Effects of hypoxia on scope-for-activity and power capacity of lake trout (<i>Salvelinus namaycush</i>)

Evans, Douglas E.

doi:10.1139/f07-007

Cited by 90 publications

(83 citation statements)

References 66 publications

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“…However, if reduced enough it will affect all aspects of the individual's performance as less energy can be devoted to feeding, growth and reproduction (Fry, 1947;Nilsson et al, 2009). In salmonids it has been suggested that at least 60-75% of the aerobic scope is required to avoid daily metabolic constraints and increased risk of mortality (Priede, 1977;Priede, 1985;Evans, 2007). It may be inferred from the lower susceptibility of P. leniusculus to SS that this invader would suffer less reduction in fitness and is therefore likely to be more successful than native A. pallipes in anthropogenically impacted environments such as those with high SS loadings.…”

Section: Discussionmentioning

confidence: 99%

Muddied waters: suspended sediment impacts on gill structure and aerobic scope in an endangered native and an invasive freshwater crayfish

et al. 2013

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Suspended sediment (SS) loadings in freshwater habitats have increased over the past century and SS is now a significant environmental stressor. Greater tolerance to environmental stressors has been proposed as a factor in the success of aquatic invasive species. Further, parasites may interact with environmental stressors to increase host susceptibility to loss of fitness and mortality. We compared the effects of SS exposure on the gill structure and aerobic scope of the endangered white-clawed crayfish (Austropotamobius pallipes), and the invasive signal crayfish (Pacifastacus leniusculus), and assessed impacts in relation to parasite burden. SS caused gill fouling and reduction in aerobic scope in both species, though A. pallipes was more susceptible than invasive P. leniusculus. The parasite Branchiobdella astaci, a crayfish worm that infests the gills, interacted with the sediment to affect gill structure whereas infection with the microsporidian parasite Thelohania contejeani had no effect on crayfish response to SS. Juvenile P. lenisuculus had a higher standard metabolic rate than A. pallipes, which may be linked to competitive advantages such as higher growth rate and behavioural dominance. Conservation of A. pallipes often involves relocation of threatened populations to isolated stillwaters; our findings suggest that SS levels should be assessed before relocation.

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Section: Discussionmentioning

confidence: 99%

Muddied waters: suspended sediment impacts on gill structure and aerobic scope in an endangered native and an invasive freshwater crayfish

et al. 2013

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“…Because lake trout spawn inshore in the fall (40), we were unable to distinguish between foraging and spawning behavior. By using the date when littoral water temperatures exceeded 15°C, we provide a measure of how access to littoral energy is controlled by temperature (19,41). We did not use the existence of a planar thermocline to define summer, because this can occur when littoral temperatures are ≤15°C and would not represent a physiological barrier for lake trout (41).…”

Section: Methodsmentioning

confidence: 99%

Behavioral responses to annual temperature variation alter the dominant energy pathway, growth, and condition of a cold-water predator

Guzzo

Blanchfield

Rennie

2017

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

111

139

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There is a pressing need to understand how ecosystems will respond to climate change. To date, no long-term empirical studies have confirmed that fish populations exhibit adaptive foraging behavior in response to temperature variation and the potential implications this has on fitness. Here, we use an unparalleled 11-y acoustic telemetry, stable isotope, and mark-recapture dataset to test if a population of lake trout (Salvelinus namaycush), a coldwater stenotherm, adjusted its use of habitat and energy sources in response to annual variations in lake temperatures during the open-water season and how these changes translated to the growth and condition of individual fish. We found that climate influenced access to littoral regions in spring (data from telemetry), which in turn influenced energy acquisition (data from isotopes), and growth (mark-recapture data). In more stressful years, those with shorter springs and longer summers, lake trout had reduced access to littoral habitat and assimilated less littoral energy, resulting in reduced growth and condition. Annual variation in prey abundance influenced lake trout foraging tactics (i.e., the balance of the number and duration of forays) but not the overall time spent in littoral regions. Lake trout greatly reduced their use of littoral habitat and occupied deep pelagic waters during the summer. Together, our results provide clear evidence that climate-mediated behavior can influence the dominant energy pathways of top predators, with implications ranging from individual fitness to food web stability.food web | climate change | habitat coupling | lake trout | north-temperate lake T here is growing urgency to understand how ecosystems are responding to climate change (1, 2). Recent work, using latitudinal gradients as proxies to warming, has argued that the behavioral responses of mobile top predators to changing temperatures can drive fundamental shifts in aquatic food webs by altering the coupling of major energy pathways (3, 4). Although this work is intriguing, no one has yet examined long-term empirical data that have explicitly tested if populations of top predators can shift their foraging behavior in response to annual changes in temperature or has evaluated what implications this might have for individual fitness. Temporal studies are critically important in this context because they control for the ecosystemspecific adaptations that can confound latitudinal studies and instead focus on the active responses to changing conditions that are highly relevant to understanding the impacts of climate change.Mobile top predators display adaptive foraging behavior by moving across spatially disparate habitats in response to changing conditions, most notably prey densities. For example, birds feed on both terrestrial and aquatic prey, effectively coupling these ecosystems (5). Habitat coupling can also occur within ecosystems and has been well described in freshwater lakes, where predatory fish feed upon prey supported by dissimilar energy sources, such as offsho...

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“…(i) the lake stratifies in summer, does not exhibit hypolimnetic oxygen depletion during stratification and thus provides a coldwater summer refuge to sustain the population (Evans 2007;Blanchfield et al 2009); (ii) the lake does not stratify, but surface temperatures do not reach lethal levels and the fish is free of competitors with higher preferred temperatures (Gunn 2002;Mackenzie-Grieve and Post 2006).…”

Section: Winter Strategies Overwhelmed: the Location Of Zoogeographicmentioning

confidence: 99%

The role of winter phenology in shaping the ecology of freshwater fish and their sensitivities to climate change

et al. 2012

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Thermal preference and performance provide the physiological frame within which fish species seek strategies to cope with the challenges raised by the low temperatures and low levels of oxygen and food that characterize winter. There are two common coping strategies: active utilization of winter conditions or simple toleration of winter conditions. The former is typical of winter specialist species with low preferred temperatures, and the latter is typical of species with higher preferred temperatures. Reproductive strategies are embodied in the phenology of spawning: the approach of winter conditions cues reproductive activity in many coldwater fish species, while the departure of winter conditions cues reproduction in many cool and warmwater fish species. This cuing system promotes temporal partitioning of the food resources available to young-of-year fish and thus supports high diversity in freshwater fish communities. If the zoogeographic distribution of a species covers a broad range of winter conditions, local populations may exhibit differences in their winter survival strategies that reflect adaptation to local conditions. Extreme winter specialists are found in shallow eutrophic lakes where long periods of ice cover cause winter oxygen levels to drop to levels that are lethal to many fish. The fish communities of these lakes are simple and composed of species that exhibit specialized adaptations for extended tolerance of very low temperatures and oxygen levels. Zoogeographic boundaries for some species may be positioned at points on the landscape where the severity of winter overwhelms the species' repertoire of winter survival strategies. Freshwater fish communities are vulnerable to many of the shifts in environmental conditions expected with climate change. Temperate and northern communities are particularly vulnerable since the repertoires of physiological and behavioural strategies that characterize many of their members have been shaped by the adverse environmental conditions (e.g. cool short summers, long cold winters) that climate change is expected to mitigate. The responses of these strategies to the rapid relaxation of the adversities that shaped them will play a significant role in the overall responses of these fish populations and their communities to climate change.

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Effects of hypoxia on scope-for-activity and power capacity of lake trout (Salvelinus namaycush)

Cited by 90 publications

References 66 publications

Muddied waters: suspended sediment impacts on gill structure and aerobic scope in an endangered native and an invasive freshwater crayfish

Muddied waters: suspended sediment impacts on gill structure and aerobic scope in an endangered native and an invasive freshwater crayfish

Behavioral responses to annual temperature variation alter the dominant energy pathway, growth, and condition of a cold-water predator

The role of winter phenology in shaping the ecology of freshwater fish and their sensitivities to climate change

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