610 
Fishery Bulletin 96(3), 1998 
High oxygen treatments 
Low oxygen treatments 
Routine respiration rate (mg OJ[q • h) 
Figure 3 
Frequency histogram of respiration rates for young-of-the-year Atlantic sturgeon 
exposed to either high (7 mg/L) or low levels (3 mg/L) of dissolved oxygen. Mea- 
sures taken at the initiation of the experiment (hour 0) are stippled. 
served. This may be attributable to 
a higher designated oxygen level 
for hypoxic treatments (<5 mg/L), 
differences between the two spe- 
cies, or an ontogenetic effect. Ju- 
venile white sturgeon were substan- 
tially smaller (initial weight 0.5 
grams) than those used in our study 
(mean initial weight=23.7 grams). 
Our study was unique in exam- 
ining the effects of long-term hy- 
poxia on routine metabolism. 
Other studies have examined the 
effects of hypoxia on sturgeon res- 
piration in short-term respirom- 
etry studies (Table 5). Investiga- 
tions on white sturgeon and Sibe- 
rian sturgeon ( Acipenser baeri) 
have indicated reduced rates of 
respiration under hypoxic condi- 
tions. An ontogenetic trend of de- 
creasing routine metabolic rates 
with increased mass, which is typi- 
cal in fishes, was also suggested in 
the comparison of studies. Meta- 
bolic rates under normoxic condi- 
tions ranged from 0.9 mg d/lg-h) 
(1-2 g fish) to 0.055 mg O^fg-h) 
(1800-g fish). Metabolic rates (0.2 
Table 5 
Summary of studies on hypoxia and routine metabolism for sturgeons. Oxygen concentrations and consumption rates have been 
converted to common units (mg OJh or mg O^g-h) from reported units (e.g. mm Hg or pmol Oj/kglg h) for several of the studies. 
Wt = wet weight; Hyp = hypoxia treatment; Norm = normoxia treatment; Swim = velocities were provided in respirometer to 
induce swimming velocities; S = salinity; and T = temperature. 
Species 
Wt 
(g) 
Treatments 
Routine 
metabolism 
mg/(g-h) 
S 
(ppt) 
T 
(°C) 
Study 
duration 
Reference 
Acipenser 
transmontanus 
0.5-5 
Hyp: 4.7 - 5.7 mg/L 
Norm: 6.8 - 8.2 mg/L 
Not measured 
0 
15, 20, 25 
30 d 
Cech et al., 1984 
A. baeri 
1-2 
High density 
Low density 
0.3 to 0.5 
0.4 to 0.9 
0 
22-24 
2-12 h 
Khakimullin, 1987 
A. baeri 
3-7 
Routine 
Swim: 5-30 cm/sec 
0.3 to 0.7 
0.4 to 3.6 
0 
22-24 
3 h 
Khakimullin, 1988 
A. oxyrinchus 
12-69 
Hyp: 2. 5-4. 4 mg/L 
Norm: 6. 3-7. 4 mg/L 
0.1 to 0.2 
0.2 to 0.3 
1.8-2. 5 
19, 26 
10 d 
This study 
A. transmontanus 
950 
Hyp: 1.7-6. 3 mg/L 
Norm: 9.8 mg/L 
~0 to 0.015 
0.079 
0 
15 
4.5 h 
Burggren and 
Randall, 1978 
A. baeri 
1800 
Hyp: 1.3-3. 8 mg/L 
Norm: 8.2 mg/L 
0.023 
0.055 
0 
15 
3.5 h 
Nonnotte et ah, 1993 
A. transmontanus 
2000 
Hyp: 4. 7-5. 9 mg/L 
Norm: 7.7-8.9mg/L 
0.090 
0.098 
0 
0 
18 
24 h 
Ruer et ah, 1987 
