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Ziegler AF, Bluhm BA, Renaud PE, Jørgensen LL. Isotopic turnover in polar cod (Boreogadus saida) muscle determined through a controlled feeding experiment. JOURNAL OF FISH BIOLOGY 2023; 102:1442-1454. [PMID: 36999199 DOI: 10.1111/jfb.15389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 03/29/2023] [Indexed: 06/09/2023]
Abstract
Polar cod (Boreogadus saida) is an important trophic link within Arctic marine food webs and is likely to experience diet shifts in response to climate change. One important tool for assessing organism diet is bulk stable isotope analysis. However, key parameters necessary for interpreting the temporal context of stable isotope values are lacking, especially for Arctic species. This study provides the first experimental determination of isotopic turnover (as half-life) and trophic discrimination factors (TDFs) of both δ13 C and δ15 N in adult polar cod muscle. Using a diet enriched in both 13 C and 15 N, we measured isotopic turnover times of 61 and 49 days for δ13 C and δ15 N, respectively, with metabolism accounting for >94% of the total turnover. These half-life estimates are valid for adult polar cod (>3 years) experiencing little somatic growth. We measured TDFs in our control of 2.6‰ and 3.9‰ for δ13 C and δ15 N, respectively, and we conclude that applying the commonly used TDF of ~1‰ for δ13 C for adult polar cod may lead to misrepresentation of dietary carbon source, while the use of 3.8‰ for δ15 N is appropriate. Based on these results, we recommend that studies investigating seasonal shifts in the diet of adult polar cod sample at temporal intervals of at least 60 days to account for isotopic turnover in polar cod muscle. Although isotopic equilibrium was reached by the fish in this study, it was at substantially lower isotope values than the diet. Additionally, the use of highly enriched algae in the experimental feed caused very high variability in diet isotope values which precluded accurate calculation of TDFs from the enriched fish. As a result of the challenges faced in this study, we discourage the use of highly enriched diets for similar experiments and provide recommendations to guide the design of future isotopic turnover experiments.
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Affiliation(s)
- Amanda Fern Ziegler
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- Institute of Marine Research, Fram Centre, Tromsø, Norway
| | - Bodil A Bluhm
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Paul E Renaud
- Akvaplan-niva, Fram Centre for Climate and the Environment, Tromsø, Norway
- University Centre in Svalbard, Longyearbyen, Norway
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2
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Distinct genetic clustering in the weakly differentiated polar cod, Boreogadus saida Lepechin, 1774 from East Siberian Sea to Svalbard. Polar Biol 2021. [DOI: 10.1007/s00300-021-02911-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AbstractThe cold-adapted polar cod Boreogadus saida, a key species in Arctic ecosystems, is vulnerable to global warming and ice retreat. In this study, 1257 individuals sampled in 17 locations within the latitudinal range of 75–81°N from Svalbard to East Siberian Sea were genotyped with a dedicated suite of 116 single-nucleotide polymorphic loci (SNP). The overall pattern of isolation by distance (IBD) found was driven by the two easternmost samples (East Siberian Sea and Laptev Sea), whereas no differentiation was registered in the area between the Kara Sea and Svalbard. Eleven SNP under strong linkage disequilibrium, nine of which could be annotated to chromosome 2 in Atlantic cod, defined two genetic groups of distinct size, with the major cluster containing seven-fold larger number of individuals than the minor. No underlying geographic basis was evident, as both clusters were detected throughout all sampling sites in relatively similar proportions (i.e. individuals in the minor cluster ranging between 4 and 19% on the location basis). Similarly, females and males were also evenly distributed between clusters and age groups. A differentiation was, however, found regarding size at age: individuals belonging to the major cluster were significantly longer in the second year. This study contributes to increasing the population genetic knowledge of this species and suggests that an appropriate management should be ensured to safeguard its diversity.
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3
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Varying heat tolerance among Arctic nearshore fishes. Polar Biol 2021. [DOI: 10.1007/s00300-021-02815-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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4
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Lefevre S, Wang T, McKenzie DJ. The role of mechanistic physiology in investigating impacts of global warming on fishes. J Exp Biol 2021; 224:224/Suppl_1/jeb238840. [PMID: 33627469 DOI: 10.1242/jeb.238840] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Warming of aquatic environments as a result of climate change is already having measurable impacts on fishes, manifested as changes in phenology, range shifts and reductions in body size. Understanding the physiological mechanisms underlying these seemingly universal patterns is crucial if we are to reliably predict the fate of fish populations with future warming. This includes an understanding of mechanisms for acute thermal tolerance, as extreme heatwaves may be a major driver of observed effects. The hypothesis of gill oxygen limitation (GOL) is claimed to explain asymptotic fish growth, and why some fish species are decreasing in size with warming; but its underlying assumptions conflict with established knowledge and direct mechanistic evidence is lacking. The hypothesis of oxygen- and capacity-limited thermal tolerance (OCLTT) has stimulated a wave of research into the role of oxygen supply capacity and thermal performance curves for aerobic scope, but results vary greatly between species, indicating that it is unlikely to be a universal mechanism. As thermal performance curves remain important for incorporating physiological tolerance into models, we discuss potentially fruitful alternatives to aerobic scope, notably specific dynamic action and growth rate. We consider the limitations of estimating acute thermal tolerance by a single rapid measure whose mechanism of action is not known. We emphasise the continued importance of experimental physiology, particularly in advancing our understanding of underlying mechanisms, but also the challenge of making this knowledge relevant to the more complex reality.
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Affiliation(s)
- Sjannie Lefevre
- Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Tobias Wang
- Department of Biology - Zoophysiology, Aarhus University, 8000 Aarhus C, Denmark
| | - David J McKenzie
- Marine Biodiversity, Exploitation and Conservation (MARBEC), Université de Montpellier, CNRS, Ifremer, IRD, 34000 Montpellier, France
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5
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Johansen JL, Nadler LE, Habary A, Bowden AJ, Rummer J. Thermal acclimation of tropical coral reef fishes to global heat waves. eLife 2021; 10:59162. [PMID: 33496262 PMCID: PMC7837695 DOI: 10.7554/elife.59162] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 01/05/2021] [Indexed: 02/06/2023] Open
Abstract
As climate-driven heat waves become more frequent and intense, there is increasing urgency to understand how thermally sensitive species are responding. Acute heating events lasting days to months may elicit acclimation responses to improve performance and survival. However, the coordination of acclimation responses remains largely unknown for most stenothermal species. We documented the chronology of 18 metabolic and cardiorespiratory changes that occur in the gills, blood, spleen, and muscles when tropical coral reef fishes are thermally stressed (+3.0°C above ambient). Using representative coral reef fishes (Caesio cuning and Cheilodipterus quinquelineatus) separated by >100 million years of evolution and with stark differences in major life-history characteristics (i.e. lifespan, habitat use, mobility, etc.), we show that exposure duration illicited coordinated responses in 13 tissue and organ systems over 5 weeks. The onset and duration of biomarker responses differed between species, with C. cuning – an active, mobile species – initiating acclimation responses to unavoidable thermal stress within the first week of heat exposure; conversely, C. quinquelineatus – a sessile, territorial species – exhibited comparatively reduced acclimation responses that were delayed through time. Seven biomarkers, including red muscle citrate synthase and lactate dehydrogenase activities, blood glucose and hemoglobin concentrations, spleen somatic index, and gill lamellar perimeter and width, proved critical in evaluating acclimation progression and completion, as these provided consistent evaluation of thermal responses across species.
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Affiliation(s)
- Jacob L Johansen
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, United States.,ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia
| | - Lauren E Nadler
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia.,Halmos College of Arts and Sciences, Nova Southeastern University, Dania Beach, United States.,College of Science and Engineering, James Cook University, Townsville, Australia
| | - Adam Habary
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia
| | - Alyssa J Bowden
- CSIRO, Hobart, Australia.,Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Jodie Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia.,College of Science and Engineering, James Cook University, Townsville, Australia
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6
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Gilbert MJH, Farrell AP. The thermal acclimation potential of maximum heart rate and cardiac heat tolerance in Arctic char (Salvelinus alpinus), a northern cold-water specialist. J Therm Biol 2020; 95:102816. [PMID: 33454044 DOI: 10.1016/j.jtherbio.2020.102816] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/30/2020] [Accepted: 12/12/2020] [Indexed: 10/22/2022]
Abstract
Increasing heart rate (ƒH) is a central, if not primary mechanism used by fishes to support their elevated tissue oxygen consumption during acute warming. Thermal acclimation can adjust this acute response to improve cardiac performance and heat tolerance under the prevailing temperatures. We predict that such acclimation will be particularly important in regions undergoing rapid environmental change such as the Arctic. Therefore, we acclimated Arctic char (Salvelinus alpinus), a high latitude, cold-adapted salmonid, to ecologically relevant temperatures (2, 6, 10, 14 and 18 °C) and examined how thermal acclimation influenced their cardiac heat tolerance by measuring the maximum heart rate (ƒHmax) response to acute warming. As expected, acute warming increased ƒHmax in all Arctic char before ƒHmax reached a peak and then became arrhythmic. The peak ƒHmax, and the temperature at which peak ƒHmax (Tpeak) and that at which arrhythmia first occurred (Tarr) all increased progressively (+33%, 49% and 35%, respectively) with acclimation temperature from 2 to 14 °C. When compared at the same test temperature ƒHmax also decreased by as much as 29% with increasing acclimation temperature, indicating significant thermal compensation. The upper temperature at which fish first lost their equilibrium (critical thermal maximum: CTmax) also increased with acclimation temperature, albeit to a lesser extent (+11%). Importantly, Arctic char experienced mortality after several weeks of acclimation at 18 °C and survivors did not have elevated cardiac thermal tolerance. Collectively, these findings suggest that if wild Arctic char have access to suitable temperatures (<18 °C) for a sufficient duration, warm acclimation can potentially mitigate some of the cardiorespiratory impairments previously documented during acute heat exposure.
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Affiliation(s)
- Matthew J H Gilbert
- Department of Zoology, University of British Columbia, #4200 - 6270, University Blvd, Vancouver, BC, V6T 1Z4, Canada.
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, #4200 - 6270, University Blvd, Vancouver, BC, V6T 1Z4, Canada; Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, V6T 1Z4, Canada
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7
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Little AG, Loughland I, Seebacher F. What do warming waters mean for fish physiology and fisheries? JOURNAL OF FISH BIOLOGY 2020; 97:328-340. [PMID: 32441327 DOI: 10.1111/jfb.14402] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/30/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Environmental signals act primarily on physiological systems, which then influence higher-level functions such as movement patterns and population dynamics. Increases in average temperature and temperature variability associated with global climate change are likely to have strong effects on fish physiology and thereby on populations and fisheries. Here we review the principal mechanisms that transduce temperature signals and the physiological responses to those signals in fish. Temperature has a direct, thermodynamic effect on biochemical reaction rates. Nonetheless, plastic responses to longer-term thermal signals mean that fishes can modulate their acute thermal responses to compensate at least partially for thermodynamic effects. Energetics are particularly relevant for growth and movement, and therefore for fisheries, and temperature can have pronounced effects on energy metabolism. All energy (ATP) production is ultimately linked to mitochondria, and temperature has pronounced effects on mitochondrial efficiency and maximal capacities. Mitochondria are dependent on oxygen as the ultimate electron acceptor so that cardiovascular function and oxygen delivery link environmental inputs with energy metabolism. Growth efficiency, that is the conversion of food into tissue, changes with temperature, and there are indications that warmer water leads to decreased conversion efficiencies. Moreover, movement and migration of fish relies on muscle function, which is partially dependent on ATP production but also on intracellular calcium cycling within the myocyte. Neuroendocrine processes link environmental signals to regulated responses at the level of different tissues, including muscle. These physiological processes within individuals can scale up to population responses to climate change. A mechanistic understanding of thermal responses is essential to predict the vulnerability of species and populations to climate change.
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Affiliation(s)
| | - Isabella Loughland
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
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9
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Gilbert MJH, Harris LN, Malley BK, Schimnowski A, Moore JS, Farrell AP. The thermal limits of cardiorespiratory performance in anadromous Arctic char ( Salvelinus alpinus): a field-based investigation using a remote mobile laboratory. CONSERVATION PHYSIOLOGY 2020; 8:coaa036. [PMID: 32346481 PMCID: PMC7176916 DOI: 10.1093/conphys/coaa036] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 05/31/2023]
Abstract
Despite immense concern over amplified warming in the Arctic, physiological research to address related conservation issues for valuable cold-adapted fish, such as the Arctic char (Salvelinus alpinus), is lacking. This crucial knowledge gap is largely attributable to the practical and logistical challenges of conducting sensitive physiological investigations in remote field settings. Here, we used an innovative, mobile aquatic-research laboratory to assess the effects of temperature on aerobic metabolism and maximum heart rate (f Hmax) of upriver migrating Arctic char in the Kitikmeot region of Nunavut in the central Canadian Arctic. Absolute aerobic scope was unchanged at temperatures from 4 to 16°C, while f Hmax increased with temperature (Q 10 = 2.1), as expected. However, f Hmax fell precipitously below 4°C and it began to plateau above ~ 16°C, reaching a maximum at ~ 19°C before declining and becoming arrhythmic at ~ 21°C. Furthermore, recovery from exhaustive exercise appeared to be critically impaired above 16°C. The broad thermal range (~4-16°C) for increasing f Hmax and maintaining absolute aerobic scope matches river temperatures commonly encountered by migrating Arctic char in this region. Nevertheless, river temperatures can exceed 20°C during warm events and our results confirm that such temperatures would limit exercise performance and thus impair migration in this species. Thus, unless Arctic char can rapidly acclimatize or alter its migration timing or location, which are both open questions, these impairments would likely impact population persistence and reduce lifetime fitness. As such, future conservation efforts should work towards quantifying and accounting for the impacts of warming, variable river temperatures on migration and reproductive success.
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Affiliation(s)
- Matthew J H Gilbert
- Department of Zoology, University of British Columbia, #4200-6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
| | - Les N Harris
- Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB, R3T 2N6, Canada
| | - Brendan K Malley
- Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB, R3T 2N6, Canada
| | - Adrian Schimnowski
- Arctic Research Foundation, 1505 Charleswood Road, Winnipeg, MB, R3S 1C2, Canada
| | - Jean-Sébastien Moore
- Institut de Biologie Intégrative et des Systèmes and Département de Biologie, Université Laval, 1030 Avenue de la Médecine, Quebec City, QC, Québec G1V 0A6, Canada
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, #4200-6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
- Faculty of Land and Food Systems, University of British Columbia, #4200-6270 University Blvd, Vancouver, BC, V6T 1Z4
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10
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Abstract
AbstractThe polar cod (Boreogadus saida) in the Barents Sea is one of the main stocks of this species in the Arctic, reaching a total biomass of almost 2 million tonnes in some years. It has been fluctuating considerably in abundance, and in recent years, it has been at a low level. Only small catches have been taken from the stock over the last four decades, and consequently, the observed variation in abundance must be caused by natural (environmental and/or biological) changes in the ecosystem. Sea temperatures have been rising in the Barents Sea in recent years, possibly causing changes to the living conditions of this true Arctic stock. Consequently, there is a need for investigating how the observed changes might affect polar cod in this area. One important aspect of the environmental impact on the stock is possible effect on the recruitment, which has been varying considerably from year to year. In this modelling study, we thus recreate and analyse the environmental and developmental histories of the observed 0-group individuals in the Barents Sea (young of the year), with emphasis on the importance of ice cover, ice breakup time, maximum temperature, and spawning stock biomass. Our simulations indicate that the environmental conditions experienced by individuals successfully “recruited” to the 0-group are characterized by high ice concentration well into summer, and low temperatures throughout the pelagic juvenile phase, and any perturbations from the Arctic ocean climate typically found in the northern and eastern Barents Sea appears to be detrimental to stock recruitment. In light of the projected warming of the Barents Sea in the next decades and the potential reduction in ice cover, this will entail, the mechanisms investigated herein might lead to future marginalization of polar cod in the Barents Sea.
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11
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Safi H, Zhang Y, Schulte PM, Farrell AP. The effect of acute warming and thermal acclimation on maximum heart rate of the common killifish Fundulus heteroclitus. JOURNAL OF FISH BIOLOGY 2019; 95:1441-1446. [PMID: 31613985 DOI: 10.1111/jfb.14159] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Common killifish Fundulus heteroclitus were acclimated to ecologically relevant temperatures (5, 15 and 33°C) and their maximum heart rate (fHmax ) was measured at each acclimation temperature during an acute warming protocol. Acclimation to 33°C increased peak fHmax by up to 32% and allowed the heart to beat rhythmically at a temperature 10°C higher when compared with acclimation to 5°C. Independent of acclimation temperature, peak fHmax occurred about 3°C cooler than the temperature that first produced cardiac arrhythmias. Thus, when compared with previously published values for the critical thermal maximum of F. heteroclitus, the temperature for peak fHmax was cooler and the temperature that first produced cardiac arrhythmias was similar to these critical thermal maxima. The considerable thermal plasticity of fHmax demonstrated in the present study is entirely consistent with eurythermal ecology of killifish, as shown previously for another eurythermal fish Gillichthys mirabilis.
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Affiliation(s)
- Hamid Safi
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yangfan Zhang
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
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12
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Hassinen M, Korajoki H, Abramochkin D, Krivosheya P, Vornanen M. Transcript expression of inward rectifier potassium channels of Kir2 subfamily in Arctic marine and freshwater fish species. J Comp Physiol B 2019; 189:735-749. [PMID: 31679058 DOI: 10.1007/s00360-019-01241-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/30/2019] [Accepted: 10/16/2019] [Indexed: 02/08/2023]
Abstract
Inward rectifier K+ (Kir2) channels are critical for electrical excitability of cardiac myocytes. Here, we examine expression of Kir2 channels in the heart of three Gadiformes species, polar cod (Boreogadus saida) and navaga (Eleginus nawaga) of the Arctic Ocean and burbot (Lota lota) of the temperate lakes to find out the role of Kir2 channels in cardiac adaptation to cold. Five boreal freshwater species: brown trout (Salmo trutta fario), arctic char (Salvelinus alpinus), roach (Rutilus rutilus), perch (Perca fluviatilis) and pike (Esox lucius), and zebrafish (Danio rerio), were included for comparison. Transcript expression of genes encoding Kir2.1a, - 2.1b, - 2.2a, - 2.2b and - 2.4 was studied from atrium and ventricle of thermally acclimated or acclimatized fish by quantitative PCR. Kir2 composition in the polar cod was more diverse than in other species in that all Kir2 isoforms were relatively highly expressed. Kir2 composition of navaga and burbot differed from that of the polar cod as well as from those of other species. The relative expression of Kir2.2 transcripts, especially Kir2.2b, was higher in both atrium and ventricle of navaga and burbot (56-89% from the total Kir2 pool) than in other species (0.1-11%). Thermal acclimation induced only small changes in cardiac Kir2 transcript expression in Gadiformes species. However, Kir2.2b transcripts were upregulated in cold-acclimated navaga and burbot hearts. All in all, the cardiac Kir2 composition seems to be dependent on both phylogenetic position and thermal preference of the fish.
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Affiliation(s)
- Minna Hassinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland.
| | - Hanna Korajoki
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland
| | - Denis Abramochkin
- Department of Human and Animal Physiology, Moscow State University, Leninskiye Gory, 1, 12, Moscow, 119991, Russia.,Ural Federal University, Mira 19, Ekaterinburg, 620002, Russia.,Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Pavel Krivosheya
- Russian Federal Research Institute of Fisheries and Oceanography "VNIRO" Polar Branch of VNIRO, Laboratory of pelagic fish, Akademika Knipovicha st., Murmansk, 183038, Russia, Murmansk, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland
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13
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Marchant JL, Farrell AP. Membrane and calcium clock mechanisms contribute variably as a function of temperature to setting cardiac pacemaker rate in zebrafish Danio rerio. JOURNAL OF FISH BIOLOGY 2019; 95:1265-1274. [PMID: 31429079 DOI: 10.1111/jfb.14126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/19/2019] [Indexed: 06/10/2023]
Abstract
Here, we show that heart rate in zebrafish Danio rerio is dependent upon two pacemaking mechanisms and it possesses a limited ability to reset the cardiac pacemaker with temperature acclimation. Electrocardiogram recordings, taken from individual, anaesthetised zebrafish that had been acclimated to 18, 23 or 28°C were used to follow the response of maximum heart rate (fHmax ) to acute warming from 18°C until signs of cardiac failure appeared (up to c. 40°C). Because fHmax was similar across the acclimation groups at almost all equivalent test temperatures, warm acclimation was limited to one significant effect, the 23°C acclimated zebrafish had a significantly higher (21%) peak fHmax and reached a higher (3°C) test temperature than the 18°C acclimated zebrafish. Using zatebradine to block the membrane hyperpolarisation-activated cyclic nucleotide-gated channels (HCN) and examine the contribution of the membrane clock mechanisms to cardiac pacemaking, f Hmax was significantly reduced (by at least 40%) at all acute test temperatures and significantly more so at most test temperatures for zebrafish acclimated to 28°C vs. 23°C. Thus, HCN channels and the membrane clock were not only important, but could be modified by thermal acclimation. Using a combination of ryanodine (to block sarcoplasmic calcium release) and thapsigargin (to block sarcoplasmic calcium reuptake) to examine the contribution of sarcoplasmic reticular handling of calcium and the calcium clock, f Hmax was again consistently reduced independent of the test temperature and acclimation temperature, but to a significantly lesser degree than zatebradine for zebrafish acclimated to both 28 and 18°C. Thus, the calcium clock mechanism plays an additional role in setting pacemaker activity that was independent of temperature. In conclusion, the zebrafish cardiac pacemaker has a limited temperature acclimation ability compared with known effects for other fishes and involves two pacemaking mechanisms, one of which was independent of temperature.
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Affiliation(s)
- James L Marchant
- Zoology Department, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anthony P Farrell
- Zoology Department, University of British Columbia, Vancouver, British Columbia, Canada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
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14
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Rohr JR, Civitello DJ, Cohen JM, Roznik EA, Sinervo B, Dell AI. Different metrics of thermal acclimation yield similar effects of latitude, acclimation duration, and body mass on acclimation capacities. GLOBAL CHANGE BIOLOGY 2019; 25:e3-e4. [PMID: 30983105 DOI: 10.1111/gcb.14653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 02/24/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, University of Notre Dame, Notre Dame, Indiana
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | | | - Jeremy M Cohen
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | - Elizabeth A Roznik
- Memphis Zoo, Department of Research and Conservation, Memphis, Tennessee
| | - Barry Sinervo
- Department of Ecology and Evolutionary Biology, University of California at Santa Cruz, Santa Cruz, California
| | - Anthony I Dell
- National Great Rivers Research and Education Centre (NGRREC), Alton, Illinois
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri
- Department of Biology, St. Louis University, St. Louis, Missouri
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15
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Gilbert MJH, Rani V, McKenzie SM, Farrell AP. Autonomic cardiac regulation facilitates acute heat tolerance in rainbow trout: in situ and in vivo support. ACTA ACUST UNITED AC 2019; 222:jeb.194365. [PMID: 31015284 DOI: 10.1242/jeb.194365] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/10/2019] [Indexed: 12/27/2022]
Abstract
Acute warming in fish increases heart rate (f H) and cardiac output to peak values, after which performance plateaus or declines and arrhythmia may occur. This cardiac response can place a convective limitation on systemic oxygen delivery at high temperatures. To test the hypothesis that autonomic cardiac regulation protects cardiac performance in rainbow trout during acute warming, we investigated adrenergic and cholinergic regulation during the onset and progression of cardiac limitations. We explored the direct effects of adrenergic stimulation by acutely warming an in situ working perfused heart until arrhythmia occurred, cooling the heart to restore rhythmicity and rewarming with increasing adrenergic stimulation. Adrenergic stimulation produced a clear, dose-dependent increase in the temperature and peak f H achieved prior to the onset of arrhythmia. To examine how this adrenergic protection functions in conjunction with cholinergic vagal inhibition in vivo, rainbow trout fitted with ECG electrodes were acutely warmed in a respirometer until they lost equilibrium (CTmax) with and without muscarinic (atropine) and β-adrenergic (sotalol) antagonists. Trout exhibited roughly equal and opposing cholinergic and adrenergic tone on f H that persisted up to critical temperatures. β-Adrenergic blockade significantly lowered peak f H by 14-17%, while muscarinic blockade significantly lowered the temperature for peak f H by 2.0°C. Moreover, muscarinic and β-adrenergic blockers injected individually or together significantly reduced CTmax by up to 3°C, indicating for the first time that cardiac adrenergic stimulation and cholinergic inhibition can enhance acute heat tolerance in rainbow trout at the level of the heart and the whole animal.
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Affiliation(s)
- Matthew J H Gilbert
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Varsha Rani
- Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Sean M McKenzie
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.,Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
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16
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Abramochkin DV, Haverinen J, Mitenkov YA, Vornanen M. Temperature- and external K+-dependence of electrical excitation in ventricular myocytes of cod-like fishes. J Exp Biol 2019; 222:jeb.193607. [DOI: 10.1242/jeb.193607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/16/2019] [Indexed: 01/08/2023]
Abstract
Electrical excitability (EE) is vital for cardiac function and strongly modulated by temperature and external K+ concentration ([K+]o) as formulated in the hypothesis of temperature-dependent deterioration of electrical excitability (TDEE). Since little is known about EE of arctic stenothermic fishes, we tested the TDEE hypothesis on ventricular myocytes of polar cod (Boreogadus saida) and navaga cod (Eleginus navaga) of the Arctic Ocean and those of temperate freshwater burbot (Lota lota). Ventricular action potentials (APs) were elicited in current-clamp experiments at 3, 9 and 15°C, and AP characteristics and the current needed to elicit AP were examined. At 3°C, ventricular APs of polar and navaga cod were similar but differed from that of burbot in having lower rate of AP upstroke and higher rate of repolarization. EE of ventricular myocytes - defined as the ease with which all-or-none APs are triggered - was little affected by acute temperature changes between 3 and 15°C in any species. However, AP duration (APD50) was drastically reduced at higher temperatures. Elevation of [K+]o from 3 to 5.4 and further to 8 mM at 3, 9 and 15°C strongly affected EE and AP characteristics in polar and navaga cod, but less in burbot. In all species, ventricular excitation was resistant to acute temperature elevations, while small increases in [K+]o severely compromised EE, in particular in the marine stenotherms. This suggests that EE of the heart in these Gadiformes species is well equipped against acute warming, but less so against the simultaneous temperature and exercise stresses.
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Affiliation(s)
- Denis V. Abramochkin
- Department of human and animal physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russia
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Jaakko Haverinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| | - Yuri A. Mitenkov
- VNIRO Russian Federal Research Institute of Fisheries and Oceanography, Moscow, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
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17
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Kunz KL, Claireaux G, Pörtner HO, Knust R, Mark FC. Aerobic capacities and swimming performance of polar cod ( Boreogadus saida) under ocean acidification and warming conditions. J Exp Biol 2018; 221:jeb184473. [PMID: 30190318 PMCID: PMC6240293 DOI: 10.1242/jeb.184473] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/01/2018] [Indexed: 01/09/2023]
Abstract
Polar cod (Boreogadus saida) is an important prey species in the Arctic ecosystem, yet its habitat is changing rapidly: climate change, through rising seawater temperatures and CO2 concentrations, is projected to be most pronounced in Arctic waters. This study aimed to investigate the influence of ocean acidification and warming on maximum performance parameters of B. saida as indicators for the species' acclimation capacities under environmental conditions projected for the end of this century. After 4 months at four acclimation temperatures (0, 3, 6, 8°C) each combined with two PCO2 levels (390 and 1170 µatm), aerobic capacities and swimming performance of B. saida were recorded following a Ucrit protocol. At both CO2 levels, standard metabolic rate (SMR) was elevated at the highest acclimation temperature indicating thermal limitations. Maximum metabolic rate (MMR) increased continuously with temperature, suggesting an optimum temperature for aerobic scope for exercise (ASex) at 6°C. Aerobic swimming performance (Ugait) increased with acclimation temperature irrespective of CO2 levels, while critical swimming speed (Ucrit) did not reveal any clear trend with temperature. Hypercapnia evoked an increase in MMR (and thereby ASex). However, swimming performance (both Ugait and Ucrit) was impaired under elevated near-future PCO2 conditions, indicating reduced efficiencies of oxygen turnover. The contribution of anaerobic metabolism to swimming performance was very low overall, and further reduced under hypercapnia. Our results revealed high sensitivities of maximum performance parameters (MMR, Ugait, Ucrit) of B. saida to ocean acidification. Impaired swimming capacity under ocean acidification may reflect reduced future competitive strength of B. saida.
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Affiliation(s)
- Kristina Lore Kunz
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bentho-Pelagic Processes, Am Alten Hafen 26, 27568 Bremerhaven, Germany
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany
- University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, 28359 Bremen, Germany
| | - Guy Claireaux
- Université de Bretagne Occidentale, LEMAR (UMR 6539), Unité PFOM, Laboratoire ARN, Centre Ifremer de Brest, 29280 Plouzané, France
| | - Hans-Otto Pörtner
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany
- University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, 28359 Bremen, Germany
| | - Rainer Knust
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bentho-Pelagic Processes, Am Alten Hafen 26, 27568 Bremerhaven, Germany
| | - Felix Christopher Mark
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany
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18
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Lapointe D, Cooperman MS, Chapman LJ, Clark TD, Val AL, Ferreira MS, Balirwa JS, Mbabazi D, Mwanja M, Chhom L, Hannah L, Kaufman L, Farrell AP, Cooke SJ. Predicted impacts of climate warming on aerobic performance and upper thermal tolerance of six tropical freshwater fishes spanning three continents. CONSERVATION PHYSIOLOGY 2018; 6:coy056. [PMID: 30364036 PMCID: PMC6188536 DOI: 10.1093/conphys/coy056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 08/31/2018] [Accepted: 09/06/2018] [Indexed: 05/30/2023]
Abstract
Equatorial fishes, and the critically important fisheries based on them, are thought to be at-risk from climate warming because the fishes have evolved in a relatively aseasonal environment and possess narrow thermal tolerance windows that are close to upper thermal limits. We assessed survival, growth, aerobic performance and critical thermal maxima (CTmax) following acute and 21 d exposures to temperatures up to 4°C higher than current maxima for six species of freshwater fishes indigenous to tropical countries and of importance for human consumption. All six species showed 1.3-1.7°C increases in CTmax with a 4°C rise in acclimation temperature, values which match up well with fishes from other climatic regions, and five species had survival >87% at all temperatures over the treatment period. Specific growth rates varied among and within each species in response to temperature treatments. For all species, the response of resting metabolic rate (RMR) was consistently more dynamic than for maximum metabolic rate, but in general both acute temperature exposure and thermal acclimation had only modest effects on aerobic scope (AS). However, RMR increased after warm acclimation in 5 of 6 species, suggesting incomplete metabolic compensation. Taken in total, our results show that each species had some ability to perform at temperatures up to 4°C above current maxima, yet also displayed certain areas of concern for their long-term welfare. We therefore suggest caution against the overly broad generalization that all tropical freshwater fish species will face severe challenges from warming temperatures in the coming decades and that future vulnerability assessments should integrate multiple performance metrics as opposed to relying on a single response metric. Given the societal significance of inland fisheries in many parts of the tropics, our results clearly demonstrate the need for more species-specific studies of adaptive capacity to climate change-related challenges.
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Affiliation(s)
- Dominique Lapointe
- St. Lawrence River Institute of Environmental Sciences, Cornwall, ON, Canada
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON, Canada
| | - Michael S Cooperman
- Gordon and Betty Moore Center for Science, Conservation International, Arlington, VA, USA
| | | | - Timothy D Clark
- Deakin University, School of Life and Environmental Sciences, Geelong, Victoria, Australia
| | - Adalberto L Val
- Brazilian Institute for Research of the Amazon—INPA, Manaus, AM, Brazil
| | - Marcio S Ferreira
- Brazilian Institute for Research of the Amazon—INPA, Manaus, AM, Brazil
| | - John S Balirwa
- National Fisheries Resources Research Institute—NaFIRRI, Jinja, Uganda
| | - Dismas Mbabazi
- Aquaculture Research and Development Center—ARDC, NaFIRRI (Kajjansi), Kampala, Uganda
| | - Matthew Mwanja
- Aquaculture Research and Development Center—ARDC, NaFIRRI (Kajjansi), Kampala, Uganda
| | | | - Lee Hannah
- Bren School of Environmental Science & Management, University of California, Santa Barbara, CA, USA
| | - Les Kaufman
- Department of Biology, Boston University, Boston, MA, USA
| | - Anthony P Farrell
- Zoology Department and Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON, Canada
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19
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Wilson RE, Menning DM, Wedemeyer K, Talbot SL. A transcriptome resource for the Arctic Cod (Boreogadus saida). Mar Genomics 2018. [DOI: 10.1016/j.margen.2018.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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20
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Flynn EE, Todgham AE. Thermal windows and metabolic performance curves in a developing Antarctic fish. J Comp Physiol B 2017; 188:271-282. [PMID: 28988313 DOI: 10.1007/s00360-017-1124-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/04/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022]
Abstract
For ectotherms, temperature modifies the rate of physiological function across a temperature tolerance window depending on thermal history, ontogeny, and evolutionary history. Some adult Antarctic fishes, with comparatively narrow thermal windows, exhibit thermal plasticity in standard metabolic rate; however, little is known about the shape or breadth of thermal performance curves of earlier life stages of Antarctic fishes. We tested the effects of acute warming (- 1 to 8 °C) and temperature acclimation (2 weeks at - 1, 2, 4 °C) on survival and standard metabolic rate in early embryos of the dragonfish Gymnodraco acuticeps from McMurdo Sound, Ross Island, Antarctica. Contrary to predictions, embryos acclimated to warmer temperatures did not experience greater mortality and nearly all embryos survived acute warming to 8 °C. Metabolic performance curve height and shape were both significantly altered after 2 weeks of development at - 1 °C, with further increase in curve height, but not alteration of shape, with warm temperature acclimation. Overall metabolic rate temperature sensitivity (Q 10) from - 1 to 8 °C varied from 2.6 to 3.6, with the greatest thermal sensitivity exhibited by embryos at earlier developmental stages. Interclutch variation in metabolic rates, mass, and development of simultaneously collected embryos was also documented. Taken together, metabolic performance curves provide insight into the costs of early development under warming temperatures, with the potential for thermal sensitivity to be modified by dragonfish phenology and magnitude of seasonal changes in temperature.
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Affiliation(s)
- Erin E Flynn
- Department of Animal Sciences, University of California, Davis, CA, 95616, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California, Davis, CA, 95616, USA.
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21
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McArley TJ, Hickey AJR, Herbert NA. Chronic warm exposure impairs growth performance and reduces thermal safety margins in the common triplefin fish (Forsterygion lapillum). J Exp Biol 2017; 220:3527-3535. [DOI: 10.1242/jeb.162099] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/25/2017] [Indexed: 12/21/2022]
Abstract
Intertidal fish species face gradual chronic changes in temperature and greater extremes of acute thermal exposure through climate induced warming. As sea temperatures rise it has been proposed that whole animal performance will be impaired through oxygen and capacity limited thermal tolerance (OCLTT, reduced aerobic metabolic scope-MS) and, on acute exposure to high temperatures, thermal safety margins may be reduced due to constrained acclimation capacity of upper thermal limits. Using the New Zealand triplefin fish (Forsterygion lapillum), this study addressed how performance in terms of growth and metabolism (MS) and upper thermal tolerance limits would be affected by chronic exposure to elevated temperature. Growth was measured in fish acclimated (12 weeks) to present and predicted future temperatures and metabolic rates were then determined in fish at acclimation temperatures and with acute thermal ramping. In agreement with the OCLTT hypothesis chronic exposure to elevated temperature significantly reduced growth performance and MS. However, despite the prospect of impaired growth performance under warmer future summertime conditions an annual growth model revealed that elevated temperatures may only shift the timing of high growth potential and not the overall annual growth rate. While the upper thermal tolerance (i.e. critical thermal maxima) increased with exposure to warmer temperatures and was associated with depressed metabolic rates during acute thermal ramping, upper thermal tolerance did not differ between present and predicted future summertime temperatures. This suggests that warming may progressively decrease thermal safety margins for hardy generalist species and could limit the available habitat range of intertidal populations.
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Affiliation(s)
- Tristan. J. McArley
- Institute of Marine Science, University of Auckland, Leigh, Warkworth 0941, New Zealand
| | - Anthony J. R. Hickey
- School of Biological Sciences, University of Auckland, 3a Symonds Street, Thomas Building, Auckland, New Zealand
| | - Neill. A. Herbert
- Institute of Marine Science, University of Auckland, Leigh, Warkworth 0941, New Zealand
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