Thermal Optima and Tolerance in the Eurythermic Goldfish (Carassius auratus): Relationships between Whole-Animal Aerobic Capacity and Maximum Heart Rate

• Published in: Physiological and biochemical zoology Vol. 87; no. 5; pp. 599 - 611
• Main Authors: Ferreira, Elizabeth O., Anttila, Katja, Farrell, Anthony P.
• Format: Journal Article
• Language: English
• Published: United States University of Chicago Press 01.09.2014
• Subjects: Absolute maximum; Acclimatization; Animals; Carassius auratus; Critical temperature; Freshwater; Goldfish; Goldfish - physiology; Heart Rate; Heat tolerance; Hematocrit; Oxygen; Oxygen Consumption; Temperature; Transition temperature; Water temperature
• ISSN: 1522-2152; 1537-5293; 1537-5293
• DOI: 10.1086/677317

The wide thermal tolerance range of a eurythermic fish (goldfish,Carassius auratus) was used to evaluate how temperature performance curves derived from maximum heart rate (f H) related to those for aerobic scope. For acclimation temperatures of 12°, 20°, and 28°C, optimum temperatures derived from aerobic scope curves (T opt) were 19.9° ± 0.4°, 19.3° ± 0.8°, and 28.7° ± 0.8°C, respectively. The Arrhenius breakpoint temperatures (T AB) for maximumf Hwere 21.5° ± 0.6°, 23.8° ± 0.9°, and 24.6° ± 0.5°C, respectively. TheT QB(temperature where the incremental Q10of maximumf Hdecreased abruptly below 1.9) was 24.0° ± 0.7° and 29.8° ± 0.6°C for the 12° and 28°C acclimation temperatures, respectively, and was within theT optwindow (11.5°–30.3° and 26.9°–30.5°C, respectively), butT QBfor the 20°C acclimation temperature (27.3° ± 0.6°C) was higher than theT optwindow (15.4°–23.2°C). Warm acclimation increased the upper critical temperature (T crit; from 37.2° ± 0.7° to 44.7° ± 11.8°C) as well as the temperature that triggered a cardiac arrhythmia (T arr; from 31.1° ± 0.7° to 39.3° ± 0.4°C). In conclusion, we propose that maximumf Hand its associated rate transition temperatures (T AB,T QB, andT arr) can be used to estimate the upper thermal tolerance of eurythermic as well as stenothermic fish independent of acclimation temperature. All the same, great care is needed with such evaluations. For the goldfish, whileT ABandT QBwere always within theT optwindow for 90% of maximum aerobic scope andT optwas closely associated withT ABfor 12°C-acclimated fish,T QBhad the closest association after 28°C acclimation, and bothT ABandT QBwere above theT optwindow after 20°C acclimation.