Effect of body size and temperature on respiration of Galaxias maculatus (Pisces: Galaxiidae)

Figures & data

Table 1. Body mass (g, mean ± SD) , specific metabolic rate (g O₂ g^–1 d^–1, mean ± SD) and fish number of Galaxias maculatus at different test temperatures and body masses.

W (g)	0.1	0.5	1.0	>1.5	Total mean by T
T (°C)
5	0.22 ± 0.06 0.0024 ± 0.0005 n = 3	0.45 ± 0.18 0.0017 ± 0.0005 n = 3	0.99 ± 0.14 0.0016 ± 0.0001 n = 4	2.12 ± 0.63 0.0008 ± 0.0001 n = 2	0.0017 ± 0.0006 n = 12
9	0.21 ± 0.06 0.0044 ± 0.0015 n = 5	0.5 ± 0.21 0.0037 ± 0.0004 n = 3	1.07 ± 0.14 0.0025 ± 0.0008 n = 3	1.97 ± 0.55 0.0021 ± 0.0005 n = 7	0.0031 ± 0.0013 n = 18
13	0.24 ± 0.02 0.0066 ± 0.0014 n = 3	0.53 ± 0.19 0.0056 ± 0.0016 n = 3	0.96 ± 0.11 0.0047 ± 0.0006 n = 4	1.54 ± 0.26 0.0032 ± 0.0004 n = 4	0.0048 ± 0.0015 n = 14
17	0.22 ± 0.99 0.0077 ± 0.0028 n = 2	0.51 ± 0.12 0.0085 ± 0.0005 n = 3	1.05 ± 0.19 0.0062 ± 0.0004 n = 4	1.40 ± 0.16 0.0058 ± 0.0013 n = 2	0.0070 ± 0.0015 n = 11
21	0.27 ± 0.02 0.0093 ± 0.0010 n = 3	0.53 ± 0.15 0.0080 ± 0.0011 n = 4	1.06 ± 0.16 0.0081 ± 0.0011 n = 2	1.32 ± 0.09 0.0099 ± 0.0010 n = 2	0.0087 ± 0.0012 n = 11
Total mean by W	0.0056 ± 0.0027 n = 16	0.0056 ± 0.0027 n = 16	0.0041 ± 0.0022 n = 17	0.0036 ± 0.0028 n = 17

Figure 1. Relationships between the log-specific respiration rate and log-body mass (W, g) of Galaxias maculatus at different temperatures (T, °C). Plotted lines represent best-fit regressions for each temperature.

Figure 2. Relationship between the specific respiration rate and temperature (T, °C) of Galaxias maculatus at different body masses (W, g). Plotted lines represent best-fit regressions for each body mass.

Figure 3. Specific respiration rates under the combined effects of body mass and temperature of Galaxias maculatus. model for fitted curves at varying temperatures. Plotted lines represent best-fit regressions for each temperature.

Table 2. Predictive models of specific respiration rate (R, g O₂ g^–1 d^–1) of Galaxias maculatus using fish body mass (W, g) and water temperature (T, °C) as explicative variables (coefficient estimation ± SD).

Model	Temperature	RA ± SD	RB ± SD	RQ ± SD	R^2	P
R = RA W^RB	5	0.001 ± 0.09	−0.34 ± 0.10		0.53	0.007
R = RA W^RB	9	0.003 ± 0.06	−0.32 ± 0.06		0.65	<0.0001
R = RA W^RB	13	0.004 ± 0.06	−0.32 ± 0.07		0.60	0.001
R = RA W^RB	17	0.006 ± 0.04	−0.25 ± 0.06		0.71	0.002
R = RA W^RB	21	0.007 ± 0.06	−0.10 ± 0.10		0.14	0.352
R = RA W^RB e ^RQ T	5-17	0.0007 ± 0.09	−0.31 ± 0.04	0.13 ± 0.01	0.84	<0.0001

Figure 4. Observed vs predicted specific respiration rate of Galaxias maculatus. Solid line indicates linear regression between observed and predicted values and dotted line indicates 1:1 relationship.