The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis,Pilleri&Gihr,1972;YFP)is an exclusively freshwater cetacean species inhabiting the Yangtze River and its connecting large lakes.As the prima...The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis,Pilleri&Gihr,1972;YFP)is an exclusively freshwater cetacean species inhabiting the Yangtze River and its connecting large lakes.As the primary line of defense in maintaining physiological equilibrium,the epidermis of the porpoise is expected to have undergone structural adaptations due to the shift from the marine to the freshwater environment.This study compared the microstructural and ultrastructural features of the epidermis of YFP and its marine counterpart,the East Asian finless porpoise(Neophocaena asiaeorientalis sunameri,Pilleri&Gihr,1975;EAFP).Microscopic structural observations and statistical analyses of the epidermal thickness demonstrated no significant differences in the cell structure or distribution between the two porpoise species.However,the epidermis of the YFP contained more abundant stratum basale cells.The outermost lipid stratum corneum exhibited a thinner cell layer with wider neutral lipid droplets to resist the passive entry of water molecules in the hypotonic environment.In contrast,for the EAFp,a more uniformly arranged stratum basale in the epidermis led to denser keratin fibers and robust desmosomes within each epidermal layer at the ultrastructural level.This tight arrangement of cells can reduce transepidermal water loss(TEWL)in an environment with higher osmotic pressure.In conclusion,the 2 finless porpoise species appear to employ different epidermal mechanisms to adapt to their distinct osmotic environments.The YFP appears to possess a"lipid waterproofing"epidermal structure,while the EAFP possesses a"thick and compact water-retaining"epidermal structure to copewithpotentialwaterloss.展开更多
Citizen science is a popular method for the long-term monitoring of the distribution of wild animals.The application of these methods in different species and environments still poses challenges,especially for aquatic...Citizen science is a popular method for the long-term monitoring of the distribution of wild animals.The application of these methods in different species and environments still poses challenges,especially for aquatic animals.In this study,we investigated the distribution of the Bryde’s whale(Balaenoptera edeni)in the Beibu Gulf of China by using scientific boat-based surveys and citizen science approaches using 2 different methods of data collection.First,we built our mobile app(Whale Guard)and installed it on fishermen’s phones.Second,we used a popular instant messaging app(WeChat)to create an online fisherman community.We found that the mobile phone app collected far fewer reports(5 reports)than the online community group(42 reports,P<0.01).By using a variety of incentives,we maintained the fisherman’s community’s activity without significant user loss(P<0.01).We also found that the locations collected by social media applications in this study were consistent with observations from scientific boat-based transect surveys.The sightings distribution of Bryde’s whales differed from those in previous surveys in that they were present across larger areas.Social media apps reported that 69%of reports was confirmed by more than one person,whereas Whale Guard reports were much lower(0,P<0.001).Community-based citizen science can greatly contribute to the long-term monitoring of Bryde’s whales,and it has successfully overcome the challenges of data accessibility,accuracy,and fragmentation.Our study shows how to appropriately use citizen science in different community groups and community-based approaches make them useful for large baleen whale surveys.展开更多
The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),a critically endangered species,is the only cetacean species in the Yangtze River following the functional extinction of baiji(Lipotes vexillif...The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),a critically endangered species,is the only cetacean species in the Yangtze River following the functional extinction of baiji(Lipotes vexillifer).To inform conservation actions,two important questions need to be addressed:what is the threshold value of survival rate,and what is the threshold value of population size?We calculate the instantaneous rate of population increase(¯r)for the Yangtze finless porpoise for various combinations of the calf and the non-calf survival rates.We also test the probability of extinction for different minimum carrying capacities for 100 and 500 years using a stable population model.The threshold value of the non-calf survival rate is never lower than 0.869,but current estimates from field data have been far below this threshold.Our model based on extinction probability and carrying capacity suggests that the threshold for the population size to persist 100 years required 113 animals,and 472 animals are required to persist 500 years.Therefore,we recommend establishing an ex situ reserve network to guarantee the minimum 100-year carrying capacity.To ensure the long-term population viability,we suggest establishing two in situ reserve zones in two lakes and their surrounding reserves to meet a minimum 500-year carrying capacity.In addition,measures to avoid further habitat fragmentation should be priority.展开更多
Reproductive hormones in serum concentrations of progesterone,estradiol,and testosterone in female Indo-Pacific bottlenose dolphins(Tursiops aduncus,n=12)housed in Ocean Park Hong Kong were investigated in the present...Reproductive hormones in serum concentrations of progesterone,estradiol,and testosterone in female Indo-Pacific bottlenose dolphins(Tursiops aduncus,n=12)housed in Ocean Park Hong Kong were investigated in the present study.Results showed that,onset of puberty of captive Indo-Pacific bottlenose dolphins was at 5 years while sexual maturity was at 6.Average serum progesterone concentrations in non-pregnant sexually mature individuals was 0.33(0.25–0.97)ng/mL(interquartile),significantly higher than in immature ones 0.26(0.25–0.38)ng/mL.This study found significant difference in serum estradiol concentrations between individuals at the onset of puberty(9.5±1.7 ng/mL,±SD)and not(below detection limit 9 pg/mL).A slightly seasonal breeding pattern,with progesterone values tend to be higher from February to October(0.38[0.25–1.07]ng/mL)was inferred.During pregnancy,serum progesterone concentrations range from 10.54±8.74 ng/mL(indexed month post-conception[IMPC]0)to 25.49±12.06 ng/mL(IMPC 2),and display a bimodal pattern with 2 peaks in early-(25.49±12.06 ng/mL,IMPC 2)and late-pregnancy(21.71±10.25 ng/mL,IMPC 12),respectively.Serum estradiol concentrations can seldom be detected in early-pregnancy and increase constantly in mid-(9.45±1.83 pg/mL)and late-pregnancy(11.88±3.81 pg/mL),with a spike(15.45±6.78 pg/mL)1 month prior to delivery.Serum testosterone concentrations elevate significantly in IMPC 7(0.36±0.10 ng/mL)compared to other months(0.16±0.10 ng/mL)of the year.The present study provides normal concentration profiles for some reproductive hormones in female Indo-Pacific bottlenose dolphins and can contribute to the breeding monitoring of this species.Also,our study would shed further light on the reproductive physiology of small cetaceans.展开更多
The stratification of blubber fatty acids(FAs)is a widely used strategy in marine mammals and can be influenced by many factors,including their diet,environmental temperature,and physiological status.There are 3 disti...The stratification of blubber fatty acids(FAs)is a widely used strategy in marine mammals and can be influenced by many factors,including their diet,environmental temperature,and physiological status.There are 3 distinct finless porpoise species/subspecies in Chinese coastal and inland waters in a wide range from 20°N to 40°N.The biochemical stratification of the blubbers of finless porpoises in different regions may provide valuable information for understanding their environmental adaptations.The FA compositions of 4 geographic populations of finless porpoise(FP)collected from the Bohai Gulf,East China Sea,South China Sea,and Yangtze River were therefore analyzed and compared.The blubber FA compositions of finless porpoises were dominated by∑MUFAs,followed by∑SFAs and∑PUFAs,and were generally consistent with those of other cetaceans.The blubber of finless porpoises was significantly stratified with increasing levels of∑MUFAs and decreasing levels of∑SFAs and∑PUFAs from the inner to the outer layers.The 3 marine populations shared more similarities in their FA compositions and stratifications compared to the freshwater porpoises,particularly regarding the PUFAs in the inner layers,which might have been mainly influenced by the diet compositions of marine and freshwater porpoises.Contrary to what was expected,in the 3 marine populations,the SFA and MUFA levels showed opposite correlations(negative and positive,respectively)with habitat temperatures,possibly indicating an adaptation mechanism in finless porpoises characterized by a trade-off between the insulation and fluidity properties of the blubber through the adjustment of the compositions and gradients of MUFAs and SFAs across the blubber depth in response to environmental temperature/latitude changes.展开更多
Blubber thickness(BT)has a seasonal pattern in most small cetaceans in temperate and polar regions,which may be a crucial adaptive mechanism in response to environmental temperature changes.However,BT and environmenta...Blubber thickness(BT)has a seasonal pattern in most small cetaceans in temperate and polar regions,which may be a crucial adaptive mechanism in response to environmental temperature changes.However,BT and environmental temperature correlations have never been tested experimentally in any cetacean species owing to logistical difficulties in the aquatic environment.The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis,YFP)is one of the smallest cetacean species worldwide,which exclusively inhabits the middle and lower regions of the Yangtze River in China.Here,we investigated BT variation patterns in YFPs and their relationship to environmental temperature changes using ultrasound imaging technology by longitudinally monitoring four YFPs in human care.We found that blubber was not evenly distributed in the skin of YFPs.BT increased along the craniocaudal axis from the head to the umbilical girth,and decreased towards the fluke,with relatively thicker blubber in the dorsal region than in the ventral and lateral regions.Significant negative correlations between BT and seasonal water temperature changes were observed in YFPs.However,different body regions display different sensitivities to seasonal temperature changes.The BT in the anal girth region exhibited noticeable seasonal changes.In contrast,the umbilical lateral and ventral regions showed relatively blunt seasonal changes,indicating different adaptive functions of the blubber in different regions.BT in the dorsal region decreased linearly with increasing water temperature.In the lateral and ventral regions,BT significantly changed with water temperature at a threshold of 18C.The YFPs had relatively thinner BT than similar-sized harbor porpoises that inhabit relatively high latitudes with much lower water temperatures.This further demonstrates the adaptive function of BT in response to environmental temperatures in small cetaceans.This study elucidates the seasonal pattern of BT variation in small cetaceans and provides insight into adaptation mechanisms of small cetaceans to temperature changes.展开更多
基金supported by the National Key R&D Program of China(2021YFD1200304).
文摘The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis,Pilleri&Gihr,1972;YFP)is an exclusively freshwater cetacean species inhabiting the Yangtze River and its connecting large lakes.As the primary line of defense in maintaining physiological equilibrium,the epidermis of the porpoise is expected to have undergone structural adaptations due to the shift from the marine to the freshwater environment.This study compared the microstructural and ultrastructural features of the epidermis of YFP and its marine counterpart,the East Asian finless porpoise(Neophocaena asiaeorientalis sunameri,Pilleri&Gihr,1975;EAFP).Microscopic structural observations and statistical analyses of the epidermal thickness demonstrated no significant differences in the cell structure or distribution between the two porpoise species.However,the epidermis of the YFP contained more abundant stratum basale cells.The outermost lipid stratum corneum exhibited a thinner cell layer with wider neutral lipid droplets to resist the passive entry of water molecules in the hypotonic environment.In contrast,for the EAFp,a more uniformly arranged stratum basale in the epidermis led to denser keratin fibers and robust desmosomes within each epidermal layer at the ultrastructural level.This tight arrangement of cells can reduce transepidermal water loss(TEWL)in an environment with higher osmotic pressure.In conclusion,the 2 finless porpoise species appear to employ different epidermal mechanisms to adapt to their distinct osmotic environments.The YFP appears to possess a"lipid waterproofing"epidermal structure,while the EAFP possesses a"thick and compact water-retaining"epidermal structure to copewithpotentialwaterloss.
基金supported by grants from National Natural Science Foundation of China(No.31430080)Ocean Park Conservation Foundation,Hong Kong(MM03_1920).
文摘Citizen science is a popular method for the long-term monitoring of the distribution of wild animals.The application of these methods in different species and environments still poses challenges,especially for aquatic animals.In this study,we investigated the distribution of the Bryde’s whale(Balaenoptera edeni)in the Beibu Gulf of China by using scientific boat-based surveys and citizen science approaches using 2 different methods of data collection.First,we built our mobile app(Whale Guard)and installed it on fishermen’s phones.Second,we used a popular instant messaging app(WeChat)to create an online fisherman community.We found that the mobile phone app collected far fewer reports(5 reports)than the online community group(42 reports,P<0.01).By using a variety of incentives,we maintained the fisherman’s community’s activity without significant user loss(P<0.01).We also found that the locations collected by social media applications in this study were consistent with observations from scientific boat-based transect surveys.The sightings distribution of Bryde’s whales differed from those in previous surveys in that they were present across larger areas.Social media apps reported that 69%of reports was confirmed by more than one person,whereas Whale Guard reports were much lower(0,P<0.001).Community-based citizen science can greatly contribute to the long-term monitoring of Bryde’s whales,and it has successfully overcome the challenges of data accessibility,accuracy,and fragmentation.Our study shows how to appropriately use citizen science in different community groups and community-based approaches make them useful for large baleen whale surveys.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23040403)the National Key Programme of Research and Development of Ministry of Science and Technology of China(No.2016YFC0503200)+1 种基金the National Natural Science Foundation of China(No.31430080)the Bureau of Science&Technology for Development of Chinese Academy of Sciences(No.ZSSD-004).
文摘The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),a critically endangered species,is the only cetacean species in the Yangtze River following the functional extinction of baiji(Lipotes vexillifer).To inform conservation actions,two important questions need to be addressed:what is the threshold value of survival rate,and what is the threshold value of population size?We calculate the instantaneous rate of population increase(¯r)for the Yangtze finless porpoise for various combinations of the calf and the non-calf survival rates.We also test the probability of extinction for different minimum carrying capacities for 100 and 500 years using a stable population model.The threshold value of the non-calf survival rate is never lower than 0.869,but current estimates from field data have been far below this threshold.Our model based on extinction probability and carrying capacity suggests that the threshold for the population size to persist 100 years required 113 animals,and 472 animals are required to persist 500 years.Therefore,we recommend establishing an ex situ reserve network to guarantee the minimum 100-year carrying capacity.To ensure the long-term population viability,we suggest establishing two in situ reserve zones in two lakes and their surrounding reserves to meet a minimum 500-year carrying capacity.In addition,measures to avoid further habitat fragmentation should be priority.
基金This study was supported by the National Natural Science Foundation of China(41806157)the Natural Science Foundation of Hainan Province(417213)the Youth Innovation Promotion Association of Chinese Academy of Sciences.
文摘Reproductive hormones in serum concentrations of progesterone,estradiol,and testosterone in female Indo-Pacific bottlenose dolphins(Tursiops aduncus,n=12)housed in Ocean Park Hong Kong were investigated in the present study.Results showed that,onset of puberty of captive Indo-Pacific bottlenose dolphins was at 5 years while sexual maturity was at 6.Average serum progesterone concentrations in non-pregnant sexually mature individuals was 0.33(0.25–0.97)ng/mL(interquartile),significantly higher than in immature ones 0.26(0.25–0.38)ng/mL.This study found significant difference in serum estradiol concentrations between individuals at the onset of puberty(9.5±1.7 ng/mL,±SD)and not(below detection limit 9 pg/mL).A slightly seasonal breeding pattern,with progesterone values tend to be higher from February to October(0.38[0.25–1.07]ng/mL)was inferred.During pregnancy,serum progesterone concentrations range from 10.54±8.74 ng/mL(indexed month post-conception[IMPC]0)to 25.49±12.06 ng/mL(IMPC 2),and display a bimodal pattern with 2 peaks in early-(25.49±12.06 ng/mL,IMPC 2)and late-pregnancy(21.71±10.25 ng/mL,IMPC 12),respectively.Serum estradiol concentrations can seldom be detected in early-pregnancy and increase constantly in mid-(9.45±1.83 pg/mL)and late-pregnancy(11.88±3.81 pg/mL),with a spike(15.45±6.78 pg/mL)1 month prior to delivery.Serum testosterone concentrations elevate significantly in IMPC 7(0.36±0.10 ng/mL)compared to other months(0.16±0.10 ng/mL)of the year.The present study provides normal concentration profiles for some reproductive hormones in female Indo-Pacific bottlenose dolphins and can contribute to the breeding monitoring of this species.Also,our study would shed further light on the reproductive physiology of small cetaceans.
基金This study was financially supported by the Ocean Park Conservation Foundation Hong Kong(MM01.2021).
文摘The stratification of blubber fatty acids(FAs)is a widely used strategy in marine mammals and can be influenced by many factors,including their diet,environmental temperature,and physiological status.There are 3 distinct finless porpoise species/subspecies in Chinese coastal and inland waters in a wide range from 20°N to 40°N.The biochemical stratification of the blubbers of finless porpoises in different regions may provide valuable information for understanding their environmental adaptations.The FA compositions of 4 geographic populations of finless porpoise(FP)collected from the Bohai Gulf,East China Sea,South China Sea,and Yangtze River were therefore analyzed and compared.The blubber FA compositions of finless porpoises were dominated by∑MUFAs,followed by∑SFAs and∑PUFAs,and were generally consistent with those of other cetaceans.The blubber of finless porpoises was significantly stratified with increasing levels of∑MUFAs and decreasing levels of∑SFAs and∑PUFAs from the inner to the outer layers.The 3 marine populations shared more similarities in their FA compositions and stratifications compared to the freshwater porpoises,particularly regarding the PUFAs in the inner layers,which might have been mainly influenced by the diet compositions of marine and freshwater porpoises.Contrary to what was expected,in the 3 marine populations,the SFA and MUFA levels showed opposite correlations(negative and positive,respectively)with habitat temperatures,possibly indicating an adaptation mechanism in finless porpoises characterized by a trade-off between the insulation and fluidity properties of the blubber through the adjustment of the compositions and gradients of MUFAs and SFAs across the blubber depth in response to environmental temperature/latitude changes.
基金financially supported by the National Key R&D Program of China,Grant No.2021YFD1200304.
文摘Blubber thickness(BT)has a seasonal pattern in most small cetaceans in temperate and polar regions,which may be a crucial adaptive mechanism in response to environmental temperature changes.However,BT and environmental temperature correlations have never been tested experimentally in any cetacean species owing to logistical difficulties in the aquatic environment.The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis,YFP)is one of the smallest cetacean species worldwide,which exclusively inhabits the middle and lower regions of the Yangtze River in China.Here,we investigated BT variation patterns in YFPs and their relationship to environmental temperature changes using ultrasound imaging technology by longitudinally monitoring four YFPs in human care.We found that blubber was not evenly distributed in the skin of YFPs.BT increased along the craniocaudal axis from the head to the umbilical girth,and decreased towards the fluke,with relatively thicker blubber in the dorsal region than in the ventral and lateral regions.Significant negative correlations between BT and seasonal water temperature changes were observed in YFPs.However,different body regions display different sensitivities to seasonal temperature changes.The BT in the anal girth region exhibited noticeable seasonal changes.In contrast,the umbilical lateral and ventral regions showed relatively blunt seasonal changes,indicating different adaptive functions of the blubber in different regions.BT in the dorsal region decreased linearly with increasing water temperature.In the lateral and ventral regions,BT significantly changed with water temperature at a threshold of 18C.The YFPs had relatively thinner BT than similar-sized harbor porpoises that inhabit relatively high latitudes with much lower water temperatures.This further demonstrates the adaptive function of BT in response to environmental temperatures in small cetaceans.This study elucidates the seasonal pattern of BT variation in small cetaceans and provides insight into adaptation mechanisms of small cetaceans to temperature changes.
