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Temperature and CO2 Effects on Blood O2 Equilibria in Northern Squawfish, Ptychocheilus oregonensis

Canadian Journal of Fisheries and Aquatic Sciences
By: , , and 
https://doi.org/10.1139/f94-003

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Abstract

In vitro blood O2 equilibrium curves were constructed at 9, 15, 18, and 21 °C from temperature-acclimated northern squawfish, Ptychocheilus oregonensis. At low (<1 mm Hg, 1 mm Hg = 133.32 Pa), P50s generally showed variable increases with temperature from 3.6 mm Hg at 9 °C to 8.7 mm Hg at 21 °C, leading to whole-blood temperature effects (ΔH, kilocalories per mole O2) ranging from a low +4.4 at 15–18 °C to a peak −21.2 at 18–21 °C. High- (7.6 mm Hg) conditions decreased blood pH and increased P50s at each temperature (Bohr factor). Bohr factors (Φ) ranged from −0.46 at 21 °C to −0.70 at 18 °C. Considered together, ΔH and Φ values suggest an optimal temperature range of 15–18 °C for hemoglobin O2 loading and unloading in northern squawfish. Nonbicarbonate buffer values ranged from −10.04 at 21 °C to −14.13 at 9 °C. Overall, the high O2 affinities and hyperbolic blood O2 equilibrium curves of northern squawfish resemble those of other large cyprinids (e.g., common carp, Cyprinus carpio, tench, Tinca tinca, Sacramento blackfish, Orthodon microlepidotus) indicating a better ability to tolerate hypoxic environments than sympatric rainbow trout, Oncorhynchus mykiss. High northern squawfish blood O2 capacities and Φs suggest high aerobic capacity, especially at temperatures <21 °C.

Publication type Article
Publication Subtype Journal Article
Title Temperature and CO2 Effects on Blood O2 Equilibria in Northern Squawfish, Ptychocheilus oregonensis
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/f94-003
Volume 51
Issue 1
Year Published 1994
Language English
Publisher NRC Research Press
Contributing office(s) Western Fisheries Research Center
Description 7 p.
First page 13
Last page 19
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