{"title":"Monitoring the stress physiology of free-ranging mugger crocodiles (<i>Crocodylus palustris</i>) across diverse habitats within Central Gujarat, India.","authors":"Brinky Desai, Tathagata Bhowmik, Rohith Srinivasan, Nikhil Whitaker, Ratna Ghosal","doi":"10.1093/conphys/coae035","DOIUrl":"10.1093/conphys/coae035","url":null,"abstract":"<p><p>Animals face several challenges in their natural environment, and to cope with such conditions, they may exhibit contrasting physiological responses that directly affect their overall well-being and survival. In this study, we assessed physiological responses via faecal glucocorticoid metabolite (fGCM) measurements in free-ranging mugger crocodiles inhabiting diverse habitats in Gujarat, India. We sampled muggers within Charotar, a rural area (Zone A) with local people having high tolerance towards the presence of muggers, and Vadodara, a region having both urban (Zone B) and rural (Zone C) areas with high levels of human-mugger conflict (HMC). Further, muggers in Vadodara live in water bodies that are mostly polluted due to sewage disposal from adjoining chemical industries. To measure fGCM (mean ± SEM, ng/g dry faeces) levels in muggers, scats were collected during both breeding (<i>N</i> = 107 scats) and non-breeding (<i>N</i> = 22 scats) seasons from all three zones. We used captive muggers (a focal enclosure) to biologically validate (via capture and restraint) the selected fGCM assay (11-oxoetiocholanolone assay). We showed a significant (<i>P</i> < 0.05) 11-fold increase in fGCM levels between pre-capture (540.9 ± 149.2, <i>N</i> = 11) and post-capture (6259.7 ± 1150.5, <i>N</i> = 11) samples. The validated assay was applied to free-ranging muggers during the breeding season, and Zone A showed significantly (<i>P</i> < 0.05) lower fGCM levels (542.03 ± 71.3) compared to muggers of Zone B (1699.9 ± 180.8) and Zone C (1806.4 ± 243.2), both zones having high levels of HMC with polluted water bodies. A similar contrast in fGCM levels was also observed during the non-breeding season. Overall, the study demonstrated that fGCM levels in muggers varied across habitats, and such variation could be due to a multitude of ecological factors that the species experience in their immediate local environment. Moreover, high fGCM levels in muggers of Vadodara during both breeding and non-breeding seasons may indicate a condition of chronic stress, which could be maladaptive for the species.</p>","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11151695/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141263213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R J Lennox, M R Donaldson, G D Raby, K V Cook, L LaRochelle, J C Madden, S J Cooke, D A Patterson, S G Hinch
{"title":"Using vitality indicators to predict survival of aquatic animals released from fisheries","authors":"R J Lennox, M R Donaldson, G D Raby, K V Cook, L LaRochelle, J C Madden, S J Cooke, D A Patterson, S G Hinch","doi":"10.1093/conphys/coae034","DOIUrl":"https://doi.org/10.1093/conphys/coae034","url":null,"abstract":"Estimating the survival probability of animals released from fisheries can improve the overall understanding of animal biology with implications for fisheries management, conservation and animal welfare. Vitality indicators are simple visual measures of animal condition that change in response to stressors (like fisheries capture) and can be assessed to predict post-release survival. These indicators typically include immediate reflex responses which are typically combined into a score. Vitality indicators are straight-forward and non-invasive metrics that allow users to quantify how close (or far) an animal is from a normal, ‘healthy’ or baseline state, which in turn can be correlated with outcomes such as survival probability, given appropriate calibration. The literature on using vitality indicators to predict post-release survival of animals has grown rapidly over the past decade. We identified 136 papers that used vitality indicators in a fisheries context. These studies were primarily focused on marine and freshwater fishes, with a few examples using herptiles and crustaceans. The types of vitality indicators are diverse and sometimes taxa-specific (e.g. pinching leg of turtles, spraying water at nictitating membrane of sharks) with the most commonly used indicators being those that assess escape response or righting response given the vulnerability of animals when those reflexes are impaired. By presenting Pacific salmon fisheries as a case study, we propose a framework for using vitality indicators to predict survival across taxa and fisheries.","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conservation PhysiologyPub Date : 2024-05-28eCollection Date: 2024-01-01DOI: 10.1093/conphys/coae031
Giulia S Rossi, Alaa Elbassiouny, Jerrica Jamison, Kenneth C Welch
{"title":"Heat exposure limits pentose phosphate pathway activity in bumblebees.","authors":"Giulia S Rossi, Alaa Elbassiouny, Jerrica Jamison, Kenneth C Welch","doi":"10.1093/conphys/coae031","DOIUrl":"10.1093/conphys/coae031","url":null,"abstract":"<p><p>Bumblebee populations across the globe are experiencing substantial declines due to climate change, with major consequences for pollination services in both natural and agricultural settings. Using an economically important species, <i>Bombus impatiens</i>, we explored the physiological mechanisms that may cause susceptibility to extreme heat events. We tested the hypothesis that heat exposure limits the activity of the pentose phosphate pathway (PPP)-a parallel pathway to glycolysis that can use nectar sugar to generate antioxidant potential and combat oxidative stress. Using isotopically labelled glucose, we tracked PPP activity in <i>B. impatiens</i> at rest, during exercise and during a post-exercise recovery period under two different temperature regimes (22°C and 32°C). We found that the PPP is routinely used by <i>B. impatiens</i> at moderate temperatures, but that its activity is markedly reduced when ATP demands are high, such as during periods of exercise and heat exposure. We also exposed <i>B. impatiens</i> to either 22°C or 32°C for 5 hours and assessed levels of oxidative damage (lipid peroxidation, protein carbonyls) and antioxidant potential [reduced (GSH) and oxidized (GSSG) glutathione concentrations]. Interestingly, bees exhibited little oxidative damage after the thermal exposure, but we found a lower GSH:GSSG ratio in 32°C-exposed bees, reflecting lower antioxidant potential. Overall, our study demonstrates that acute heat stress severely limits PPP activity and may constrain antioxidant potential in <i>B. impatiens</i>. The repeated attenuation of this pathway in a warming climate may have more severe physiological consequences for this species, with potential implications for pollination services across North America.</p>","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11134105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141176484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conservation PhysiologyPub Date : 2024-05-27eCollection Date: 2024-01-01DOI: 10.1093/conphys/coae033
Kristen Petrov, James U Van Dyke, Arthur Georges, Claudia Keitel, Ricky-John Spencer
{"title":"Maternal diet influences fecundity in a freshwater turtle undergoing population decline.","authors":"Kristen Petrov, James U Van Dyke, Arthur Georges, Claudia Keitel, Ricky-John Spencer","doi":"10.1093/conphys/coae033","DOIUrl":"10.1093/conphys/coae033","url":null,"abstract":"<p><p>Food availability determines the amount of energy animals can acquire and allocate to reproduction and other necessary functions. Female animals that are food limited thus experience reduced energy available for reproduction. When this occurs, females may reduce frequency of reproductive events or the number or size of offspring per reproductive bout. We assessed how maternal diet affects reproductive output in adult female Murray River short-necked turtles, <i>Emydura macquarii,</i> from four wetlands in Victoria. We previously found that turtle diets differ in the composition of plants and animals between our study wetlands. In this study, we tested whether differences in turtle diet composition (i.e. plants and animals) at these wetlands were associated with differences in clutch mass, individual egg mass, bulk egg composition and hatching success. We found total clutch mass increased with maternal body size at each site. At sites where filamentous green algae were scarce and <i>E. macquarii</i> were carnivorous, females produced smaller clutches relative to body size compared to females from sites where algae were abundant, and turtles were more herbivorous. Individual egg mass, bulk egg composition and hatching success did not differ across wetlands. Isotopic analysis revealed significant positive relationships between the carbon and nitrogen isotopes (δ<sup>13</sup>C, δ<sup>15</sup>N) of the eggs and those of the mothers, indicating that mothers allocated ratios of carbon and nitrogen isotopes to their eggs similar to those present in their tissues. Our study suggests that at sites where females are more carnivorous due to a relative absence of algae, females produce smaller clutches, but other aspects of their reproduction are not significantly impacted. The reduction in clutch size associated with differences in the availability of dietary plants and animals may have long-term consequences for <i>E. macquarii</i> and other freshwater turtle species that are experiencing population declines.</p>","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11129712/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141159167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conservation PhysiologyPub Date : 2024-05-27eCollection Date: 2024-01-01DOI: 10.1093/conphys/coae032
Valentina S A Mella, Christine E Cooper, Madeline Karr, Andrew Krockenberger, George Madani, Elliot B Webb, Mark B Krockenberger
{"title":"Hot climate, hot koalas: the role of weather, behaviour and disease on thermoregulation.","authors":"Valentina S A Mella, Christine E Cooper, Madeline Karr, Andrew Krockenberger, George Madani, Elliot B Webb, Mark B Krockenberger","doi":"10.1093/conphys/coae032","DOIUrl":"10.1093/conphys/coae032","url":null,"abstract":"<p><p>Thermoregulation is critical for endotherms living in hot, dry conditions, and maintaining optimal core body temperature (<i>T</i><sub>b</sub>) in a changing climate is an increasingly challenging task for mammals. Koalas (<i>Phascolarctos cinereus</i>) have evolved physiological and behavioural strategies to maintain homeostasis and regulate their <i>T</i><sub>b</sub> but are thought to be vulnerable to prolonged heat. We investigated how weather, behaviour and disease influence <i>T</i><sub>b</sub> for wild, free-living koalas during summer in north-west New South Wales. We matched <i>T</i><sub>b</sub> with daily behavioural observations in an ageing population where chlamydial disease is prevalent. Each individual koala had similar <i>T</i><sub>b</sub> rhythms (average <i>T</i><sub>b</sub> = 36.4 ± 0.05°C), but male koalas had higher <i>T</i><sub>b</sub> amplitude and more pronounced daily rhythm than females. Disease disrupted the 24-hr circadian pattern of <i>T</i><sub>b</sub>. Koala <i>T</i><sub>b</sub> increased with ambient temperature (<i>T</i><sub>a</sub>). On the hottest day of the study (maximum <i>T</i><sub>a</sub> = 40.8°C), we recorded the highest (<i>T</i><sub>b</sub> = 40.8°C) but also the lowest (<i>T</i><sub>b</sub> = 32.4°C) <i>T</i><sub>b</sub> ever documented for wild koalas, suggesting that they are more heterothermic than previously recognized. This requires individuals to predict days of extreme <i>T</i><sub>a</sub> from overnight and early morning conditions, adjusting <i>T</i><sub>b</sub> regulation accordingly, and it has never been reported before for koalas. The large diel amplitude and low minimum <i>T</i><sub>b</sub> observed suggest that koalas at our study site are energetically and nutritionally compromised, likely due to their age. Behaviour (i.e. tree hugging and drinking water) was not effective in moderating <i>T</i><sub>b</sub>. These results indicate that <i>T</i><sub>a</sub> and koala <i>T</i><sub>b</sub> are strongly interconnected and reinforce the importance of climate projections for predicting the future persistence of koalas throughout their current distribution. Global climate models forecast that dry, hot weather will continue to escalate and drought events will increase in frequency, duration and severity. This is likely to push koalas and other arboreal folivores towards their thermal limit.</p>","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11129715/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141159147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wolfgang Lewandrowski, Emily P Tudor, Hayden Ajduk, Sean Tomlinson, Jason C Stevens
{"title":"Spatiotemporal variation in ecophysiological traits align with high resolution niche modelling in the short-range banded ironstone endemic Aluta quadrata","authors":"Wolfgang Lewandrowski, Emily P Tudor, Hayden Ajduk, Sean Tomlinson, Jason C Stevens","doi":"10.1093/conphys/coae030","DOIUrl":"https://doi.org/10.1093/conphys/coae030","url":null,"abstract":"Defining plant ecophysiological responses across natural distributions enables a greater understanding of the niche that plants occupy. Much of the foundational knowledge of species’ ecology and responses to environmental change across their distribution is often lacking, particularly for rare and threatened species, exacerbating management and conservation challenges. Combining high-resolution species distribution models (SDMs) with ecophysiological monitoring characterized the spatiotemporal variation in both plant traits and their interactions with their surrounding environment for the range-restricted Aluta quadrata Rye & Trudgen, and a common, co-occurring generalist, Eremophila latrobei subsp. glabra (L.S.Sm.) Chinnock., from the semi-arid Pilbara and Gascoyne region in northwest Western Australia. The plants reflected differences in gas exchange, plant health and plant water relations at sites with contrasting suitability from the SDM, with higher performance measured in the SDM-predicted high-suitability site. Seasonal differences demonstrated the highest variation across ecophysiological traits in both species, with higher performance in the austral wet season across all levels of habitat suitability. The results of this study allow us to effectively describe how plant performance in A. quadrata is distributed across the landscape in contrast to a common, widespread co-occurring species and demonstrate a level of confidence in the habitat suitability modelling derived from the SDM in predicting plant function determined through intensive ecophysiology monitoring programmes. In addition, the findings also provide a baseline approach for future conservation actions, as well as to explore the mechanisms underpinning the short-range endemism arid zone systems.","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141151848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rosalie J Harris, Philippa R Alvarez, Callum Bryant, Verónica F Briceño, Alicia M Cook, Andrea Leigh, Adrienne B Nicotra
{"title":"Acclimation of thermal tolerance in juvenile plants from three biomes is suppressed when extremes co-occur","authors":"Rosalie J Harris, Philippa R Alvarez, Callum Bryant, Verónica F Briceño, Alicia M Cook, Andrea Leigh, Adrienne B Nicotra","doi":"10.1093/conphys/coae027","DOIUrl":"https://doi.org/10.1093/conphys/coae027","url":null,"abstract":"Given the rising frequency of thermal extremes (heatwaves and cold snaps) due to climate change, comprehending how a plant’s origin affects its thermal tolerance breadth (TTB) becomes vital. We studied juvenile plants from three biomes: temperate coastal rainforest, desert and alpine. In controlled settings, plants underwent hot days and cold nights in a factorial design to examine thermal tolerance acclimation. We assessed thermal thresholds (Tcrit-hot and Tcrit-cold) and TTB. We hypothesized that (i) desert species would show the highest heat tolerance, alpine species the greatest cold tolerance and temperate species intermediate tolerance; (ii) all species would increase heat tolerance after hot days and cold tolerance after cold nights; (iii) combined exposure would broaden TTB more than individual conditions, especially in desert and alpine species. We found that biome responses were minor compared to the responses to the extreme temperature treatments. All plants increased thermal tolerance in response to hot 40°C days (Tcrit-hot increased by ~3.5°C), but there was minimal change in Tcrit-cold in response to the cold −2°C nights. In contrast, when exposed to both hot days and cold nights, on average, plants exhibited an antagonistic response in TTB, where cold tolerance decreased and heat tolerance was reduced, and so we did not see the bi-directional expansion we hypothesized. There was, however, considerable variation among species in these responses. As climate change intensifies, plant communities, especially in transitional seasons, will regularly face such temperature swings. Our results shed light on potential plant responses under these extremes, emphasizing the need for deeper species-specific thermal acclimation insights, ultimately guiding conservation efforts.","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141151771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Madison E. Kucinick, Kate E Charles, Kenrith Carter, Jonnel J. Edwards, Catherine Costlow, Melinda Wilkerson, Dawn Seddon, David Marancik
{"title":"Comparative plasma biochemistry analyte data in nesting leatherback (Dermochelys coriacea), foraging green (Chelonia mydas) and foraging and nesting hawksbill (Eretmochelys imbricata) sea turtles in Grenada, West Indies","authors":"Madison E. Kucinick, Kate E Charles, Kenrith Carter, Jonnel J. Edwards, Catherine Costlow, Melinda Wilkerson, Dawn Seddon, David Marancik","doi":"10.1093/conphys/coae028","DOIUrl":"https://doi.org/10.1093/conphys/coae028","url":null,"abstract":"Lay Summary Plasma biochemistry reference intervals were defined for nesting leatherback, foraging green and foraging hawksbill sea turtles, and descriptive statistics were calculated for nesting hawksbill turtles. Data support population health assessments and management of rehabilitating turtles in Grenada, and interspecies and conspecific comparisons contribute to our understanding of sea turtle physiology.","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140965656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conservation PhysiologyPub Date : 2024-05-17eCollection Date: 2024-01-01DOI: 10.1093/conphys/coae029
Kristin Denryter, Thomas R Stephenson, Kevin L Monteith
{"title":"Migratory behaviours are risk-sensitive to physiological state in an elevational migrant.","authors":"Kristin Denryter, Thomas R Stephenson, Kevin L Monteith","doi":"10.1093/conphys/coae029","DOIUrl":"10.1093/conphys/coae029","url":null,"abstract":"<p><p>Accretion of body fat by animals is an important physiological adaptation that may underpin seasonal behaviours, especially where it modulates risk associated with a particular behaviour. Using movement data from male Sierra Nevada bighorn sheep (<i>Ovis canadensis sierrae</i>), we tested the hypothesis that migratory behaviours were risk-sensitive to physiological state (indexed by body fat). Sierra bighorn face severe winter conditions at high elevations and higher predation risk at lower elevations. Given that large body fat stores ameliorate starvation risk, we predicted that having small body fat stores would force animals to migrate to lower elevations with more abundant food supplies. We also predicted that body fat stores would influence how far animals migrate, with the skinniest animals migrating the furthest down in elevation (to access the most abundant food supplies at that time of year). Lastly, we predicted that population-level rates of switching between migratory tactics would be inversely related to body fat levels because as body fat levels decrease, animals exhibiting migratory plasticity should modulate their risk of starvation by switching migratory tactics. Consistent with our predictions, probability of migration and elevational distance migrated increased with decreasing body fat, but effects differed amongst metapopulations. Population-level switching rates also were inversely related to population-level measures of body fat prior to migration. Collectively, our findings suggest migration was risk-sensitive to physiological state, and failure to accrete adequate fat may force animals to make trade-offs between starvation and predation risk. In complex seasonal environments, risk-sensitive migration yields a layer of flexibility that should aid long-term persistence of animals that can best modulate their risk by attuning behaviour to physiological state.</p>","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11109817/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141082957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tolerance threshold of a pelagic species in China to total dissolved gas supersaturation: from the perspective of survival characteristics and swimming ability","authors":"Hongtao Wang, Yuanming Wang, Kefeng Li, Ruifeng Liang, Weiyang Zhao","doi":"10.1093/conphys/coae023","DOIUrl":"https://doi.org/10.1093/conphys/coae023","url":null,"abstract":"Total dissolved gas (TDG) supersaturation downstream of dams can occur in the Yangtze River basin and is known to cause stress and even death in fish. Consequently, it is important to establish tolerance thresholds of endemic fish to protect local aquatic resources. We conducted experiments to assess survival characteristics and swimming ability of bighead carp, an important commercial fish dwelling in the Yangtze River, to evaluate its tolerance threshold to TDG supersaturation. The typical external symptoms of gas bubble trauma (GBT) were observed and the time when the fish lost equilibrium and died were recorded. The results showed that the mortality occurred when TDG level exceeded 125%, with obvious symptoms such as exophthalmos and bubbles on the head. The interval between loss of equilibrium and mortality decreased with an increase in TDG level. Neither exposure time nor TDG level significantly affected the critical swimming speed (Ucrit) of fish exposed to non-lethal exposure (110%, 120% and 125% TDG) over a 7 day period. Significant reductions in Ucrit were found under 130% and 135% TDG conditions when the exposure lasted 52.0 h and 42.9 h, respectively. The Ucrit also significantly decreased after exposure of 1.6 h under 140% TDG condition. Moreover, after exposure to 140% TDG for 39.2 h, 135% TDG for 56.5 h and 130% TDG for 95.9 h, bighead carp were transferred into air saturated water to recover for 24 h or 48 h; however, swimming performance remained impaired. The results of this study indicate that 125% TDG was the highest TDG level where limited mortality was observed and the swimming ability was not impaired, showing that 125% TDG can be set as the tolerance threshold of this species to guide the operation of dams in the Yangtze River Basin.","PeriodicalId":54331,"journal":{"name":"Conservation Physiology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141058576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}