and larvae 
Snailfish eggs are self adhesive and form com- 
pact masses that are often shaped like casts of 
the interior of the branchial chambers (Fig. 6). 
After hatching, larvae remain grouped together 
within the crab, thus allowing multiple batches 
of larvae to be easily distinguished. Of the 515 
golden king crab examined on the 1982 survey, 
97 contained 128 egg masses or larvae clusters. 
Twenty-three of the crabs had more than one 
egg mass or larval cluster (16 had 2, 6 had 3, 
and 1 had 4 egg masses or larvae clusters). The 
abundance of multiple occurrences relative to 
single occurrences did not differ between 
snailfish species (chi-square test, df=l, P= 
0.111), indicating that the two species were 
equally likely to deposit eggs in previously in- 
fested crabs. Combined over both species, the 
number of egg masses found within infested 
crabs increased with carapace length (linear re- 
gression, n=94, P=0.Q49), indicating that large crabs 
tended to have more multiple occurrences. In three 
200 
400 
600 
800 
Depth (m) 
Figure 3 
Catch per haul by 100-m depth intervals for male (solid) 
and female (dotted) golden king crab. 
Male 
Female 
160 
140 
| 120 
.c 
■2 100 
8 
a 
CO 
<5 80 
O 
60 
40 
• 
160 
• • 9 
,5 s * * 
+C . . 
|! 1 
140 
• 
• 
e® 9 
! 
120 
•• . 
e ® 
• • ? • 
P * 
Q 
® A ® 
ifei 
! * 
*• * • » 
li: ' 
! 
1 • *• • 
- . • ' ; • 
* m • 
100 
*■ * ? * • . 
® ® «* 
ft ® » " 
i S • 
*. i 
80 
t 
* • 
® 
® 
« ® 
I* 
• 
» 
60 
« 
40 
® 
200 400 600 
Depth (m) 
200 400 600 
Depth (m) 
Figure 4 
Carapace length of all crabs captured as a function of depth for 
male (left) and female (right) golden king crab. 
cases of multiple occurrences, eggs or larvae of both 
snailfish species were present. The relative abun- 
