Pachón | Micos | Surface | Data origin | ||
a | Whole-body minimal metabolic rate (mg O2 hour−1 per 5-g fish) | 0.8328* | 0.929† | 1.026* | Published data |
b | Whole-body oxygen demand (mg O2 hour−1) | 0.686‡ | 0.766‡ | 0.846‡ | a(4 g ÷ 5 g)0.862 |
c | Brain mass (g) | 0.027 | 0.031 | 0.034 | 4 g × organ mass scaling relationships in table S2 |
d | Relative brain mass (% body weight) | 0.68 | 0.78 | 0.85 | c ÷ 4 g |
e | Brain metabolic rate (mg O2 hour−1 g wet mass−1) | 1.603 | 1.603 | 1.603 | Data from the current study |
f | Brain oxygen demand (mg O2 hour−1) | 0.043 | 0.050 | 0.055 | e × c |
g | Relative brain cost (% body O2 demand) | 6.27 | 6.52 | 6.50 | f ÷ b |
h | Eye mass (g) | 0 | 0.038 | 0.090 | 4 g × organ mass scaling relationships in table S2 |
i | Relative eye mass (% body weight) | 0 | 0.95 | 2.25 | h ÷ 4 g |
j | Eye metabolic rate (mg O2 hour−1 g wet mass−1) | 0 | 0.525 | 0.525 | Data from the current study |
k | Eye oxygen demand (mg O2 hour−1) | 0 | 0.020 | 0.047 | j × h |
l | Relative eye cost (% body O2 demand) | 0 | 2.61 | 5.56 | k ÷ b |
m | Neural tissue (eyes plus brain) oxygen demand (mg O2 hour−1) | 0.043 | 0.070 | 0.102 | f + k |
n | Neural tissue cost (% body O2 demand) | 6.27 | 9.14 | 12.06 | m ÷ b |
o | Cost of vision (% body O2 demand) | 0 | 3.52 | 6.97 | (mMicos − mPachón) ÷ bMicos |
(msurface − mPachón) ÷ bsurface |
*Data taken from Moran et al. (19).
†Estimated as a rate equidistant between Pachón and surface ecotypes based on data from Hüppop (11).
‡Mass metabolism scaling exponent (0.862) taken from Moran et al. (19).