Unusual aerobic performance at high temperatures in juvenile Chinook salmon,<i>Oncorhynchus tshawytscha</i>

Poletto, Jamilynn B.; Cocherell, Dennis E.; Baird, Sarah E.; Nguyen, Trinh X.; Cabrera-Stagno, Valentina; Farrell, Anthony P.; Fangue, Nann A.

doi:10.1093/conphys/cow067

Cited by 47 publications

(70 citation statements)

References 71 publications

(82 reference statements)

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“…Thermal windows are typically narrow during early life and adult spawning stages and wider during juvenile and young adult stages (Pörtner and Farrell, 2008;Poletto et al, 2017;Fig. 1B).…”

Section: Evolutionary Modulation Of Oclttmentioning

confidence: 99%

Oxygen- and capacity-limited thermal tolerance: bridging ecology and physiology

Pörtner

Bock

Mark

2017

Journal of Experimental Biology

440

357

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Observations of climate impacts on ecosystems highlight the need for an understanding of organismal thermal ranges and their implications at the ecosystem level. Where changes in aquatic animal populations have been observed, the integrative concept of oxygen-and capacitylimited thermal tolerance (OCLTT) has successfully characterised the onset of thermal limits to performance and field abundance. The OCLTT concept addresses the molecular to whole-animal mechanisms that define thermal constraints on the capacity for oxygen supply to the organism in relation to oxygen demand. The resulting 'total excess aerobic power budget' supports an animal's performance (e.g. comprising motor activity, reproduction and growth) within an individual's thermal range. The aerobic power budget is often approximated through measurements of aerobic scope for activity (i.e. the maximum difference between resting and the highest exerciseinduced rate of oxygen consumption), whereas most animals in the field rely on lower (i.e. routine) modes of activity. At thermal limits, OCLTT also integrates protective mechanisms that extend time-limited tolerance to temperature extremes -mechanisms such as chaperones, anaerobic metabolism and antioxidative defence. Here, we briefly summarise the OCLTT concept and update it by addressing the role of routine metabolism. We highlight potential pitfalls in applying the concept and discuss the variables measured that led to the development of OCLTT. We propose that OCLTT explains why thermal vulnerability is highest at the whole-animal level and lowest at the molecular level. We also discuss how OCLTT captures the thermal constraints on the evolution of aquatic animal life and supports an understanding of the benefits of transitioning from water to land.

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“…Thermal windows are typically narrow during early life and adult spawning stages and wider during juvenile and young adult stages (Pörtner and Farrell, 2008;Poletto et al, 2017;Fig. 1B).…”

Section: Evolutionary Modulation Of Oclttmentioning

confidence: 99%

Oxygen- and capacity-limited thermal tolerance: bridging ecology and physiology

Pörtner

Bock

Mark

2017

Journal of Experimental Biology

440

357

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“…In fact, for many fish species from temperate to tropical systems, FAS often decreases over the entire temperature range experienced by a species evaluated whereas AAS has been reported to display varying patterns from more or less bell-shaped to continuously increasing or remaining stable (e.g. Clark et al 2011;Healy and Schulte 2012;Norin et al 2014;Poletto et al 2017;Steinhausen et al 2008;Tirsgaard et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Exploring key issues of aerobic scope interpretation in ectotherms: absolute versus factorial

Halsey

Killen

Clark

et al. 2018

Rev Fish Biol Fisheries

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Aerobic scope represents an animal's capacity to increase its aerobic metabolic rate above maintenance levels (i.e. the difference between standard (SMR) and maximum (MMR) metabolic rates). Aerobic scope data can be presented in absolute or factorial terms (AAS or FAS, respectively). However, the robustness of these calculations to noise or variability in measures of metabolic rate can influence subsequent interpretations of patterns in the data. We explored this issue using simple models and we compared the predictions from these models to experimental data from the literature. First, we investigated the robustness of aerobic scope calculations as a function of varying SMR when MMR is fixed, and vice versa. While FAS is unexpectedly robust to variability in SMR, even in species with low aerobic scopes, AAS is less sensitive to variation in SMR than is FAS. However, where variation in MMR is the main concern, FAS is more robust than AAS. Our findings highlight the equal importance of minimising variability in MMR, rather than just the variability in SMR, to obtain robust aerobic scope estimates. Second, we analysed metabolic rate accounting for locomotor speed and body mass for swimming fish. The interactions among these factors in relation to AAS and FAS are complex and the appropriate metric is dependent on the specific ecophysiological context of the research question. We conclude with qualified recommendations for using and interpreting AAS and FAS.

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“…28•C -34•C; Q10 = 3.01). This pattern has been observed in juvenile C. porosus at lower temperatures and reflects an exponential curve (Wright, 1986 and rainbow trout (Oncorhynchus mykiss) (Verhille et al, 2016;Poletto et al, 2017). For example, AAS of O. tshawytscha was maintained across a wide thermal range approaching upper tolerance limits (i.e.…”

Section: Thermal Independence Of Aerobic Scopementioning

confidence: 54%

“…For example, AAS of O. tshawytscha was maintained across a wide thermal range approaching upper tolerance limits (i.e. 12 -23•C; Poletto et al, 2017). Constraints on aerobic scope at elevated temperatures appear species specific.…”

Section: Thermal Independence Of Aerobic Scopementioning

confidence: 96%

“…For example, AAS can narrow at thermal extremes Nilsson et al, 2009;Johansen and Jones., 2011;Rummer et al, 2014), continually increase with rising temperature up to lethal limits (Norin et al, 2014), or be thermally independent (Ern et al, 2014;Verhille et al, 2016;Poletto et al, 2017). Likewise, the thermal plasticity of metabolism can differ within a species depending on level of assessment (i.e.…”

Section: Introductionmentioning

confidence: 99%

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DIVING IN A WARMING WORLD: Thermal constraints on the diving capacity of estuarine crocodiles (Crocodylus porosus)

Rodgers¹

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A central challenge in conserving biodiversity is predicting the consequences of anthropogenic climate change on species' distributions and persistence. Forced climate change has severely altered thermal regimes in marine and freshwater habitats. Rapid escalations in environmental temperatures may be particularly threatening to ectothermic species (almost all plants, invertebrates, fish, amphibians and reptiles), where body temperature and concomitant functional performance are strongly tied to the thermal environment. The threat of overheating is salient for air-breathing, ectothermic divers, such as the estuarine crocodile (Crocodylus porosus, Schneider, 1801), because submergence times are inversely related to water temperature. It is unknown how C. porosus will fare in warming waters but diving oxygen stores are hypothesised to be consumed more rapidly at elevated temperatures leading to a reduction of aerobic dive limits (i.e. maximum submergence time before lactate is accumulated). Shorter dive durations may force animals to spend more time at the water surface, leaving less time available for obligate underwater activities (e.g. predator avoidance and hunting for aquatic prey).This thesis assessed the effect of elevated water temperatures (emulating climate change scenarios) on the diving physiology and behaviour of C. porosus. The thermal sensitivity of predator avoidance dives (i.e. minutes submerged) was assessed in juveniles at three water temperatures reflecting climate change scenarios (Chapter 2). Diving performance was thermally sensitive with dive durations halving between the 'no warming' and 'moderate warming' scenarios. Ectotherms are however revered for their thermal acclimation/acclimatisation capacity following long term exposure to novel temperatures; whereby an animal's underlying physiology is responsively altered to maintain or optimise performance. For this reason, the acclimation capacity of C. porosus was assessed by exposing crocodiles to thermal acclimation treatments for a minimum of 30 days. Thermal acclimation treatments had no effect on dive durations -a result indicative of absent thermal acclimation capacity at elevated temperatures within 30 days.ii The physiological mechanisms underlying compromised diving performance at elevated temperatures were subsequently examined (Chapter 3). Reduced diving performance was hypothesised to be linked to increased oxygen demands and a reduced capacity for metabolic depression at elevated temperatures. Diving oxygen uptake, diving heart rate and post-dive plasma-lactate concentrations were assessed at two test temperatures (i.e. 28•C and 34•C). Diving metabolic rate increased threefold between 28•C and 34•C and the capacity to depress metabolic demands (from surface levels) was inhibited by 46%. Post-dive plasma-lactate accumulation was independent of water temperature. Collectively, these results show the aerobic dive limit of C. porosus was significantly reduced at elevated temperatures and animals behaviourally terminated dives...

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Unusual aerobic performance at high temperatures in juvenile Chinook salmon,Oncorhynchus tshawytscha

Abstract: Aerobic metabolic capacity was similar between juvenile Chinook salmon reared at 15 and 19°C and showed little change with acute warming to 23°C.

Cited by 47 publications

References 71 publications

Oxygen- and capacity-limited thermal tolerance: bridging ecology and physiology

Oxygen- and capacity-limited thermal tolerance: bridging ecology and physiology

Exploring key issues of aerobic scope interpretation in ectotherms: absolute versus factorial

DIVING IN A WARMING WORLD: Thermal constraints on the diving capacity of estuarine crocodiles (Crocodylus porosus)

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