Yuzo R Yanagitsuru, Florian Mauduit, Alexis J Lundquist, Levi S Lewis, James A Hobbs, Tien-Chieh Hung, Richard E Connon, Nann A Fangue
{"title":"孵化温度对濒临灭绝的长鳍胡瓜鱼(Spirinchus thaleichthys)上限耐热性的影响。","authors":"Yuzo R Yanagitsuru, Florian Mauduit, Alexis J Lundquist, Levi S Lewis, James A Hobbs, Tien-Chieh Hung, Richard E Connon, Nann A Fangue","doi":"10.1093/conphys/coae004","DOIUrl":null,"url":null,"abstract":"<p><p>Upper thermal limits in many fish species are limited, in part, by the heart's ability to meet increased oxygen demand during high temperatures. Cardiac plasticity induced by developmental temperatures can therefore influence thermal tolerance. Here, we determined how incubation temperatures during the embryonic stage influence cardiac performance across temperatures during the sensitive larval stage of the imperiled longfin smelt. We transposed a cardiac assay for larger fish to newly hatched larvae that were incubated at 9°C, 12°C or 15°C. We measured heart rate over increases in temperature to identify the Arrhenius breakpoint temperature (T<sub>AB</sub>), a proxy for thermal optimum and two upper thermal limit metrics: temperature when heart rate is maximized (T<sub>peak</sub>) and when cardiac arrhythmia occurs (T<sub>Arr</sub>). Higher incubation temperatures increased T<sub>AB</sub>, T<sub>peak</sub> and T<sub>Arr</sub>, but high individual variation in all three metrics resulted in great overlap of individuals at T<sub>AB</sub>, T<sub>peak</sub> and T<sub>Arr</sub> across temperatures. We found that the temperatures at which 10% of individuals reached T<sub>peak</sub> or T<sub>Arr</sub> and temperatures at which number of individuals at T<sub>AB</sub> relative to T<sub>peak</sub> (ΔN(T<sub>AB,</sub>T<sub>peak</sub>)) was maximal, correlated more closely with upper thermal limits and thermal optima inferred from previous studies, compared to the mean values of the three cardiac metrics of the present study. Higher incubation temperatures increased the 10% T<sub>peak</sub> and T<sub>Arr</sub> thresholds but maximum ΔN(T<sub>AB,</sub>T<sub>peak</sub>) largely remained the same, suggesting that incubation temperatures modulate upper thermal limits but not T<sub>opt</sub> for a group of larvae. Overall, by measuring cardiac performance across temperatures, we defined upper thermal limits (10% thresholds; T<sub>peak</sub>, 14.4-17.5°C; T<sub>Arr</sub>, 16.9-20.2°C) and optima (ΔN(T<sub>AB,</sub>T<sub>peak</sub>), 12.4-14.4°C) that can guide conservation strategies for longfin smelt and demonstrated the potential of this cardiac assay for informing conservation plans for the early life stages of fish.</p>","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10858410/pdf/","citationCount":"0","resultStr":"{\"title\":\"Effects of incubation temperature on the upper thermal tolerance of the imperiled longfin smelt (<i>Spirinchus thaleichthys</i>).\",\"authors\":\"Yuzo R Yanagitsuru, Florian Mauduit, Alexis J Lundquist, Levi S Lewis, James A Hobbs, Tien-Chieh Hung, Richard E Connon, Nann A Fangue\",\"doi\":\"10.1093/conphys/coae004\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Upper thermal limits in many fish species are limited, in part, by the heart's ability to meet increased oxygen demand during high temperatures. Cardiac plasticity induced by developmental temperatures can therefore influence thermal tolerance. Here, we determined how incubation temperatures during the embryonic stage influence cardiac performance across temperatures during the sensitive larval stage of the imperiled longfin smelt. We transposed a cardiac assay for larger fish to newly hatched larvae that were incubated at 9°C, 12°C or 15°C. We measured heart rate over increases in temperature to identify the Arrhenius breakpoint temperature (T<sub>AB</sub>), a proxy for thermal optimum and two upper thermal limit metrics: temperature when heart rate is maximized (T<sub>peak</sub>) and when cardiac arrhythmia occurs (T<sub>Arr</sub>). Higher incubation temperatures increased T<sub>AB</sub>, T<sub>peak</sub> and T<sub>Arr</sub>, but high individual variation in all three metrics resulted in great overlap of individuals at T<sub>AB</sub>, T<sub>peak</sub> and T<sub>Arr</sub> across temperatures. We found that the temperatures at which 10% of individuals reached T<sub>peak</sub> or T<sub>Arr</sub> and temperatures at which number of individuals at T<sub>AB</sub> relative to T<sub>peak</sub> (ΔN(T<sub>AB,</sub>T<sub>peak</sub>)) was maximal, correlated more closely with upper thermal limits and thermal optima inferred from previous studies, compared to the mean values of the three cardiac metrics of the present study. Higher incubation temperatures increased the 10% T<sub>peak</sub> and T<sub>Arr</sub> thresholds but maximum ΔN(T<sub>AB,</sub>T<sub>peak</sub>) largely remained the same, suggesting that incubation temperatures modulate upper thermal limits but not T<sub>opt</sub> for a group of larvae. 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Effects of incubation temperature on the upper thermal tolerance of the imperiled longfin smelt (Spirinchus thaleichthys).
Upper thermal limits in many fish species are limited, in part, by the heart's ability to meet increased oxygen demand during high temperatures. Cardiac plasticity induced by developmental temperatures can therefore influence thermal tolerance. Here, we determined how incubation temperatures during the embryonic stage influence cardiac performance across temperatures during the sensitive larval stage of the imperiled longfin smelt. We transposed a cardiac assay for larger fish to newly hatched larvae that were incubated at 9°C, 12°C or 15°C. We measured heart rate over increases in temperature to identify the Arrhenius breakpoint temperature (TAB), a proxy for thermal optimum and two upper thermal limit metrics: temperature when heart rate is maximized (Tpeak) and when cardiac arrhythmia occurs (TArr). Higher incubation temperatures increased TAB, Tpeak and TArr, but high individual variation in all three metrics resulted in great overlap of individuals at TAB, Tpeak and TArr across temperatures. We found that the temperatures at which 10% of individuals reached Tpeak or TArr and temperatures at which number of individuals at TAB relative to Tpeak (ΔN(TAB,Tpeak)) was maximal, correlated more closely with upper thermal limits and thermal optima inferred from previous studies, compared to the mean values of the three cardiac metrics of the present study. Higher incubation temperatures increased the 10% Tpeak and TArr thresholds but maximum ΔN(TAB,Tpeak) largely remained the same, suggesting that incubation temperatures modulate upper thermal limits but not Topt for a group of larvae. Overall, by measuring cardiac performance across temperatures, we defined upper thermal limits (10% thresholds; Tpeak, 14.4-17.5°C; TArr, 16.9-20.2°C) and optima (ΔN(TAB,Tpeak), 12.4-14.4°C) that can guide conservation strategies for longfin smelt and demonstrated the potential of this cardiac assay for informing conservation plans for the early life stages of fish.
期刊介绍:
Conservation Physiology is an online only, fully open access journal published on behalf of the Society for Experimental Biology.
Biodiversity across the globe faces a growing number of threats associated with human activities. Conservation Physiology will publish research on all taxa (microbes, plants and animals) focused on understanding and predicting how organisms, populations, ecosystems and natural resources respond to environmental change and stressors. Physiology is considered in the broadest possible terms to include functional and mechanistic responses at all scales. We also welcome research towards developing and refining strategies to rebuild populations, restore ecosystems, inform conservation policy, and manage living resources. We define conservation physiology broadly and encourage potential authors to contact the editorial team if they have any questions regarding the remit of the journal.