Moiseev et al: Effects of pot fishing on the physical condition of Chionoecetes opilio and Chionoecetes bairdi 
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Field experiments 
Effects of repeated pot hauling on crabs Snow crab and 
southern Tanner crab were placed in commercial crab 
pots. In experiments 1, 3, 5, 6, and 7 we used a single 
pot of the American-type (Table 1). Before deployment 
of the pots, the entrance tunnels of pots were sewn shut 
with webbing to prevent individuals in our experiment 
from escaping and other crabs and big animals (e.g., 
mammals, big fishes) from entering the pots from the 
environment. During our experiments, crabs were not 
fed. The pots were sunk and hauled back to the sur- 
face at different frequencies. During the preparation of 
pots for the next deployment, crabs were maintained in 
tanks with running seawater for periods from 10-15 min 
to 1-2 h. Experiments that involved repeated pot hauls 
were divided into 2 sets, depending on the hauling 
intervals: 1) short time intervals (<3 days) — experiments 
5, 6, and 7 — or 2) long time intervals (>3 days) — experi- 
ments 1 and 3 (Table 1). Both control animals and those 
animals that were collected for experiments had been 
lifted to the water surface during capture. Hereafter, 
the number of pot lifts we specify includes only the lifts 
made during the experiment, unless otherwise stated. 
Upon retrieval of pots, mortality was noted and the 
condition of each crab was monitored with the vital- 
ity index. Criteria for the index incorporated reflexes, 
spontaneous movements of appendages, and righting 
behavior (i.e., an animal’s ability to turn from a ven- 
trum-up position to normal orientation): 
0 = no signs of life: no movement of legs or mouthparts; 
1 = weak, slow movement of legs or maxillipeds, at- 
tempts at righting behavior, third pair of maxilli- 
peds droop open and retract to cover small mouth 
parts when touched by pencil, chelae grab any ob- 
ject slightly and not for long (up to 30 s); 
2 = moderate movement of legs, righting time of 10-60 s 
in water bath, fast movement of maxillipeds, chelae 
grab any object strongly and for long periods (up to 
1.5 min); 
3 = fast, active movement of legs, righting time of 5-40 
s in water bath or on the sorting table, fast move- 
ment of maxillipeds, chelae grab any object strong- 
ly and for long periods (> 2 min), threat display. 
Effects of long-term starvation in pots on crabs In ex- 
periments 2, 4, 8, and 9, to investigate the effects of 
starvation, pots containing snow crab or southern Tan- 
ner crab were soaked (i.e., pots were deployed in the 
sea) for extended periods of time (14-55 days) (Table 
1). Experiment 2 was combined with experiment 1. In 
the course of experiment 1, after the second lift of the 
pot, we added 5 freshly caught snow crab and 6 south- 
ern Tanner crab. The pot was lifted to the surface 16 
days later; ocean conditions caused this long hauling 
interval (Table 1). At the end of all these experiments, 
the amount of meat in crab limbs was assessed by vi- 
sual comparison of the slices of merus after boiling 
versus schematic representation of slices of merus in 
crab with varying degrees of meat content (Borisov et 
ah, 2003). 
Effects of long-term exposure to air on crabs Experiment 
10 was designed to investigate the effects of long-term 
exposure to air on snow crab. It was replicated 3 times 
(Table 1). Snow crabs were kept out of the water on the 
deck from 6 to 8 h after capture. Animals were covered 
with a tarpaulin, which periodically was irrigated with 
seawater to protect the crabs from desiccation. Surface 
water temperatures were 6-7°C, and air temperatures 
were 7-8°C. Thereafter, 10-15 individuals were placed 
in conical pots of the Japanese type, and these pots 
were deployed in the sea. In each repetition of the ex- 
periment we used a single pot which was hauled 2-3 
times at intervals of 2 days. 
Sampling of hemolymph 
Sampling of hemolymph in crabs from commercial 
catches was completed within 30 min after a pot had 
appeared at the water surface, the length of time re- 
ferred to hereafter as immediately after capture. Sam- 
ples of hemolymph taken from crabs immediately af- 
ter capture served as control samples. Most crabs from 
which control hemolymph samples were taken were dis- 
carded, but, in experiments 1 and 3, some crabs were 
used in the experiments after they had control samples 
of blood taken from them. In experiment 9, control sam- 
ples of hemolymph were taken from crabs immediately 
after capture, as well as from the crabs exposed to air 
for 6-8 h before deployment of a pot. In most cases, 
crabs used for control samples of blood and crabs for 
our experiments were collected from the same commer- 
cial catches. In some cases, because of ocean conditions, 
crabs used for control samples of blood were collected 
from other commercial catches, but they always were 
collected from catches in the same fishing area at a dis- 
tance <0.9 km from the experimental pots and always 
during the periods of our experiments. Upon retrieval of 
pots, during our experiments that involved repeated pot 
hauls, hemolymph was sampled from some of the crabs 
used in experiments; these individuals were discarded 
after blood was sampled. Only in experiments 1 and 3, 
crabs from which hemolymph samples were taken re- 
main in the pot. In experiment 1, in some individuals, 
blood was sampled repeatedly (3 or 4 times). 
Hemolymph (3-5 mL) was quickly sampled from in- 
dividual crabs with a syringe through the arthrodial 
membrane at the base of the fourth or fifth pair of legs. 
All manipulations were carried out quickly and careful- 
ly (the duration of crab exposure to air was not more 
than 10 min). The hemolymph samples were frozen and 
stored below -30° while on board. For transport to the 
biochemistry laboratory, they were kept on ice. Before 
analysis, the samples of hemolymph were thawed at 
4°C and centrifuged for 15 min at 12,000 rpm, and the 
supernatant was collected. In snow and southern Tan- 
