Life in the Antarctic is tough indeed.The extremely cold temperatures,fierce winds and vast stretches of ice make it a challenging environment for most life forms.But all these creatures come here because the Southern...Life in the Antarctic is tough indeed.The extremely cold temperatures,fierce winds and vast stretches of ice make it a challenging environment for most life forms.But all these creatures come here because the Southern Ocean is one of the richest oceans on Earth.When the continent separated from South America and moved south 30 million years ago,strong currents began to move in circles right around it.展开更多
A comprehensive risk assessment to evaluate the vulnerability of the nearshore cetaceans to increasing marine traffic is lacking.In this study,the risk to Indo-Pacific humpback dolphins(Sousa chinensis)in the main hab...A comprehensive risk assessment to evaluate the vulnerability of the nearshore cetaceans to increasing marine traffic is lacking.In this study,the risk to Indo-Pacific humpback dolphins(Sousa chinensis)in the main habitats in China was assessed based on a semiquantitative spatial vulnerability analysis.85%of the(sub)population which overlapped with the lanes of ferries and/or cargo vessels,with exposure scores of 1.23±0.31(calculated based on the proportion of sea routes that overlap the dolphin’s range).A combination of high exposure to the sea routes and sensitivity to marine traffic would render the(sub)populations to be highly vulnerable(EPRE:5.21 and XM:4.47).A low frequency of vessels and an awareness of the ecology assures a low vulnerability(SH:2.43,EZ:2.73).Uncertainty scores were commonly lower for the higher vulnerable populations,and higher for the lower vulnerable populations,suggesting additional field data and more monitoring are necessary.Six years of field data have been used to analyze the influences of various types of marine traffic on humpback dolphin behavior.Fishing and non-fishing vessels were significantly different(χ^(2)=65.19,p<0.01).The humpback dolphins were attracted by fishing vessels(83.1%)but avoided non-fishing vessels(95.2%).We recommend a management with seasonal and geographical constraints,to balance economic development and environmental conservation.展开更多
The aerodynamic forces and flowfield on a delta-wing Unmanned Aerial Vehicle(UAV)with specific airfoil are studied here.The leading-edge protuberances inspired from the flippers of the humpback whale is introduced in ...The aerodynamic forces and flowfield on a delta-wing Unmanned Aerial Vehicle(UAV)with specific airfoil are studied here.The leading-edge protuberances inspired from the flippers of the humpback whale is introduced in present work to watch its effect on stall delaying and drag reduction.Two installing factors,which are amplitude and wavelength of the protuberances,are considered to study the interaction of leading-edge variation and de-tached vortex.Three changes in both amplitude and wavelength are investigated herein.Generally,the modified models have larger stall angle of attack than that of the baseline model;the difference exists in the attainable lift coefficient and drag reduction.展开更多
The Hawaiian Islands, and particularly the Maui 4-island region, are a critical breeding and calving habitat for humpback whales (Megaptera novaeangliae) belonging to the Hawaii distinct population segment. Our aims w...The Hawaiian Islands, and particularly the Maui 4-island region, are a critical breeding and calving habitat for humpback whales (Megaptera novaeangliae) belonging to the Hawaii distinct population segment. Our aims were to test the use of platforms-of-opportunity to determine trends in mother-calf pod use of the region and to present opportunistic platforms as an alternative method of long-term, cross-seasonal monitoring. Data were collected from whale watching vessels over a 4-year period and analyzed using occupancy models to determine the probability of habitat use of pods with calves and pods without calves within the study area. Detection probability was influenced by survey effort and month for all pod types with detection of adult only pods further influenced by year. Pods with a calf showed a preference for shallow (<100 meters) low latitude waters (<20.7°N), while pods without a calf preferred deeper waters (>75 meters). Results presented here align with previous work, both in Hawaii and in other breeding grounds, which show a distinct segregation of mothers with a calf from other age-classes of humpback whales. The need for long-term continuous monitoring of cetacean populations is crucial to ensure species conservation. Data collected aboard platforms-of-opportunity, as presented here, provide important insight on humpback whale spatial and temporal distribution, which are essential for species protection and management.展开更多
In the frame of our long-term study of cetacean abundance and distribution in polar marine ecosystems begun in 1979, a drastic increase in the bowbead Balaena mysticetus North Atlantic ＂stock＂ was observed from 2005...In the frame of our long-term study of cetacean abundance and distribution in polar marine ecosystems begun in 1979, a drastic increase in the bowbead Balaena mysticetus North Atlantic ＂stock＂ was observed from 2005 on, by a factor 30 and more： from 0.0002 per count between 1979 and 2003 （one individual, n=5430 cotmts） to 0.06 per count from 2005 to 2014 （34 individuals, n=6000 counts）; the most significant part of the increase occurred from 2007 on. Other large whale species （Mysticeti） showed a similar pattern, mainly blue Balaenoptera musculus, humpback Megaptera novaeangliae and fin whales Balaenoptera physalus. This large and abrupt increase cannot logically be due to population growth, nor to survival of a hidden ＂relic＂ population, nor to a changing geographical distribution within the European Arctic, taking into account the importance of the coverage during this study. Our interpretation is that individuals passed through the Northwest and/or Northeast Passages from the larger Pacific stock into the almost depleted North Atlantic populations coinciding with a period of very low ice coverage -- at the time the lowest ever recorded. In contrast, no clear evolution was detected neither for sperm whale Physeter macrocephalus nor for Minke whale Balaenoptera acusrostrata.展开更多
As ecologically fragile areas,coastal zones are affected by both anthropogenic activities and climate change.However,the impacts of these factors on large nearshore mammals,such as Indo-Pacific humpback dolphins(IPHDs...As ecologically fragile areas,coastal zones are affected by both anthropogenic activities and climate change.However,the impacts of these factors on large nearshore mammals,such as Indo-Pacific humpback dolphins(IPHDs,Sousa chinensis),are poorly understood.Here,modeling revealed that the suitable habitats of IPHDs are affected mainly by the sea surface temperature(SST),and the habitat suitability decreases as the distance to the nearest coastline increases.In addition,anthropogenic activities involving demersal fishing,contamination and shipping have narrowed IPHD habitats and reduced the habitat suitability.We found that climate change will further narrow suitable habitats located farther than 7 km from coastlines and trigger habitat losses in the eastern Taiwan Strait by 2090-2100 under the Representative Concentration Pathway(RCP)8.5 scenario.The projected decreases in habitat suitability and area emphasize the urgency of establishing connected marine protected areas(MPAs)while considering climate change,intergovernmental cooperation,and public involvement.展开更多
Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean study.Understanding these ranges facilitates identification of...Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean study.Understanding these ranges facilitates identification of resource use and conservation.Fin and humpback whales occur in Antarctica during the austral summer,but information regarding their home ranges is limited.Using opportunistically collected whale sighting data from eight consecutive summer seasons spanning 2010–2017,we approximate the home ranges of humpback and fin whales around Drake Passage(DRA),West of Antarctic Peninsula(WAP),South Shetland Islands(SSI),an area northwest of the Weddell Sea(WED),and around the South Orkney Islands(SOI).Approximate home ranges are identified using Kernel Density Estimation(KDE).Most fin whales occurred north and northwest of the SOI,which suggests that waters near these islands support concentrations of this species.Most humpback whales were observed around the SSI,but unlike fin whales,their distributions were highly variable in other areas.KDE suggests spatial segregation in areas where both species exist such as SOI,SSI,and WPA.Partial redundancy analysis(pRDA)suggests that the distributions of these species are more affected by spatial variables(latitude,longitude)than by local scale variables such as sea surface temperature and depth.This study presents a visual approximation of the home ranges of fin and humpback whales,and identifies variation in the effects of space and environmental variables on the distributions of these whales at different spatial scales.展开更多
Humpback whales are migratory, spending summers in cooler, high-latitude waters and mating and calving in tropical and subtropical waters in 14 identified district population segments. It may be possible that the coas...Humpback whales are migratory, spending summers in cooler, high-latitude waters and mating and calving in tropical and subtropical waters in 14 identified district population segments. It may be possible that the coastal areas are infected with low pathogenic avian influenza (LPAI) during the release of infected humpback whale feces. Therefore, humpback whales can be an effective reservoir of the avian influenza virus (AIV) from the Poles to the Continents to spread AIV to coastal animals. Strong ultraviolet (UV) exposure amidst CO2 emission increase and minimal sunspot number might cause mutations of aquatic virus and humpback whale in the Antarctic and the Arctic. LPAI or highly pathogenic avian influenza (HPAI) is expressed in the Continents under appropriate environmental factors. Since penguins are birds while humpback whales are marine mammals, the humpback whales infected by the mutant virus might cause interspecies transmission to a new host with evolutionary changes. The migration pattern is seasonally similar between migratory bird and humpback whale except: 1) different species of bird versus whale, 2) different landing area of land versus coast, 3) similar infection means of bird feces versus humpback whale feces. The contribution of AIV transmission by whales was several times larger than that by migratory birds. Therefore, the routes of humpback whales should be considered to prevent AIV outbreaks in addition to the flyways of migratory birds. Humpback whale stranding (y) along the Atlantic Coast of the USA was correlated with CO2 emissions (x) to have y = 0.3515x + 18.595 (R2 = 0.4069) during 1992-2016 while y = 0.0652x + 4.5847, (R2 = 0.6128) during 2016-2018. AIV outbreak in 2010 (y) along the Atlantic Coast was also correlated with humpback whale stranding (2016-2018) (x) as y = 0.1387x + 6.8184 (R2 = 0.3966). Since AIV outbreak was linearly (R2 = 0.9967) correlated with the minimum sunspot number, it was postulated that the unusual mortality events of humpback whale stranding might be caused by an infected mutant virus in the Arctic. Consequently, the humpback whales were stranded along major CO2 producing Atlantic Coast States toward the winter habitat of the West Indies during the CO2 emissions and the minimal sunspot number with strong UV radiation. The stranded dead whales should be burned as soon as possible to prevent further deadly viral interspecies transmission of AIV by the coastal animals. Since CO2 emissions were increased in 2017 and the sunspot number was minimal at the end of 2018, serious numbers of whales are expected to be stranded at the Gulf of Maine, States of North Carolina, New York, and Virginia from November 2018 till April 2019. To save humpback whales from the unusual mortality event along the Atlantic Coast, the reduction of CO2 emissions is suggested by replacement of fossil fuels combustion plants with nuclear power plants along the Atlantic Coast of the USA.展开更多
Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly u...Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly understood. Hence, we examine the migratory timing of humpback whales in Okinawa that is one of their breeding ground, distinguishing the reproductive status (male, female, or female with a calf), group compositions (singleton, pair, or whales more than three) and group types (singer or competitive group) in order to assess the peak period of breeding activities. A total of 1192 days of photo-identification surveys were conducted from 1991 to 2012 and a total of 7366 humpback whales were sighted during the surveys. Among them, 1284 whales were sex-determined (848 males, 147 females and 289 females with a calf), 1138 singletons, 1416 pairs and 710 groups of more than three whales were observed. Females without calves tended to occur from late January to late February, which was the beginning of the breeding season and male-female pairs were observed most frequently during this period. The peak occurrence of competitive group which was considered a mating-related behavior group, formed by females and males, was also observed during this period. These results indicated that humpback whales peak mating period in Okinawa occurred between late January and late February. Females with a calf tended to increase from mid-February toward the end of the breeding season maintaining a high sighting per unit effort (SPUE) value in late March. We, therefore, suggested that the peak time of birthing and newborn care was probably that period in Okinawa. These findings extended our knowledge on the reproductive ecology of humpback whales in Okinawan waters.展开更多
The Indo–Pacific humpback dolphin(Sousa chinensis Osbeck,1765)is a threatened species inhabiting the waters of China.Despite being of conservation concern,the distribution and abundance of this species has not been c...The Indo–Pacific humpback dolphin(Sousa chinensis Osbeck,1765)is a threatened species inhabiting the waters of China.Despite being of conservation concern,the distribution and abundance of this species has not been comprehensively evaluated.From 1994 to 2008 we performed over 14000 km of line-transect surveys and adminis-tered over 700 questionnaires to collect basic information on the geographic range and likely abundance of Indo–Pacific humpback dolphins along the southern and eastern coasts of China.Through our study we were able to establish a reporting network of stranding and incidental catches for this species.Our quantitative data suggests that only 76 animals remain around Xiamen,39 in the Hepu Nature Reserve and 114 in the estuary of the Dafengjiang River.Qualitative data from local fishing people and government officials suggests that dolphins may exist year-round in waters off Ningde and Shantou.We found that wild populations of Sousa chinensis in this important region are clearly being affected by human disturbance and habitat deterioration,including underwater blasting,vessel collision,fishing,aquaculture and water pollution.Although some protected areas have been established and this species is protected under Chinese law,there remains virtually no protection for this animal.展开更多
中华白海豚(Sousa chinensis)是近岸海洋生态系统的旗舰物种和指示物种,但目前对该物种的分布范围了解仍然存在局限,许多未经调查的区域缺少基线信息。本研究在野外调查的基础上,结合卫星遥感数据,使用最大熵(MaxEnt)模型将调查点位映...中华白海豚(Sousa chinensis)是近岸海洋生态系统的旗舰物种和指示物种,但目前对该物种的分布范围了解仍然存在局限,许多未经调查的区域缺少基线信息。本研究在野外调查的基础上,结合卫星遥感数据,使用最大熵(MaxEnt)模型将调查点位映射至北部湾东北部近岸水域,预测了该水域中华白海豚的潜在适宜栖息地。环境变量的相关系数分析结果表明,叶绿素a浓度、离岸距离、海表温度、水体漫衰减系数和水深等5个环境变量之间相关性较低,用于最终的分析。模型运行结果显示曲线下面积(area under curve,AUC)为0.991,模型拟合度较好。刀切法测试结果表明叶绿素a和离岸距离是影响该水域中华白海豚分布的主要因素,而海表温度、水体漫衰减系数和水深的影响则相对较小,并且环境因子的影响均有最适区间。在北部湾东北部水域,大部分水域都是中华白海豚的潜在适宜栖息地,但高适生区主要零散分布在沙田-草潭水域、三娘湾水域以及北海市南部的冠头岭水域,表明当前该物种栖息地存在破碎化。目前,主要针对前两块高适生区开展了调查研究,其他水域的基线信息较为空白。因此,未来应扩大中华白海豚的调查范围,确认这些水域是否有中华白海豚的分布,并采取相应措施进行保护,如推动建立保护区、纳入海岸带综合管理、开展生态修复、推动信息共享等。展开更多
The mammalian intestinal microbiome is critical for host health and disease resistance.However,the cetacean intestinal microbiota remains relatively unexplored.By using high-throughput 16S rRNA gene sequencing,we anal...The mammalian intestinal microbiome is critical for host health and disease resistance.However,the cetacean intestinal microbiota remains relatively unexplored.By using high-throughput 16S rRNA gene sequencing,we analyzed intestinal bacterial samples from an Indo-pacific humpback dolphin(Sousa chinensis)stranded near the Pearl River Estuary in China.The samples included 3 anatomical regions(foregut,midgut,and rectum)and 2 anatomical locations(content and mucus).Our analyses revealed that the dolphin intestinal bacteria contained 139 operational taxonomic units(OTUs),dominated at the phyla level by Firmicutes(47.05%in the content;94.77%in the mucus),followed by Bacteroidetes(23.63%in the content;1.58%in the mucus)and Gammaproteobacteria(14.82%in the content;2.05%in the mucus).The intestinal bacteria had a small core community(15 OTUs,accounting for 99.74%of the reads),some of which could be potentially pathogenic to both human and dolphins.As an alternative to sampling the dolphin intestinal bacteria,fecal sampling could be used.Additionally,function potentials such as,xenobiotics biodegradation,beta-lactam resistance,and human disease-related pathways,were detected in the dolphin intestinal bacteria.These findings provide the first baseline knowledge of the intestinal microbiome of the Indo-Pacific humpback dolphin,which may offer new insights into cetacean conservation by using microbial surveillance.展开更多
Geographic variations in the dolphin whistles could be useful in assessing association and isolation among populations.Whistle of free-ranging Indo-Pacific humpback dolphins(Sousa chinensis)among the Pearl River Estua...Geographic variations in the dolphin whistles could be useful in assessing association and isolation among populations.Whistle of free-ranging Indo-Pacific humpback dolphins(Sousa chinensis)among the Pearl River Estuary(PRE),Leizhou Bei(LZB)and Sanniang Bay(SNB)populations were investigated.A total of 2850 whistles with legible fundamental contour were extracted and 15 acoustic parameters were measured.Contrary to SNB,PRE and LZB had the same relative proportion of tonal type compositions with flat and sine representing the most frequent types.The generalized linear model analysis showed significant acoustic difference among populations and tonal types.All frequency parameters in SNB were significantly higher than those in PRE and LZB,where no significant variation was observed in most of the parameters either at the population level or within each tonal type.Canonical discriminant functions analysis showed a smaller difference between PRE and LZB than between PRE and SNB and between LZB and SNB.Compared with previous recordings,recent recordings demonstrated a consistent pattern of becoming higher in whistle frequency parameters in both LZB and SNB populations,suggesting that noise pollution in LZB and SNB increasing with time according to the acoustic niche hypothesis.Dolphin whistle’s geographic variations could be shaped by the combined function of the geographical barrier function of the Qiongzhou strait and local ambient noise.Considering the isolated condition and the relatively smaller population size of the humpback dolphin in the SNB,more effective and proactive conservation actions should be taken to prevent the extinction of small populations.展开更多
Humpback dolphins(Sousa spp.)are obligate shallow-water and resident species,and they typically live in fission–fusion societies composed of small-sized groups with changeable membership.However,we have scant knowled...Humpback dolphins(Sousa spp.)are obligate shallow-water and resident species,and they typically live in fission–fusion societies composed of small-sized groups with changeable membership.However,we have scant knowledge of their behavioral ecology,starting with potential factors influencing inter-population variability of their group sizes.Here,we compiled a new global dataset of humpback dolphin group sizes based on 150 published records.Our data indicated an inter-specific consistency of group-living strategy among the 4 species in the Sousa genus,as these species preferred living in small-sized groups with a mean size of mostly no more than 10,a minimum size of single individual or small pairs,and a maximum size of several tens or≈100.In addition,we clearly showed the geographic variations in group sizes of humpback dolphins at a global scale.We found that the geographic variations in humpback dolphin group sizes were primarily associated with the latitude,sea surface temperature,and abundance.To conclude,our findings provide insights into social dynamics and socioecological trade-offs of humpback dolphins,and help better understand how these resident animals adapted to their shallow-water habitats from the perspectives of biogeography and socioecology.展开更多
Accurate diet identification of top predators is crucial to fully understand their ecological roles.Compared to terrestrial animals,gathering dietary information from cetaceans is notoriously difficult.Here,we applied a...Accurate diet identification of top predators is crucial to fully understand their ecological roles.Compared to terrestrial animals,gathering dietary information from cetaceans is notoriously difficult.Here,we applied a multilocus metabarcoding approach to investigate the diet of vulnerable Indo-Pacific humpback dolphins and Indo-Pacificfinless porpoises from the Pearl River Estuary(PRE),China.Our analyses identified 21 preyfish species from the 42 humpback dolphin stomachs,as well as 10 species offish and 1 species of cephalopod from the 13finless porpoise stomachs.All of the taxa were assigned to the species level,highlighting that the multimarker approach could facilitate species identification.Most of the prey species were small-and medium-sizedfishes that primarily fed on zooplankton.The calculated similarity index revealed a moderated dietary overlap between the 2 cetaceans,presumably due to the feeding of the 2 predators in association withfishing vessels in the PRE.A more diverse diet was observed in humpback dolphins in the closedfishing season compared to thefishing season,implying the influence on the dolphin diet due to the availability of commercialfishery resources.However,according to the results of species rarefaction curves,ourfindings on the feeding habits of the 2 cetaceans are still limited by insufficient sample size and therefore should be interpreted with caution.This study represents afirst attempt to apply the multilocus DNA metabarcoding technique in the diet analysis of small cetaceans,although more efforts are needed to improve this type of analysis.展开更多
文摘Life in the Antarctic is tough indeed.The extremely cold temperatures,fierce winds and vast stretches of ice make it a challenging environment for most life forms.But all these creatures come here because the Southern Ocean is one of the richest oceans on Earth.When the continent separated from South America and moved south 30 million years ago,strong currents began to move in circles right around it.
基金supported by the National Key Research and Development Program of China (No.2022 YFF1301603)the Guangdong Basic and Applied Basic Research Foundation (No.2021A1515011467)in China+2 种基金the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai),China (Nos.311020003 and 311021004)the National Natural Science Foundation of China (No.32201290)the 71st batch of China Postdoctoral Science Funding (No.2022M713560)。
文摘A comprehensive risk assessment to evaluate the vulnerability of the nearshore cetaceans to increasing marine traffic is lacking.In this study,the risk to Indo-Pacific humpback dolphins(Sousa chinensis)in the main habitats in China was assessed based on a semiquantitative spatial vulnerability analysis.85%of the(sub)population which overlapped with the lanes of ferries and/or cargo vessels,with exposure scores of 1.23±0.31(calculated based on the proportion of sea routes that overlap the dolphin’s range).A combination of high exposure to the sea routes and sensitivity to marine traffic would render the(sub)populations to be highly vulnerable(EPRE:5.21 and XM:4.47).A low frequency of vessels and an awareness of the ecology assures a low vulnerability(SH:2.43,EZ:2.73).Uncertainty scores were commonly lower for the higher vulnerable populations,and higher for the lower vulnerable populations,suggesting additional field data and more monitoring are necessary.Six years of field data have been used to analyze the influences of various types of marine traffic on humpback dolphin behavior.Fishing and non-fishing vessels were significantly different(χ^(2)=65.19,p<0.01).The humpback dolphins were attracted by fishing vessels(83.1%)but avoided non-fishing vessels(95.2%).We recommend a management with seasonal and geographical constraints,to balance economic development and environmental conservation.
基金support from China Postdoctoral Science Foundation(No.2017M623184)。
文摘The aerodynamic forces and flowfield on a delta-wing Unmanned Aerial Vehicle(UAV)with specific airfoil are studied here.The leading-edge protuberances inspired from the flippers of the humpback whale is introduced in present work to watch its effect on stall delaying and drag reduction.Two installing factors,which are amplitude and wavelength of the protuberances,are considered to study the interaction of leading-edge variation and de-tached vortex.Three changes in both amplitude and wavelength are investigated herein.Generally,the modified models have larger stall angle of attack than that of the baseline model;the difference exists in the attainable lift coefficient and drag reduction.
文摘The Hawaiian Islands, and particularly the Maui 4-island region, are a critical breeding and calving habitat for humpback whales (Megaptera novaeangliae) belonging to the Hawaii distinct population segment. Our aims were to test the use of platforms-of-opportunity to determine trends in mother-calf pod use of the region and to present opportunistic platforms as an alternative method of long-term, cross-seasonal monitoring. Data were collected from whale watching vessels over a 4-year period and analyzed using occupancy models to determine the probability of habitat use of pods with calves and pods without calves within the study area. Detection probability was influenced by survey effort and month for all pod types with detection of adult only pods further influenced by year. Pods with a calf showed a preference for shallow (<100 meters) low latitude waters (<20.7°N), while pods without a calf preferred deeper waters (>75 meters). Results presented here align with previous work, both in Hawaii and in other breeding grounds, which show a distinct segregation of mothers with a calf from other age-classes of humpback whales. The need for long-term continuous monitoring of cetacean populations is crucial to ensure species conservation. Data collected aboard platforms-of-opportunity, as presented here, provide important insight on humpback whale spatial and temporal distribution, which are essential for species protection and management.
文摘In the frame of our long-term study of cetacean abundance and distribution in polar marine ecosystems begun in 1979, a drastic increase in the bowbead Balaena mysticetus North Atlantic ＂stock＂ was observed from 2005 on, by a factor 30 and more： from 0.0002 per count between 1979 and 2003 （one individual, n=5430 cotmts） to 0.06 per count from 2005 to 2014 （34 individuals, n=6000 counts）; the most significant part of the increase occurred from 2007 on. Other large whale species （Mysticeti） showed a similar pattern, mainly blue Balaenoptera musculus, humpback Megaptera novaeangliae and fin whales Balaenoptera physalus. This large and abrupt increase cannot logically be due to population growth, nor to survival of a hidden ＂relic＂ population, nor to a changing geographical distribution within the European Arctic, taking into account the importance of the coverage during this study. Our interpretation is that individuals passed through the Northwest and/or Northeast Passages from the larger Pacific stock into the almost depleted North Atlantic populations coinciding with a period of very low ice coverage -- at the time the lowest ever recorded. In contrast, no clear evolution was detected neither for sperm whale Physeter macrocephalus nor for Minke whale Balaenoptera acusrostrata.
基金supported by the National Natural Science Founda-tion of China(NSFC)(Grant No.41901349)Marine Economy Develop-ment Foundation of Guangdong Province(Grant No.GDNRC[2022]21)+1 种基金Basic Scientific Research Program of National Nonprofit Research Insti-tutes(Grant No.ZX2022QT025)the Startup Foundation for Tal-ented Scholars in South China Normal University(Grant No.8S0472).
文摘As ecologically fragile areas,coastal zones are affected by both anthropogenic activities and climate change.However,the impacts of these factors on large nearshore mammals,such as Indo-Pacific humpback dolphins(IPHDs,Sousa chinensis),are poorly understood.Here,modeling revealed that the suitable habitats of IPHDs are affected mainly by the sea surface temperature(SST),and the habitat suitability decreases as the distance to the nearest coastline increases.In addition,anthropogenic activities involving demersal fishing,contamination and shipping have narrowed IPHD habitats and reduced the habitat suitability.We found that climate change will further narrow suitable habitats located farther than 7 km from coastlines and trigger habitat losses in the eastern Taiwan Strait by 2090-2100 under the Representative Concentration Pathway(RCP)8.5 scenario.The projected decreases in habitat suitability and area emphasize the urgency of establishing connected marine protected areas(MPAs)while considering climate change,intergovernmental cooperation,and public involvement.
基金This work was conducted with logistical and financial support of the Instituto Antártico Argentino.
文摘Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean study.Understanding these ranges facilitates identification of resource use and conservation.Fin and humpback whales occur in Antarctica during the austral summer,but information regarding their home ranges is limited.Using opportunistically collected whale sighting data from eight consecutive summer seasons spanning 2010–2017,we approximate the home ranges of humpback and fin whales around Drake Passage(DRA),West of Antarctic Peninsula(WAP),South Shetland Islands(SSI),an area northwest of the Weddell Sea(WED),and around the South Orkney Islands(SOI).Approximate home ranges are identified using Kernel Density Estimation(KDE).Most fin whales occurred north and northwest of the SOI,which suggests that waters near these islands support concentrations of this species.Most humpback whales were observed around the SSI,but unlike fin whales,their distributions were highly variable in other areas.KDE suggests spatial segregation in areas where both species exist such as SOI,SSI,and WPA.Partial redundancy analysis(pRDA)suggests that the distributions of these species are more affected by spatial variables(latitude,longitude)than by local scale variables such as sea surface temperature and depth.This study presents a visual approximation of the home ranges of fin and humpback whales,and identifies variation in the effects of space and environmental variables on the distributions of these whales at different spatial scales.
文摘Humpback whales are migratory, spending summers in cooler, high-latitude waters and mating and calving in tropical and subtropical waters in 14 identified district population segments. It may be possible that the coastal areas are infected with low pathogenic avian influenza (LPAI) during the release of infected humpback whale feces. Therefore, humpback whales can be an effective reservoir of the avian influenza virus (AIV) from the Poles to the Continents to spread AIV to coastal animals. Strong ultraviolet (UV) exposure amidst CO2 emission increase and minimal sunspot number might cause mutations of aquatic virus and humpback whale in the Antarctic and the Arctic. LPAI or highly pathogenic avian influenza (HPAI) is expressed in the Continents under appropriate environmental factors. Since penguins are birds while humpback whales are marine mammals, the humpback whales infected by the mutant virus might cause interspecies transmission to a new host with evolutionary changes. The migration pattern is seasonally similar between migratory bird and humpback whale except: 1) different species of bird versus whale, 2) different landing area of land versus coast, 3) similar infection means of bird feces versus humpback whale feces. The contribution of AIV transmission by whales was several times larger than that by migratory birds. Therefore, the routes of humpback whales should be considered to prevent AIV outbreaks in addition to the flyways of migratory birds. Humpback whale stranding (y) along the Atlantic Coast of the USA was correlated with CO2 emissions (x) to have y = 0.3515x + 18.595 (R2 = 0.4069) during 1992-2016 while y = 0.0652x + 4.5847, (R2 = 0.6128) during 2016-2018. AIV outbreak in 2010 (y) along the Atlantic Coast was also correlated with humpback whale stranding (2016-2018) (x) as y = 0.1387x + 6.8184 (R2 = 0.3966). Since AIV outbreak was linearly (R2 = 0.9967) correlated with the minimum sunspot number, it was postulated that the unusual mortality events of humpback whale stranding might be caused by an infected mutant virus in the Arctic. Consequently, the humpback whales were stranded along major CO2 producing Atlantic Coast States toward the winter habitat of the West Indies during the CO2 emissions and the minimal sunspot number with strong UV radiation. The stranded dead whales should be burned as soon as possible to prevent further deadly viral interspecies transmission of AIV by the coastal animals. Since CO2 emissions were increased in 2017 and the sunspot number was minimal at the end of 2018, serious numbers of whales are expected to be stranded at the Gulf of Maine, States of North Carolina, New York, and Virginia from November 2018 till April 2019. To save humpback whales from the unusual mortality event along the Atlantic Coast, the reduction of CO2 emissions is suggested by replacement of fossil fuels combustion plants with nuclear power plants along the Atlantic Coast of the USA.
文摘Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly understood. Hence, we examine the migratory timing of humpback whales in Okinawa that is one of their breeding ground, distinguishing the reproductive status (male, female, or female with a calf), group compositions (singleton, pair, or whales more than three) and group types (singer or competitive group) in order to assess the peak period of breeding activities. A total of 1192 days of photo-identification surveys were conducted from 1991 to 2012 and a total of 7366 humpback whales were sighted during the surveys. Among them, 1284 whales were sex-determined (848 males, 147 females and 289 females with a calf), 1138 singletons, 1416 pairs and 710 groups of more than three whales were observed. Females without calves tended to occur from late January to late February, which was the beginning of the breeding season and male-female pairs were observed most frequently during this period. The peak occurrence of competitive group which was considered a mating-related behavior group, formed by females and males, was also observed during this period. These results indicated that humpback whales peak mating period in Okinawa occurred between late January and late February. Females with a calf tended to increase from mid-February toward the end of the breeding season maintaining a high sighting per unit effort (SPUE) value in late March. We, therefore, suggested that the peak time of birthing and newborn care was probably that period in Okinawa. These findings extended our knowledge on the reproductive ecology of humpback whales in Okinawan waters.
基金supported by a key project of the National Natural Science Foundation of China(Grant 30830016)the Program for New Century Excellent Talents in University(NCET-07-0445)+3 种基金the Ministry of Education of Chinathe Specialized Research Fund for the Doctoral Program of Higher Education(SRFDP 20060319002)the Ministry of Education of China,the Major Project for Basic Researches of Jiangsu Province University(07KJA18016)Key Project in the National Science&Technology Pillar Program during the Eleventh Five-Year Plan Period(2007BAC03A08).
文摘The Indo–Pacific humpback dolphin(Sousa chinensis Osbeck,1765)is a threatened species inhabiting the waters of China.Despite being of conservation concern,the distribution and abundance of this species has not been comprehensively evaluated.From 1994 to 2008 we performed over 14000 km of line-transect surveys and adminis-tered over 700 questionnaires to collect basic information on the geographic range and likely abundance of Indo–Pacific humpback dolphins along the southern and eastern coasts of China.Through our study we were able to establish a reporting network of stranding and incidental catches for this species.Our quantitative data suggests that only 76 animals remain around Xiamen,39 in the Hepu Nature Reserve and 114 in the estuary of the Dafengjiang River.Qualitative data from local fishing people and government officials suggests that dolphins may exist year-round in waters off Ningde and Shantou.We found that wild populations of Sousa chinensis in this important region are clearly being affected by human disturbance and habitat deterioration,including underwater blasting,vessel collision,fishing,aquaculture and water pollution.Although some protected areas have been established and this species is protected under Chinese law,there remains virtually no protection for this animal.
文摘中华白海豚(Sousa chinensis)是近岸海洋生态系统的旗舰物种和指示物种,但目前对该物种的分布范围了解仍然存在局限,许多未经调查的区域缺少基线信息。本研究在野外调查的基础上,结合卫星遥感数据,使用最大熵(MaxEnt)模型将调查点位映射至北部湾东北部近岸水域,预测了该水域中华白海豚的潜在适宜栖息地。环境变量的相关系数分析结果表明,叶绿素a浓度、离岸距离、海表温度、水体漫衰减系数和水深等5个环境变量之间相关性较低,用于最终的分析。模型运行结果显示曲线下面积(area under curve,AUC)为0.991,模型拟合度较好。刀切法测试结果表明叶绿素a和离岸距离是影响该水域中华白海豚分布的主要因素,而海表温度、水体漫衰减系数和水深的影响则相对较小,并且环境因子的影响均有最适区间。在北部湾东北部水域,大部分水域都是中华白海豚的潜在适宜栖息地,但高适生区主要零散分布在沙田-草潭水域、三娘湾水域以及北海市南部的冠头岭水域,表明当前该物种栖息地存在破碎化。目前,主要针对前两块高适生区开展了调查研究,其他水域的基线信息较为空白。因此,未来应扩大中华白海豚的调查范围,确认这些水域是否有中华白海豚的分布,并采取相应措施进行保护,如推动建立保护区、纳入海岸带综合管理、开展生态修复、推动信息共享等。
基金This research was supported by grants from the Bu-reau of Science&Technology for Development,the Chinese Academy of Sciences(No.ZSSD-004)the National Key Programme of Research and Develop-ment of Ministry of Science and Technology of China(2016YFC0503200).
文摘The mammalian intestinal microbiome is critical for host health and disease resistance.However,the cetacean intestinal microbiota remains relatively unexplored.By using high-throughput 16S rRNA gene sequencing,we analyzed intestinal bacterial samples from an Indo-pacific humpback dolphin(Sousa chinensis)stranded near the Pearl River Estuary in China.The samples included 3 anatomical regions(foregut,midgut,and rectum)and 2 anatomical locations(content and mucus).Our analyses revealed that the dolphin intestinal bacteria contained 139 operational taxonomic units(OTUs),dominated at the phyla level by Firmicutes(47.05%in the content;94.77%in the mucus),followed by Bacteroidetes(23.63%in the content;1.58%in the mucus)and Gammaproteobacteria(14.82%in the content;2.05%in the mucus).The intestinal bacteria had a small core community(15 OTUs,accounting for 99.74%of the reads),some of which could be potentially pathogenic to both human and dolphins.As an alternative to sampling the dolphin intestinal bacteria,fecal sampling could be used.Additionally,function potentials such as,xenobiotics biodegradation,beta-lactam resistance,and human disease-related pathways,were detected in the dolphin intestinal bacteria.These findings provide the first baseline knowledge of the intestinal microbiome of the Indo-Pacific humpback dolphin,which may offer new insights into cetacean conservation by using microbial surveillance.
基金This research was supported by grants from the National Natural Science Foundation of China(Grant No.41806197)Ocean Park Conservation Foundation of Hong Kong(AW011920)Chinese white dolphin monitoring program of Guangzhou harbor deepwater navigation channel widening project(Grant No.HTYXJC)to Zhitao Wang.
文摘Geographic variations in the dolphin whistles could be useful in assessing association and isolation among populations.Whistle of free-ranging Indo-Pacific humpback dolphins(Sousa chinensis)among the Pearl River Estuary(PRE),Leizhou Bei(LZB)and Sanniang Bay(SNB)populations were investigated.A total of 2850 whistles with legible fundamental contour were extracted and 15 acoustic parameters were measured.Contrary to SNB,PRE and LZB had the same relative proportion of tonal type compositions with flat and sine representing the most frequent types.The generalized linear model analysis showed significant acoustic difference among populations and tonal types.All frequency parameters in SNB were significantly higher than those in PRE and LZB,where no significant variation was observed in most of the parameters either at the population level or within each tonal type.Canonical discriminant functions analysis showed a smaller difference between PRE and LZB than between PRE and SNB and between LZB and SNB.Compared with previous recordings,recent recordings demonstrated a consistent pattern of becoming higher in whistle frequency parameters in both LZB and SNB populations,suggesting that noise pollution in LZB and SNB increasing with time according to the acoustic niche hypothesis.Dolphin whistle’s geographic variations could be shaped by the combined function of the geographical barrier function of the Qiongzhou strait and local ambient noise.Considering the isolated condition and the relatively smaller population size of the humpback dolphin in the SNB,more effective and proactive conservation actions should be taken to prevent the extinction of small populations.
基金This study was financially supported by the Major Science and Technology Project in Hainan province(ZDKJ2016009-1-1)the National Natural Science Foundation of China(41306169,41406182,and 41422604)+2 种基金the Ocean Park Conservation Foundation of Hong Kong(AW02-1920)the Chinese White Dolphin Conservation Action Project of Ministry of Agriculture and Rural of People’s Republic of China(Y760091HT1)the Biodiversity Investigation,Observation and Assessment Program of Ministry of Ecology and Environment of China(2019-2023).
文摘Humpback dolphins(Sousa spp.)are obligate shallow-water and resident species,and they typically live in fission–fusion societies composed of small-sized groups with changeable membership.However,we have scant knowledge of their behavioral ecology,starting with potential factors influencing inter-population variability of their group sizes.Here,we compiled a new global dataset of humpback dolphin group sizes based on 150 published records.Our data indicated an inter-specific consistency of group-living strategy among the 4 species in the Sousa genus,as these species preferred living in small-sized groups with a mean size of mostly no more than 10,a minimum size of single individual or small pairs,and a maximum size of several tens or≈100.In addition,we clearly showed the geographic variations in group sizes of humpback dolphins at a global scale.We found that the geographic variations in humpback dolphin group sizes were primarily associated with the latitude,sea surface temperature,and abundance.To conclude,our findings provide insights into social dynamics and socioecological trade-offs of humpback dolphins,and help better understand how these resident animals adapted to their shallow-water habitats from the perspectives of biogeography and socioecology.
基金supported by the Natural Science Foundation of Guangdong Province(2017A030308005)in Chinathe National Natural Science Foundation of China(41576128,42007225)+4 种基金Guangdong Basic and Applied Basic Research Foundation(2020A1515010910)in ChinaChina Postdoctoral Science Foundation(2019M653153)Fundamental Research Funds for the Central Universities(19lgpy95)Ocean Park Conservation Foundation of Hong Kong(MM01.1718)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(311021004,311020003).
文摘Accurate diet identification of top predators is crucial to fully understand their ecological roles.Compared to terrestrial animals,gathering dietary information from cetaceans is notoriously difficult.Here,we applied a multilocus metabarcoding approach to investigate the diet of vulnerable Indo-Pacific humpback dolphins and Indo-Pacificfinless porpoises from the Pearl River Estuary(PRE),China.Our analyses identified 21 preyfish species from the 42 humpback dolphin stomachs,as well as 10 species offish and 1 species of cephalopod from the 13finless porpoise stomachs.All of the taxa were assigned to the species level,highlighting that the multimarker approach could facilitate species identification.Most of the prey species were small-and medium-sizedfishes that primarily fed on zooplankton.The calculated similarity index revealed a moderated dietary overlap between the 2 cetaceans,presumably due to the feeding of the 2 predators in association withfishing vessels in the PRE.A more diverse diet was observed in humpback dolphins in the closedfishing season compared to thefishing season,implying the influence on the dolphin diet due to the availability of commercialfishery resources.However,according to the results of species rarefaction curves,ourfindings on the feeding habits of the 2 cetaceans are still limited by insufficient sample size and therefore should be interpreted with caution.This study represents afirst attempt to apply the multilocus DNA metabarcoding technique in the diet analysis of small cetaceans,although more efforts are needed to improve this type of analysis.
