Moiseev et al: Effects of pot fishing on the physical condition of Chionoecetes opilio and Chionoecetes bairdi 
239 
the pot for 55 days in experiment 9 (Table 1). Samples 
of hepatopancreas were frozen in plastic bags, stored, 
and transported in the same manner as that used for 
the samples of hemolymph. The hepatopancreas copper 
content of individual crabs was determined by atomic 
absorption spectrophotometry (Shimadzu AA-6800, 
Shimadzu Corp., Kyoto, Japan) with the method of 
Kirichenko et al. (2005). In experiments 6 and 7, copper 
content was determined in samples of hepatopancreas 
from only those individual snow crab and southern Tan- 
ner crab in which [He] was twice as low as the mean 
[He] in the crabs immediately after capture. 
Results 
Dependence of crab vitality on haul frequency 
Our experiments, in which we examined the physiologi- 
cal capacity of snow crab and southern Tanner crab to 
survive the variable environment associated with haul 
and return to the sea revealed that the condition of an 
animal was strongly dependent on the time interval 
between pot lifts. During repeated pot hauls at short 
time intervals (<3 days) in experiments 5, 6, and 7, we 
observed a rapid reduction in reflex responses and lo- 
comotor activity in crabs. After 2-3 lifts in pots, the 
vitality of crabs was close to the minimum (VI=0-1). 
In experiment 7, the total number of pot lifts was 9. 
After the first 2 lifts, VI= 1—2; after the third to sixth 
lifts, VI=0-1; and after the last 2 lifts, VI approached 
0. During repeated pot hauls at long time intervals (>3 
days) in experiments 1 and 3, the condition of the crabs 
did not significantly change or was only moderately 
suppressed (VI=2-3). At time intervals of more than 
a week between pot hauls (experiments 2, 4, 8, and 9), 
the condition of most crabs was not significantly differ- 
ent from the condition of freshly caught animals. 
Changes in hemocyanin concentration depending on 
hauling interval 
Long intervals 03 days) In experiment 1, 3 pot lifts 
were made: the first lift on the fifth day, the second lift 
on the ninth day, and the third lift only on the 25th day 
because of ocean conditions (Table 1). We observed a sig- 
nificant decrease in [He] in the hemolymph of snow crab 
and southern Tanner crab during this experiment: both 
in crabs in which blood was sampled only once (Fig. 3, A 
and B) and in crabs in which blood was sampled more 
than once (Fig. 4, A and B). The main decrease in [He] 
occurred during the time that elapsed between the cap- 
ture of crabs and the second pot lift. During the next 16 
days and up to the 25th day of the experiment, further 
decreases in [He] were observed but were not significant 
(Fig. 3, A and B). 
In experiment 3, mean [He] in the hemolymph of 
snow crab used in our experiments decreased by 51%, 
after the first pot lift on the seventh day, compared 
A 
B 
Days 
Figure 3 
Changes in mean hemocyanin concentration [He] in 
(A) southern Tanner crab (Chionoecetes bairdi ) and (B) 
snow crab (C. opilio) sampled for hemolymph only once 
during repeated pot hauls at long time intervals (>3 
days) in experiments conducted on 18 May-12 June 
2006 in area I of the Bering Sea to study the effects 
of commercial pot fishing on the physical condition of 
these species (see Fig. 1 for location of area I). Open 
bars indicate mean [ He] observed in crabs sampled im- 
mediately after capture (18 individuals for southern 
Tanner crab and 15 for snow crab), and shaded bars 
indicate mean [He] observed in crabs sampled after 
repeated pot hauls (for both species of crabs, 4-7 in- 
dividuals were sampled after each pot haul). Asterisks 
(*) indicate values significantly different by Student’s 
t-test (PcO.Ol), compared with mean [He] observed in 
crabs sampled immediately after capture. Error bars 
indicate ±1 standard error of the mean. 
with the mean [He] found in control samples collected 
immediately after capture, and the difference was signif- 
icant (Student’s Atest, PcO.Ol). After the second pot lift 
on the 14th day, large variations in [He] in the hemo- 
lymph of snow crab were observed, and the difference 
between experimental and control animals, therefore, 
was not significant (data not shown). 
