Yangfan Zhang, F. Mauduit, Luca Pettinau, H. Ollivier, F. Lancien, Katja Anttila, A. Farrell, G. Claireaux
Phenotypic plasticity manifested after acclimatization is a very important source of biological variability among fish species. We hypothesized that hypoxic acclimation, besides potentially generating a temporary hypoxic respiratory phenotype, would also manifest as a continued benefit after re-acclimation to normoxia. Hence, we holistically characterized the respiratory phenotype of European sea bass (Dicentrarchus labrax) acclimated to normoxia with or without prior acclimation to hypoxia. Compared with the original normoxic phenotype, prior acclimation to hypoxia and return to normoxia produced a 27% higher absolute aerobic scope (AAS), a 24% higher citrate synthase activity in red muscle and a 28% lower excess post-exercise O2 consumption. Additional testing of hypoxia-acclimated fish under normoxia explored the specific effects of hypoxic acclimation. The hypoxic phenotype, when compared with the original normoxic phenotype, had a lower standard metabolic rate, a better hypoxia performance and a lower minimum PO2 for supporting 50% AAS. Given this respiratory malleability, general predictions for marine fish exploiting a more hypoxic future should better consider respiratory plasticity and prolonged effects of hypoxic exposures.
{"title":"Respiratory plasticity during acclimation to hypoxia and following a recovery in normoxia","authors":"Yangfan Zhang, F. Mauduit, Luca Pettinau, H. Ollivier, F. Lancien, Katja Anttila, A. Farrell, G. Claireaux","doi":"10.1139/cjz-2022-0158","DOIUrl":"https://doi.org/10.1139/cjz-2022-0158","url":null,"abstract":"Phenotypic plasticity manifested after acclimatization is a very important source of biological variability among fish species. We hypothesized that hypoxic acclimation, besides potentially generating a temporary hypoxic respiratory phenotype, would also manifest as a continued benefit after re-acclimation to normoxia. Hence, we holistically characterized the respiratory phenotype of European sea bass (Dicentrarchus labrax) acclimated to normoxia with or without prior acclimation to hypoxia. Compared with the original normoxic phenotype, prior acclimation to hypoxia and return to normoxia produced a 27% higher absolute aerobic scope (AAS), a 24% higher citrate synthase activity in red muscle and a 28% lower excess post-exercise O2 consumption. Additional testing of hypoxia-acclimated fish under normoxia explored the specific effects of hypoxic acclimation. The hypoxic phenotype, when compared with the original normoxic phenotype, had a lower standard metabolic rate, a better hypoxia performance and a lower minimum PO2 for supporting 50% AAS. Given this respiratory malleability, general predictions for marine fish exploiting a more hypoxic future should better consider respiratory plasticity and prolonged effects of hypoxic exposures.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43244779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Miller, T. Jung, Piia M. Kukka, J. Reynolds, R. Grove, G. Stenson, R. Rogers
Allometric analyses of sexually selected structures have revealed many patterns of evolutionary and behavioural significance (e.g. in weapons, ornaments, genitalia). We investigated allometry of the baculum (penis bone) relative to body size in adults of three large mustelids: wolverine (Gulo gulo (Linnaeus, 1758)), northern river otter (Lontra canadensis (Schreber, 1776)), and sea otter (Enhydra lutris (Linnaeus, 1758)). Bacular growth took place over a longer period than body growth. Correlations among bacular variables were positive. No regression slopes expressed positive allometry (i.e. slope > 1 for linear variables). These trends point to the possibility that bacular size is adapted to average size of the reproductive tract of sexually mature female northern river otters and possibly sea otters, and that pre-ejaculatory (“pre-copulatory”) selection is highest in those species. Bacular size varied more than skull or limb-bone size; bacular shape also varied greatly. Species differed in size and complexity of the urethral groove and bacular apex, suggesting functional differences in intromission. Substantial variation in bacular shape resulted from healed fractures, especially in sea otter. Knowledge of copulatory behaviour, age of breeding, female reproductive anatomy, and genitalic interactions during intromission is needed for fuller understanding of bacular anatomy, allometry, and variation for these species.
{"title":"Growth, allometry, and characteristics of a sexually selected structure in wolverine (Gulo gulo(Linnaeus, 1758)), northern river otter (Lontra canadensis(Linnaeus, 1758)), and sea otter (Enhydra lutris(Linnaeus, 1758))","authors":"E. Miller, T. Jung, Piia M. Kukka, J. Reynolds, R. Grove, G. Stenson, R. Rogers","doi":"10.1139/cjz-2022-0202","DOIUrl":"https://doi.org/10.1139/cjz-2022-0202","url":null,"abstract":"Allometric analyses of sexually selected structures have revealed many patterns of evolutionary and behavioural significance (e.g. in weapons, ornaments, genitalia). We investigated allometry of the baculum (penis bone) relative to body size in adults of three large mustelids: wolverine (Gulo gulo (Linnaeus, 1758)), northern river otter (Lontra canadensis (Schreber, 1776)), and sea otter (Enhydra lutris (Linnaeus, 1758)). Bacular growth took place over a longer period than body growth. Correlations among bacular variables were positive. No regression slopes expressed positive allometry (i.e. slope > 1 for linear variables). These trends point to the possibility that bacular size is adapted to average size of the reproductive tract of sexually mature female northern river otters and possibly sea otters, and that pre-ejaculatory (“pre-copulatory”) selection is highest in those species. Bacular size varied more than skull or limb-bone size; bacular shape also varied greatly. Species differed in size and complexity of the urethral groove and bacular apex, suggesting functional differences in intromission. Substantial variation in bacular shape resulted from healed fractures, especially in sea otter. Knowledge of copulatory behaviour, age of breeding, female reproductive anatomy, and genitalic interactions during intromission is needed for fuller understanding of bacular anatomy, allometry, and variation for these species.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46919748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We describe a slender immature female blindsnake from the main airport in Dili, Timor-Leste, as a new species of Indotyphlops, adding a third species to the country's known blindsnake fauna of Sundatyphlops polygrammicus (Schlegel, 1839) and Virgotyphlops braminus (Daudin, 1803). The new species has the following combination of characteristics: small size (snout–vent length = 119 mm), slender body (relative body thickness 71), T-V supralabial imbrication pattern, relative rostral width 0.36, 434 middorsal scales, relative tail length 1.7%, absence of enlarged occipital scales, and apical spine absent. The snake was found in an ant nest under several flat rocks near the fuel depot of Nicolau Lobato International Airport, and this habitat and the discovery in a busy location with heavy human impacts indicate that the species is likely a primarily subterranean myrmeco- or termitophage.
{"title":"“Anteaters” under the airport: a slender new species of blindsnake, genus Indotyphlops, from Timor-Leste (Scolecophidia: Typhlopidae: Asiatyphlopinae)","authors":"M. O’Shea, V. Wallach, Emma Hsiao, H. Kaiser","doi":"10.1139/cjz-2022-0097","DOIUrl":"https://doi.org/10.1139/cjz-2022-0097","url":null,"abstract":"We describe a slender immature female blindsnake from the main airport in Dili, Timor-Leste, as a new species of Indotyphlops, adding a third species to the country's known blindsnake fauna of Sundatyphlops polygrammicus (Schlegel, 1839) and Virgotyphlops braminus (Daudin, 1803). The new species has the following combination of characteristics: small size (snout–vent length = 119 mm), slender body (relative body thickness 71), T-V supralabial imbrication pattern, relative rostral width 0.36, 434 middorsal scales, relative tail length 1.7%, absence of enlarged occipital scales, and apical spine absent. The snake was found in an ant nest under several flat rocks near the fuel depot of Nicolau Lobato International Airport, and this habitat and the discovery in a busy location with heavy human impacts indicate that the species is likely a primarily subterranean myrmeco- or termitophage.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42597048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Rugg, C. Ribic, D. Donner, A. J. Beck, D. Wolcott, Susan. Reinecke, Dan Eklund
Beaver management requires understanding beaver habitat preferences. Despite the American beaver (Castor canadensis Kuhl, 1820) being relatively common in the upper Midwest region of the United States, there are no beaver habitat relationship models based on this area. We used 1,735 colonization events from long-term monitoring data generated by the Chequamegon-Nicolet National Forest in northern Wisconsin, USA, to determine what geomorphological and biological factors were selected by beavers colonizing new sites. We developed and evaluated prediction performance for three colonization models: geomorphology factors only, geomorphology and vegetation factors, and a full colonization model based on geomorphology, vegetation, and availability of dispersing beavers. Overall, the geomorphology-vegetation-colonizer model was the best model, predicting actual colony locations better than the other two models. Spatially, the landscape open to beaver colonization was a mosaic of streams with suitable and unsuitable habitat. These models improve our understanding of how beaver site selection factors in the upper Midwest region differ from factors identified in the literature for the western and eastern United States. This information may be useful for land managers in this region seeking to spatially target resources for restoring northern forest landscapes such as the Chequamegon-Nicolet National Forest.
{"title":"Factors affecting site selection by beavers colonizing streams in the upper Midwest region of the United States","authors":"D. Rugg, C. Ribic, D. Donner, A. J. Beck, D. Wolcott, Susan. Reinecke, Dan Eklund","doi":"10.1139/cjz-2022-0186","DOIUrl":"https://doi.org/10.1139/cjz-2022-0186","url":null,"abstract":"Beaver management requires understanding beaver habitat preferences. Despite the American beaver (Castor canadensis Kuhl, 1820) being relatively common in the upper Midwest region of the United States, there are no beaver habitat relationship models based on this area. We used 1,735 colonization events from long-term monitoring data generated by the Chequamegon-Nicolet National Forest in northern Wisconsin, USA, to determine what geomorphological and biological factors were selected by beavers colonizing new sites. We developed and evaluated prediction performance for three colonization models: geomorphology factors only, geomorphology and vegetation factors, and a full colonization model based on geomorphology, vegetation, and availability of dispersing beavers. Overall, the geomorphology-vegetation-colonizer model was the best model, predicting actual colony locations better than the other two models. Spatially, the landscape open to beaver colonization was a mosaic of streams with suitable and unsuitable habitat. These models improve our understanding of how beaver site selection factors in the upper Midwest region differ from factors identified in the literature for the western and eastern United States. This information may be useful for land managers in this region seeking to spatially target resources for restoring northern forest landscapes such as the Chequamegon-Nicolet National Forest.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"25 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41302270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Valerie M. Kearny, R. W. Perry, T. Risch, Virginie Rolland
Understanding microhabitat use is needed to make sound conservation decisions for at-risk, patchy-habitat specialists. Rock habitats offer unique microclimatic refugia for wildlife. Eastern Small-footed Bats (Myotis leibii (Audubon and Bachman, 1842)) use rock roosts during the summer, but data on these summer roosts are lacking for this species classified as (critically) imperiled in several US states and Canadian provinces and as globally endangered. Our goal was to characterize the structure and microclimate of M. leibii roosts at the southwestern periphery of their range. We predicted that M. leibii roost temperatures would be warmer and less variable than ambient temperatures and that solitary bats would use horizontal roosts cooler at night, whereas maternity group roosts would be vertical and warmer at night. During summers 2019 and 2020, we recorded physical (e.g., width) and temperature attributes of 58 M. leibii roosts at 16 sites in the Ouachita Mountains. Crevice roosts of M. leibii had narrow dimensions like elsewhere in their range and roost temperatures (measured with iButtons) were warmer and more variable than ambient temperatures. Group roosts were larger and had more stable temperatures than solitary roosts. These findings may be useful for assessing population threats, monitoring roost suitability, identifying roost-rich areas that need protection, and even planning artificial roost structures where natural roosts are limited.
了解微栖息地的使用情况是为处于危险中的斑块栖息地专家做出合理的保护决策所必需的。岩石栖息地为野生动物提供了独特的小气候避难所。东部小脚蝙蝠(Myotis leibii, Audubon and Bachman, 1842)在夏季栖息在岩石上，但缺乏关于这些夏季栖息的数据，该物种在美国几个州和加拿大省份被列为(极度)濒危物种，在全球范围内处于濒危状态。我们的目的是表征莱比密蛾栖息地西南边缘的结构和小气候。我们预测lebii蝙蝠的栖息地温度会比环境温度更温暖，变化更小，并且独居蝙蝠会在夜间使用较冷的水平栖息地，而母蝙蝠群的栖息地则会在夜间使用垂直的温暖栖息地。在2019年和2020年夏季，我们记录了瓦希托山脉16个地点58个M. leibii栖息地的物理(例如宽度)和温度属性。与其他地方一样，莱比夜蛾的缝隙栖息地尺寸狭窄，栖息地温度(用iButtons测量)比环境温度更温暖，变化更大。群栖比单栖更大，温度更稳定。这些发现可能有助于评估种群威胁、监测栖息地适宜性、确定需要保护的栖息地丰富地区，甚至在自然栖息地有限的地方规划人工栖息地结构。
{"title":"Microhabitat of Myotis leibii summer roosts at the southwestern periphery of their range","authors":"Valerie M. Kearny, R. W. Perry, T. Risch, Virginie Rolland","doi":"10.1139/cjz-2022-0137","DOIUrl":"https://doi.org/10.1139/cjz-2022-0137","url":null,"abstract":"Understanding microhabitat use is needed to make sound conservation decisions for at-risk, patchy-habitat specialists. Rock habitats offer unique microclimatic refugia for wildlife. Eastern Small-footed Bats (Myotis leibii (Audubon and Bachman, 1842)) use rock roosts during the summer, but data on these summer roosts are lacking for this species classified as (critically) imperiled in several US states and Canadian provinces and as globally endangered. Our goal was to characterize the structure and microclimate of M. leibii roosts at the southwestern periphery of their range. We predicted that M. leibii roost temperatures would be warmer and less variable than ambient temperatures and that solitary bats would use horizontal roosts cooler at night, whereas maternity group roosts would be vertical and warmer at night. During summers 2019 and 2020, we recorded physical (e.g., width) and temperature attributes of 58 M. leibii roosts at 16 sites in the Ouachita Mountains. Crevice roosts of M. leibii had narrow dimensions like elsewhere in their range and roost temperatures (measured with iButtons) were warmer and more variable than ambient temperatures. Group roosts were larger and had more stable temperatures than solitary roosts. These findings may be useful for assessing population threats, monitoring roost suitability, identifying roost-rich areas that need protection, and even planning artificial roost structures where natural roosts are limited.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42503364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peter Michael Baker, Christian A. Therrien, C. A. Muir, S. Garner, B. Neff
The consumption of invasive, high-thiaminase prey fishes can cause thiamine deficiency, which has been hypothesized to be a major barrier for lake trout (Salvelinus namaycush Walbaum in Artedi, 1792) restoration in the Great Lakes. In fishes, an understudied aspect of thiamine deficiency is its effect on cardiac function, despite evidence of this effect in mammals. Here, parr of two strains of lake trout (Seneca and Slate) were raised on either a control or high-thiaminase diet for nine months. We then measured cardiac function and morphology, particularly as it relates to the ability of the heart to meet oxygen demands at warmer water temperatures. The thiaminase diet was associated with significant heart enlargement and reduced cardiac performance at high temperatures. These effects were observed in both strains, but were more pronounced in Slate strain fish. Our data suggest that dietary thiaminase impairs cardiac function in fishes, and that these impairments may become increasingly important as water temperatures increase through climate change.
食用入侵性的高硫胺酶猎物鱼类会导致硫胺素缺乏，这被认为是五大湖湖鳟鱼（Salvelinus namaycush-Walbaum in Artedi，1792）恢复的主要障碍。在鱼类中，硫胺素缺乏症的一个研究不足的方面是它对心脏功能的影响，尽管有证据表明哺乳动物有这种影响。在这里，两种湖鳟（Seneca和Slate）的parr在对照或高硫胺酶饮食中饲养了九个月。然后，我们测量了心脏功能和形态，特别是当它与心脏在温暖的水温下满足氧气需求的能力有关时。硫胺酶饮食与心脏明显增大和高温下心脏功能下降有关。在这两种鱼类中都观察到了这些影响，但在Slate鱼类中更为明显。我们的数据表明，饮食中的硫胺酶会损害鱼类的心脏功能，随着气候变化导致水温升高，这些损害可能变得越来越重要。
{"title":"Dietary thiaminase impairs cardiac function and increases heart size in lake trout (Salvelinus namaycush)","authors":"Peter Michael Baker, Christian A. Therrien, C. A. Muir, S. Garner, B. Neff","doi":"10.1139/cjz-2023-0012","DOIUrl":"https://doi.org/10.1139/cjz-2023-0012","url":null,"abstract":"The consumption of invasive, high-thiaminase prey fishes can cause thiamine deficiency, which has been hypothesized to be a major barrier for lake trout (Salvelinus namaycush Walbaum in Artedi, 1792) restoration in the Great Lakes. In fishes, an understudied aspect of thiamine deficiency is its effect on cardiac function, despite evidence of this effect in mammals. Here, parr of two strains of lake trout (Seneca and Slate) were raised on either a control or high-thiaminase diet for nine months. We then measured cardiac function and morphology, particularly as it relates to the ability of the heart to meet oxygen demands at warmer water temperatures. The thiaminase diet was associated with significant heart enlargement and reduced cardiac performance at high temperatures. These effects were observed in both strains, but were more pronounced in Slate strain fish. Our data suggest that dietary thiaminase impairs cardiac function in fishes, and that these impairments may become increasingly important as water temperatures increase through climate change.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44245538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah B. Wilson, Robert A. Gitzen, S. Ditchkoff, Todd D. Steury
Scatterhoarder responses to factors that influence stored food (i.e. flooding) is important given the strong reliance on hoarded food for survival. We examined how eastern gray squirrels (Sciurus carolinensis, Gmelin 1778) have adapted to a seasonally flooded ecosystem in Alabama. Our study area was dry September – November and flooded the rest of the year. We predicted squirrels would respond to flooding by storing food in areas that stay dry during winter, seasonally shifting to dry habitat, or decreasing the amount of hard mast in their winter diet. We also examined previously reported survival differences between the dry and flooded seasons. During the dry season, 72% of acorns were buried in areas that later flooded. Habitat use did not change significantly during the flooded and dry seasons; however, squirrels used habitat that stayed dry during flooding to a greater degree during non-flood seasons. The amount of hard mast in the diet did not change significantly between the dry and flooded seasons. However, squirrels were more likely to die during the flooded season (P = 0.02). We did not find any behavioral adaptations to seasonal flooding. Further research is needed to fully understand the effects of fluctuating environmental conditions on scatterhoarders.
{"title":"Behavioral Adaptations of Scatterhoarders to Seasonal Flooding","authors":"Sarah B. Wilson, Robert A. Gitzen, S. Ditchkoff, Todd D. Steury","doi":"10.1139/cjz-2023-0024","DOIUrl":"https://doi.org/10.1139/cjz-2023-0024","url":null,"abstract":"Scatterhoarder responses to factors that influence stored food (i.e. flooding) is important given the strong reliance on hoarded food for survival. We examined how eastern gray squirrels (Sciurus carolinensis, Gmelin 1778) have adapted to a seasonally flooded ecosystem in Alabama. Our study area was dry September – November and flooded the rest of the year. We predicted squirrels would respond to flooding by storing food in areas that stay dry during winter, seasonally shifting to dry habitat, or decreasing the amount of hard mast in their winter diet. We also examined previously reported survival differences between the dry and flooded seasons. During the dry season, 72% of acorns were buried in areas that later flooded. Habitat use did not change significantly during the flooded and dry seasons; however, squirrels used habitat that stayed dry during flooding to a greater degree during non-flood seasons. The amount of hard mast in the diet did not change significantly between the dry and flooded seasons. However, squirrels were more likely to die during the flooded season (P = 0.02). We did not find any behavioral adaptations to seasonal flooding. Further research is needed to fully understand the effects of fluctuating environmental conditions on scatterhoarders.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41553261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Predation of fish released as part of conservation aquaculture programs may undermine conservation goals. Identification of factors influencing predation, therefore, can inform management decisions that minimize predation losses. For the endangered Nechako white sturgeon (Acipenser transmontanus Richardson, 1836), the survival of individuals released as part of a conservation aquaculture program is threatened by river otter (Lontra canadensis (Schreber, 1777)) predation. Through the recovery of sturgeon PIT tags from otter latrines, we set out to quantify the extent of predation, identify spatial patterns in predation including identifying predation hotspots, and understand the timing of predation. The recovery of 3.9% of PIT tags from the hatchery-released sturgeon represents a minimum predation estimate based on several identified factors. The distribution of predation hotspots varied by release cohort, with some consistent hotspots among cohorts. An apparent decrease in predation in recent years was seen in conjunction with fewer live captures and lower release numbers, suggesting some level of density dependent predation. Results from this study can be used to contribute to management decisions related to Nechako white sturgeon recovery efforts, inform further research needs, and contribute to a growing knowledge of sturgeon predation.
{"title":"Investigating Patterns and Extent of Predation of Hatchery-Reared Juvenile Nechako White Sturgeon (Acipenser transmontanus) by North American River Otter (Lontra canadensis) in the Nechako River, British Columbia, Canada","authors":"C. Babey, N. Gantner, J. Shrimpton","doi":"10.1139/cjz-2022-0148","DOIUrl":"https://doi.org/10.1139/cjz-2022-0148","url":null,"abstract":"Predation of fish released as part of conservation aquaculture programs may undermine conservation goals. Identification of factors influencing predation, therefore, can inform management decisions that minimize predation losses. For the endangered Nechako white sturgeon (Acipenser transmontanus Richardson, 1836), the survival of individuals released as part of a conservation aquaculture program is threatened by river otter (Lontra canadensis (Schreber, 1777)) predation. Through the recovery of sturgeon PIT tags from otter latrines, we set out to quantify the extent of predation, identify spatial patterns in predation including identifying predation hotspots, and understand the timing of predation. The recovery of 3.9% of PIT tags from the hatchery-released sturgeon represents a minimum predation estimate based on several identified factors. The distribution of predation hotspots varied by release cohort, with some consistent hotspots among cohorts. An apparent decrease in predation in recent years was seen in conjunction with fewer live captures and lower release numbers, suggesting some level of density dependent predation. Results from this study can be used to contribute to management decisions related to Nechako white sturgeon recovery efforts, inform further research needs, and contribute to a growing knowledge of sturgeon predation.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64234096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. G. Lopes, D. A. Monteiro, E. S. Vasconcelos, A. Kalinin
Feeding regimes are a critical process to ensure survival and reproduction, which modulate several behavioral and physiological patterns of ectotherms, especially cardiovascular adjustments. However, crocodilian myocardial contractile function after food intake remains understudied. We investigated the importance of ventricular myocardial contractility during digestion in the broad-snouted caiman, Caiman latirostris Daudin, 1801. Isometric ventricle preparations and Ca2+-handling protein expression were used to investigate the effects of prolonged fasting (30 days) and feeding (48 h after feeding on meals at 15% of body mass) on cardiac function. Upon feeding, there was no significant difference in relative ventricular mass. The cardiac response of the caiman to digestion was characterized by upregulation of the Na+/Ca2+ exchanger expression and an increase in myocardial contractility (positive inotropism and lusitropism) within the physiological range of heart rate. The digesting caiman's ventricular myocardium was able to maintain faster kinetics of contraction and relaxation, allowing for significantly increased cardiac pumping capacity at higher pacing frequencies. Our results demonstrated that the myocardium of broad-snouted caimans exhibits specializations in excitation–contraction coupling, which can provide a means to support high cardiovascular performance during digestion.
{"title":"Contractile function of fasting and digesting broad-snouted caiman (Caiman latirostris)","authors":"A. G. Lopes, D. A. Monteiro, E. S. Vasconcelos, A. Kalinin","doi":"10.1139/cjz-2022-0180","DOIUrl":"https://doi.org/10.1139/cjz-2022-0180","url":null,"abstract":"Feeding regimes are a critical process to ensure survival and reproduction, which modulate several behavioral and physiological patterns of ectotherms, especially cardiovascular adjustments. However, crocodilian myocardial contractile function after food intake remains understudied. We investigated the importance of ventricular myocardial contractility during digestion in the broad-snouted caiman, Caiman latirostris Daudin, 1801. Isometric ventricle preparations and Ca2+-handling protein expression were used to investigate the effects of prolonged fasting (30 days) and feeding (48 h after feeding on meals at 15% of body mass) on cardiac function. Upon feeding, there was no significant difference in relative ventricular mass. The cardiac response of the caiman to digestion was characterized by upregulation of the Na+/Ca2+ exchanger expression and an increase in myocardial contractility (positive inotropism and lusitropism) within the physiological range of heart rate. The digesting caiman's ventricular myocardium was able to maintain faster kinetics of contraction and relaxation, allowing for significantly increased cardiac pumping capacity at higher pacing frequencies. Our results demonstrated that the myocardium of broad-snouted caimans exhibits specializations in excitation–contraction coupling, which can provide a means to support high cardiovascular performance during digestion.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43433445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Tremblay, Gabriel L. Fontaine, J. Savard, Jean‐Michel Béland, C. Hébert, J. Ibarzabal
Knowledge on the diet of the Black-backed Woodpecker (Picoides arcticus Swainson, 1832) is fragmentary and relies on a limited number of studies. Gaps remain in our understanding of the plasticity of its diet, particularly in the eastern part of its range. The main objective of this study was to assess the diet of Black-backed Woodpeckers in burned and unburned habitats and among sexes and ages in Québec. We collected feces and fecal bags from unburned and burned habitats in the Central Laurentians ecoregion of the eastern boreal shield ecozone, and assessed diets based on identified prey items. Buprestidae and Cerambycidae of the subfamily Lamiinae were predominant prey for adult Black-backed Woodpeckers in burned habitats, and the Pythidae Pytho niger (Kirby, 1837) and Lamiinae were the most prevalent prey in unburned habitats. Lamiinae were the most predominant prey items provisioned to nestling in burned habitat while P. niger was their predominant food in unburned habitat, followed by Cerambycidae (without Lamiinae) and Lamiinae. Our results present new insights into Black-backed Woodpecker diet where parents feed their offspring with the largest prey available, potentially providing higher fitness for their offspring. Furthermore, our study confirms that Black-backed Woodpeckers, at least in the eastern part of its range, are not restricted to feed on Lamiinae, but are rather opportunistic in taking advantage from resource-pulse interactions provided by recently disturbed habitats, especially from recently burned habitats
{"title":"Premium food for offspring? Black-backed Woodpecker (Picoides arcticus) diet during breeding season in eastern Canada","authors":"J. Tremblay, Gabriel L. Fontaine, J. Savard, Jean‐Michel Béland, C. Hébert, J. Ibarzabal","doi":"10.1139/cjz-2022-0176","DOIUrl":"https://doi.org/10.1139/cjz-2022-0176","url":null,"abstract":"Knowledge on the diet of the Black-backed Woodpecker (Picoides arcticus Swainson, 1832) is fragmentary and relies on a limited number of studies. Gaps remain in our understanding of the plasticity of its diet, particularly in the eastern part of its range. The main objective of this study was to assess the diet of Black-backed Woodpeckers in burned and unburned habitats and among sexes and ages in Québec. We collected feces and fecal bags from unburned and burned habitats in the Central Laurentians ecoregion of the eastern boreal shield ecozone, and assessed diets based on identified prey items. Buprestidae and Cerambycidae of the subfamily Lamiinae were predominant prey for adult Black-backed Woodpeckers in burned habitats, and the Pythidae Pytho niger (Kirby, 1837) and Lamiinae were the most prevalent prey in unburned habitats. Lamiinae were the most predominant prey items provisioned to nestling in burned habitat while P. niger was their predominant food in unburned habitat, followed by Cerambycidae (without Lamiinae) and Lamiinae. Our results present new insights into Black-backed Woodpecker diet where parents feed their offspring with the largest prey available, potentially providing higher fitness for their offspring. Furthermore, our study confirms that Black-backed Woodpeckers, at least in the eastern part of its range, are not restricted to feed on Lamiinae, but are rather opportunistic in taking advantage from resource-pulse interactions provided by recently disturbed habitats, especially from recently burned habitats","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48376125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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