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Fishery Bulletin 111(3) 
ter the pot had soaked for 4 days. After an additional 8 
days of pot soaking, crabs recovered completely: all ani- 
mals were alive and their condition did not significantly 
differ from the condition of freshly caught animals. 
In our experiments, comparisons of the different 
hauling conditions also revealed that the vitality of 
In our experiments, [He] was 
selected as an objective mea- 
surement for the assessment of 
the effects of pot fishing on the 
physical condition of snow crab 
and southern Tanner crab. In 
addition to serving as a practi- 
cal and simple indicator, it can 
be easily related to respiratory 
function, which can be impaired 
because of air exposure and gill 
disorders that result from fish- 
ing and handling operations. 
The [He] in crustacean he- 
molymph is determined by the 
balance between anabolism and 
catabolism of the protein. The 
turnover rate of crustacean He 
is thought to be slow in usual 
steady-state conditions. Half- 
times for clearance of 125 I-labeled 
He have been reported to be 25.5 
and 36 days in American lobster 
( Homarus americanus ) and Ca- 
ribbean spiny lobster ( Panulirus 
argus) (Senkbeil and Wriston, 
1981). A more rapid synthesis 
of He can be induced by vari- 
ous environmental factors, such 
as changes of ambient salin- 
ity (Gilles, 1977; Pequeux et al., 
1979) and by moderate chronic 
hypoxia (Hagerman and Baden, 
1988; deFur et ah, 1990; Spicer 
and Baden, 2001). 
A decrease in [He] in hemo- 
lymph of crustaceans may be 
caused by starvation. It has long 
been noted that [He] is related to the nutritional state 
of crustaceans under natural conditions (Dali, 1974; 
and references therein), leading some researches to 
suggest that, in times of plenty, He serves not only as 
an 0-2 carrier but also as a storage protein. Terwilliger 
(1998) noted, “This may occur, although storing ex- 
Figure 9 
Light micrographs of damages to gills in snow crab ( Chionoecetes opilio) and south- 
ern Tanner crab (C. bairdi) from our study of the effects of pot fishing on the 
physical condition of these species: (A) deformation of lamellae; note the irregu- 
lar shape of the marginal channels and vesicular swellings; (B) torn connections 
of pillar cells in the dilated parts of the lamellae; (C) swollen marginal canals 
filled with hemocytes and collapsed lamellae walls (marked by arrow); and (D) 
melanized inclusions in lamellae (arrows); note the deformation of lamellae and 
torn connections of pillar cells. Hematoxylin and eosin stains were used. Ab- 
breviations: mc=marginal canal; sl=swelling of lamellae; pc=normal pillar cells; 
t=torn pillar cells; and h=hemocytes. Scale bar=100 pm. 
animals was strongly dependent 
not only on the number of but 
also on the length of time be- 
tween pot lifts. During repeated 
pot hauls at short intervals (<3 
days), we observed a rapid de- 
cline in vitality of crabs. When 
we increased hauling intervals 
to >3 days, the condition of crabs 
did not change significantly or 
was suppressed only moderately. 
Effects of pot fishing on hemocya- 
nin concentration 
