Coping with a Warm Environment: Behavioral Thermoregulation by Lake Trout

Snucins, Ed; Gunn, John M.

doi:10.1577/1548-8659(1995)124<0118:cwaweb>2.3.co;2

Cited by 74 publications

(54 citation statements)

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“…By shifting from warm habitats (for example, aquatic = near-shore, terrestrial = direct sun) to cold refuge habitats (for example, aquatic = offshore, terrestrial = shade), organisms avoid detrimental and potentially lethal thermal exposure in their environment. Indeed, we found that the apex predator in these boreal lakes did, in fact, alter its habitat use in a manner expected by thermal tolerance (33,36), as we detected a decreased proportion of lake trout in near-shore habitat with relatively warmer air temperatures (Fig. 2D).…”

Section: Discussionmentioning

confidence: 64%

“…2D). Detailed field studies have previously found that lake trout behaviorally thermoregulate seeking coldwater refuges in the summer months (33,35,36). Despite a preference for cold water, summer tracking data have shown that lake trout occasionally take short forays into the littoral zone, in the summer, which is expected to be driven by the search for prey (35).…”

Section: Resultsmentioning

confidence: 99%

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Effects of differential habitat warming on complex communities

Tunney

McCann

Lester

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

116

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Food webs unfold across a mosaic of micro and macro habitats, with each habitat coupled by mobile consumers that behave in response to local environmental conditions. Despite this fundamental characteristic of nature, research on how climate change will affect whole ecosystems has overlooked (i) that climate warming will generally affect habitats differently and (ii) that mobile consumers may respond to this differential change in a manner that may fundamentally alter the energy pathways that sustain ecosystems. This reasoning suggests a powerful, but largely unexplored, avenue for studying the impacts of climate change on ecosystem functioning. Here, we use lake ecosystems to show that predictable behavioral adjustments to local temperature differentials govern a fundamental structural shift across 54 food webs. Data show that the trophic pathways from basal resources to a cold-adapted predator shift toward greater reliance on a cold-water refuge habitat, and food chain length increases, as air temperatures rise. Notably, cold-adapted predator behavior may substantially drive this decoupling effect across the climatic range in our study independent of warmer-adapted species responses (for example, changes in nearshore species abundance and predator absence). Such modifications reflect a flexible food web architecture that requires more attention from climate change research. The trophic pathway restructuring documented here is expected to alter biomass accumulation, through the regulation of energy fluxes to predators, and thus potentially threatens ecosystem sustainability in times of rapid environmental change.species interactions | thermoregulation | trophic structure | habitat coupling | heterogeneity N atural systems are inherently complex entities, wherein organisms act as agents of material and biomass transport (1) weaving food webs through a mosaic thermal environment. Direct temperature effects on trophic interactions arise through thermal regulation of an organism's physiology and behavior (2-5). For ecotherms (that is, organisms whose body temperature is aligned with ambient temperature), several biological rates show unimodal responses to temperature (2, 3, 6), and correspondingly, studies have shown that consumption rates initially rise with warming to a peak rate and then fall rapidly approaching a critical temperature (6). Understanding the ways that these organism responses alter food webs, and how these food web responses affect ecosystem function, are key requirements to predicting climate change impacts on ecosystems (7-11).A simple way to think about temperature's effects on any single trophic interaction is through the general linear consumption function:Consumptionðper capitaÞ = a t s R;[1]where a is the attack rate, t s is the time searching, and R is the resource biomass density. The direct effects of temperature on an organism's ability to encounter and capture resources in a given habitat may largely depend on a, and t s (with potential indirect effects relative to the consumer throug...

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Section: Discussionmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Effects of differential habitat warming on complex communities

Tunney

McCann

Lester

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

116

View full text Add to dashboard Cite

show abstract

“…Thermal refuges were described as critical habitats in a warming environment to explain summer movements and the spatial distribution of salmonids (Snucins and Gunn, 1995;Curry et al, 1997;Breau et al, 2011) or their diel movement patterns (Brewitt and Danner, 2014). Most studies on fish behavioural thermoregulation concern diel vertical or horizontal migration between warm and cool habitats, and these were interpreted as behaviours to maximize growth efficiency (Neverman and Wurtsbaugh, 1994;Armstrong et al, 2013) or as energy-saving strategies (Sims et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Heat transfer in fish: are short excursions between habitats a thermoregulatory behaviour to exploit resources in an unfavourable thermal environment?

Pépino

Goyer

Magnan

2015

Journal of Experimental Biology

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Temperature is the primary environmental factor affecting physiological processes in ectotherms. Heat-transfer models describe how the fish's internal temperature responds to a fluctuating thermal environment. Specifically, the rate coefficient (k), defined as the instantaneous rate of change in body temperature in relation to the difference between ambient and body temperature, summarizes the combined effects of direct thermal conduction through body mass, passive convection (intracellular and intercellular fluids) and forced convective heat transfer (cardiovascular system). The k-coefficient is widely used in fish ecology to understand how body temperature responds to changes in water temperature. The main objective of this study was to estimate the k-coefficient of brook charr equipped with internal temperaturesensitive transmitters in controlled laboratory experiments. Fish were first transferred from acclimation tanks (10°C) to tanks at 14, 19 or 23°C (warming experiments) and were then returned to the acclimation tanks (10°C; cooling experiments), thus producing six step changes in ambient temperature. We used non-linear mixed models to estimate the k-coefficient. Model comparisons indicated that the model incorporating the k-coefficient as a function of absolute temperature difference (dT: 4, 9 and 13°C) best described body temperature change. By simulating body temperature in a heterogeneous thermal environment, we provide theoretical predictions of maximum excursion duration between feeding and resting areas. Our simulations suggest that short (i.e. <60 min) excursions could be a common thermoregulatory behaviour adopted by cold freshwater fish species to sustain body temperature below a critical temperature threshold, enabling them to exploit resources in an unfavourable thermal environment.

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“…Associations between water temperature and salmonid distributions and behaviors have been relatively well-studied because of the species' commercial, recreational, and ecological importance. For example, resident adult trout are known to seek coolwater refugia in streams (Kaya et al 1977;Biro 1998;Baird and Krueger 2003) and lakes (Snucins and Gunn 1995). Adult anadromous salmonids can be temperature selective in the ocean (chum salmon O. keta; Tanaka et al 2000) and while holding in spawning and prespawning areas (Chinook salmon: Berman and Quinn 1991;Torgersen et al 1999;Newell and Quinn 2005;steelhead: Nielsen et al 1994).…”

Section: Discussionmentioning

confidence: 99%

Behavioral Thermoregulation and Slowed Migration by Adult Fall Chinook Salmon in Response to High Columbia River Water Temperatures

et al. 2006

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Abstract.-The relationships between lower Columbia River water temperatures and migration rates, temporary tributary use, and run timing of adult fall Chinook salmon Oncorhynchus tshawytscha were studied using historical counts at dams and recently collected radiotelemetry data. The results from more than 2,100 upriver bright fall Chinook salmon radio-tagged over 6 years (1998,(2000)(2001)(2002)(2003)(2004) showed that mean and median migration rates through the lower Columbia River slowed significantly when water temperatures were above about 208C. Slowed migration was strongly associated with temporary use of tributaries, which averaged 2-78C cooler than the main stem. The proportion of radio-tagged salmon using tributaries increased exponentially as Columbia River temperatures rose within the year, and use was highest in the warmest years. The historical passage data showed significant shifts in fall Chinook salmon run timing distributions concomitant with Columbia River warming and consistent with increasing use of thermal refugia. Collectively, these observations suggest that Columbia River fall Chinook salmon predictably alter their migration behaviors in response to elevated temperatures. Coolwater tributaries appear to represent critical habitat areas in warm years, and we recommend that both main-stem thermal characteristics and areas of refuge be considered when establishing regulations to protect summer and fall migrants.

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Coping with a Warm Environment: Behavioral Thermoregulation by Lake Trout

Cited by 74 publications

References 0 publications

Effects of differential habitat warming on complex communities

Effects of differential habitat warming on complex communities

Heat transfer in fish: are short excursions between habitats a thermoregulatory behaviour to exploit resources in an unfavourable thermal environment?

Behavioral Thermoregulation and Slowed Migration by Adult Fall Chinook Salmon in Response to High Columbia River Water Temperatures

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