Finless porpoises(FPs)serve as flagship species and key ecological indicators for assessing environmental quality.However,FPs are challenging to survey due to their elusive behavior and lack of distinctive features.St...Finless porpoises(FPs)serve as flagship species and key ecological indicators for assessing environmental quality.However,FPs are challenging to survey due to their elusive behavior and lack of distinctive features.Stranding and sighting events offer essential information on species diversity,distribution patterns,and potential threats.In this study,records from 1986 to 2023 were analyzed to assess the temporal and spatial distribution patterns of FP strandings and sightings in the Qiantang River Estuary,China.Results show an increase in the number of recorded events over time.Seasonal variations were evident,with a peak in strandings and sightings occurring in late winter.The frequency of records was higher during spring and moderate tides compared to neap tides,particularly in hydrologically normal years.Rapidly receding tides and sediment accumulation appear to restrict the activity space of FPs,thereby increasing the frequency of these events.Localized conditions associated with stranding and sighting events were classified into four categories:bifurcation zones,confluence zones,separation zones,and deep channels adjacent to concave banks.Deep channels,which are optimal for shipping,also elevate the risk of FP strandings.These findings offer valuable insights for the development and design of conservation strategies tailored to the needs of FPs in estuarine environments.展开更多
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
The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)is distributed in the main stream of the middle and lower reaches of the Yangtze River,as well as in Dongting and Poyang lakes.Currently,the mos...The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)is distributed in the main stream of the middle and lower reaches of the Yangtze River,as well as in Dongting and Poyang lakes.Currently,the most crucial conservation approach involves the establishment and management of both in-situ and ex-situ nature reserves.Since the 1990s,seven nature reserves have been established in the middle and lower reaches of the Yangtze River,covering nearly one-third of its main stream.Additionally,two nature reserves,one in the Dongting Lake and another in the Poyang Lake,have been set up;and three ex-situ nature reserves have been established in three oxbows respectively in Hunan,Hubei,and Anhui provinces.Through measures such as improving the ecological environment quality within the reserves,regulating human activities,and conducting continuous monitoring,the finless porpoise population showed a slight increase in 2022 for the first time.The ex-situ population has continued to grow,with four individuals being released back into the main stream of the Yangtze River after undergoing reintroduction training in 2023.Based on the population development lasting for over three decades,and predictions of future ecological changes,orderly establishment and scientific management of nature reserves have played a key role in and will remain an important basis for the sustaining growth of the finless porpoise population.展开更多
The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism (AFLP) technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinati...The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism (AFLP) technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinations were used to detect the genome DNA bulks of the female and male porpoises, and one sex-related AFLP marker was finally obtained. The marker can be applied to sex identification, and provides a base for further cloning of sex-related genes and analyzing of Y chromosome haplotypes of the Yangtze finless porpoise.展开更多
Under increasing anthropogenic pressure,species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations.The critically endangered Yangtze finless porpoise(Neopho...Under increasing anthropogenic pressure,species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations.The critically endangered Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),once commonly observed in the Yangtze River-Poyang Lake junction,is now rarely seen in the river-lake corridor.In this study,static passive acoustic monitoring techniques were used to detect the biosonar activities of the Yangtze finless porpoise in this unique corridor.Generalized linear models were used to examine the correlation between these activities and anthropogenic impacts from the COVID-19 pandemic lockdown and boat navigation,as well as environmental variables,including hydrological conditions and light levels.Over approximately three consecutive years of monitoring(2020–2022),porpoise biosonar was detected during 93%of logged days,indicating the key role of the corridor for finless porpoise conservation.In addition,porpoise clicks were recorded in 3.80%of minutes,while feeding correlated buzzes were detected in 1.23%of minutes,suggesting the potential existence of localized,small-scale migration.Furthermore,both anthropogenic and environmental variables were significantly correlated with the diel,lunar,monthly,seasonal,and annual variations in porpoise biosonar activities.During the pandemic lockdown period,porpoise sonar detection showed a significant increase.Furthermore,a significant negative correlation was identified between the detection of porpoise click trains and buzzes and boat traffic intensity.In addition to water level and flux,daylight and moonlight exhibited significant correlations with porpoise biosonar activities,with markedly higher detections at night and quarter moon periods.Ensuring the spatiotemporal reduction of anthropogenic activities,implementing vessel speed restrictions(e.g.,during porpoise migration and feeding),and maintaining local natural hydrological regimes are critical factors for sustaining porpoise population viability.展开更多
This report describes growth and annual reproductive cycle of female harbour porpoise (Phocoena phocoena) rescued from Japanese water in 2007. The maximum body length was 179 cm and body weight was 69.8 kg. The averag...This report describes growth and annual reproductive cycle of female harbour porpoise (Phocoena phocoena) rescued from Japanese water in 2007. The maximum body length was 179 cm and body weight was 69.8 kg. The average daily food consumption was 7.0 kg (ranging 3.7 - 9.9 kg), 11.8% of the body weight. In this report, the porpoise was kept in 17 °C water annually and the blubber thicknesses showed almost constant throughout the year (average 18 mm, range 13 - 22 mm). Therefore, we added new evidence to this hypothesis by showing that body weight and the blubber thickness do not fluctuate seasonally in fixed water temperature. Serum progesterone level of the female showed five peaks from September to November, and each cycle lasted the average of 20.5 days. Such result indicates that harbour porpoise exhibits seasonal polyestrous activity.展开更多
Harbour porpoises in the North Sea are protected under national and EU legislation, and under the regional agreement ASCOBANS, within the UN Convention on Migratory Species. As yet, no methods exist to quantify the cu...Harbour porpoises in the North Sea are protected under national and EU legislation, and under the regional agreement ASCOBANS, within the UN Convention on Migratory Species. As yet, no methods exist to quantify the cumulative impacts of direct anthropogenic mortality (e.g. by-catch) and indirect effects of human activities (e.g. contaminants) on porpoise populations. However, procedures do exist for assessing whether total anthropogenic mortality may result in failure to meet conservation objectives. While the ultimate aim is to reduce the number of such deaths to zero, ASCOBANS has an interim objective to reduce anthropogenic mortality to a level that will allow recovery of populations. Several different criteria have been proposed as limits to anthropogenic mortality that may still allow conservation objectives to be met. These criteria include simple percentages of the best population abundance estimate and more complex procedures that account for uncertainty and other information about the population. In this paper, we report new estimates of abundance for porpoises in Dutch waters, and we apply several methods to calculate maximum anthropogenic mortality limits from these estimates. We considered whether these mortality limits would meet the objective of the ASCOBANS agreement and other international obligations, and how these limits may be applied at a national level rather than the biological population level. The current simple approach of a limit of 1.7% of the best abundance estimate may not satisfy conservation objectives. We recommend the use of management procedures for setting mortality limits that take into account available data including associated uncertainties and biases, and whose performance has been extensively tested through simulation.展开更多
The Yangtze finless porpoise(YFP)is an endemic freshwater cetacean species that exclusively inhabits the middle and lower reaches of the Yangtze River basin.Since the late 1970s,the YFP has experienced a drastic popul...The Yangtze finless porpoise(YFP)is an endemic freshwater cetacean species that exclusively inhabits the middle and lower reaches of the Yangtze River basin.Since the late 1970s,the YFP has experienced a drastic population decline and was classified as critically endangered by the IUCN in 2013.To save this unique species,a range of integrated conservation measures have been implemented,including strengthening natural habitat protection(in-situ),enhancing insurance populations(ex-situ),and advancing captive breeding and research initiatives.These efforts have yielded significant progress in the conservation of the YFP.The natural population has been starting to increase after a sharp decline,and the establishment of three insurance populations has provided a solid foundation for recovery.Additionally,advancement in captive breeding and research has delivered crucial technical support for population conservation.As a flagship species of Yangtze River biodiversity and an indicator of the river’s ecosystem health,the YFP’s integrated conservation strategy not only benefits its own population but also offers valuable insights for the protection of other endangered aquatic species in the Yangtze River and other threatened small cetaceans worldwide.展开更多
Nature reserves in the Yangtze River,China,are crucial for protecting the Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)and their habitats.Despite a 10-year fishing ban along the middle and lowe...Nature reserves in the Yangtze River,China,are crucial for protecting the Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)and their habitats.Despite a 10-year fishing ban along the middle and lower reaches of the Yangtze River instated on January 2020 to alleviate pressures on the porpoise's prey,other stressors,particularly underwater noise,continue to impact these rare cetaceans,which rely heavily on vocalization for prey detection,communication and navigation.Between September 2020 and September 2021,underwater noise monitoring was carried out in the Xinluo Baiji National Nature Reserve,located in Hubei province,China,with the aim of assessing the potential impact of underwater noise pollution on the Yangtze finless porpoise.The reserve was divided into 30 sub-sections to systematically monitor underwater noise across the reserve.Passive acoustic monitoring was conducted at each site within these sub-sections during four sampling periods,and these data were subjected to comparative analysis with data collected in 2012 and 2017.The results showed that the root mean square sound pressure levels at each site ranged from 117 to 162 dB.Power spectral levels(11.2–152 kHz)exceeded the average audiogram levels for the porpoise at most sites.94.2%and 93.3%of the sites exceeded underwater acoustic thresholds known to induce a hearing threshold shift for the porpoise in terms of both the averaged cumulative unweighted sound exposure level,and cumulative weighted sound exposure level respectively.Noise levels in this section during 2020–2021 were approximately 25 and 30 dB higher compared to the levels recorded in 2012 and 2017,and likely due to increased shipping activity and the proximity of sampling sites to the shipping channel.The rise in noise levels might contribute to the observed declines in the porpoise population within this area.To mitigate these impacts,implementing noise control measures is essential,such as regulating navigation speed and limiting the number of vessels in the reserve.展开更多
Since the filling of the reservoir of the Three Gorges Project(TGP)dam in the Yangtze River in 2003,erosion downstream from the dam site has affected the finless porpoise’s habitat.In this study,a one-dimensional(1D)...Since the filling of the reservoir of the Three Gorges Project(TGP)dam in the Yangtze River in 2003,erosion downstream from the dam site has affected the finless porpoise’s habitat.In this study,a one-dimensional(1D)fluvial process mathematical model is used to calculate flow and sediment transport in the middle and lower reaches of the Yangtze River,including the finless porpoise’s habitat.By analyzing the calculation results for the water resources,suspended load,and bed materials in the finless porpoise’s habitat after the riverbed deformation,we evaluated the possible impact on this rare Yangtze River aquatic animal.The results show that,with the erosion of riverbed over the next 20 years,the water quantity comprising the habitat will decrease to half of its present amount,and the bed materials will be eroded to coarse grading,such that the reserve will become a gradually disappearing stream.Effective engineering measures should be used to decrease the erosion in the main channel,in case the overall erosion cannot be stemmed and controlled,to ensure an adequate water volume flows into the finless porpoise’s habitat.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
Lipotes usually occurs in pairs or in small loose groups. The calves are born in March-April.The Finless porpoises are usually seen in groups of five or six individuals.The blowof Lipotes lasts 0.2--0.6 sec and that o...Lipotes usually occurs in pairs or in small loose groups. The calves are born in March-April.The Finless porpoises are usually seen in groups of five or six individuals.The blowof Lipotes lasts 0.2--0.6 sec and that of Neophocaena 0.2--0.5 sec. In Lipotes,a short divewould take 10--20 sec and a long dive up to 1--2 min (average value being 31 sec). InNeophocaena a long dive would reach a maximum of 65 sec with an average of 17.5 sec.Lipotes has a pair of functional eyes. The selective secondary atrophy of a number of eyemuscles and nerves and the position of the eyes in the head correspond with the physical con-ditions of the environments so that the field of vision is directed forwards and upwards. When pursued by motor boat, both species react with a long dive and a change of direc-tion under water. With the Baiji this would occasionally cause fatal injuries by thepropeller of the ship. Such a case seems much less often with Neophocaena. The populationof Lipotes is at present very small.In the stretch of the river (between Nanjing andTaiyangzhou) under exploration, we found scarcely more than one dolphin per 4 km. Thecause for its scarcity is mostly due to accidents or wounds caused by propellers.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
Effective measures are needed to prevent the extinction of a rare Yangtze River species The finless porpoise in the Yangtze River may die out in the next
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
The genus Neophocaena includes two species,the Indo-Pacific finless porpoise(N.phocaenoides)and the Narrowridged finless porpoise(N.asiaeorientalis).The Indo-Pacific species is found in coastal waters from the Persian...The genus Neophocaena includes two species,the Indo-Pacific finless porpoise(N.phocaenoides)and the Narrowridged finless porpoise(N.asiaeorientalis).The Indo-Pacific species is found in coastal waters from the Persian Gulf through south and southeast Asia to as far north as the Taiwan Strait.The Narrow-ridged finless porpoise ranges from the Taiwan Strait to the waters of northern China,Korea,and Japan.Within N.asiaeorientalis there are two subspecies,the Yangtze finless porpoise(N.a.asiaeorientalis),found in the Yangtze River and adjoining lakes in China,and the East Asian finless porpoise(N.a.sunameri),found in coastal marine waters of China(including Hong Kong and Taiwan),Korea,and Japan.In 2019,an international workshop was held on finless porpoise research and conservation.Participants shared that,in many regions,information on distribution,abundance and population structure is lacking or inadequate.A global assessment of research is critical to provide a basis for conservation planning.Anthropogenic activities(i.e.,habitat degradation,pollution,etc.)are known threats,with fisheries bycatch the primary threat throughout the known distribution of finless porpoises.To conserve these cetaceans,research priorities include studies of abundance and distribution,habitat and ecology,fisheries-related mortality,increased public awareness,and bycatch mitigation.展开更多
Yangtze River Ecology Improves after Fishing Ban China Newsweek October 27,2025,Biodiversity has substantially improved in the main stream and tributaries of the Yangtze River where a 10-year fishing moratorium is alm...Yangtze River Ecology Improves after Fishing Ban China Newsweek October 27,2025,Biodiversity has substantially improved in the main stream and tributaries of the Yangtze River where a 10-year fishing moratorium is almost half-way through since it was introduced in 2021.Between 2021 and 2024,the number of native fish species in the catchment increased by 36 to 344.Conservation efforts have seen a rebound in the population of the Yangtze finless porpoise since 2003 to around 1,200 individuals.The only top-level predator is seen as a barometer of the waterways,ecological condition.Under tightened supervision,riverside factories and fishers were given subsidies to relocate.For five years in a row,water quality in the Yangtze mainstreams has greatly improved.Although biodiversity recovery remains ecologically and financially challenging,and rebuilding the ecological system during the next five years will be even tougher,experts believe there are still ways to achieve harmonious coexistence between people and river species.展开更多
The Yangtze River is the mother river of China.To promote the aquatic ecosystem protection of the great river,the Project of Yangtze Fisheries Resources and Environment Investigation(2017-2021)supported by the Ministr...The Yangtze River is the mother river of China.To promote the aquatic ecosystem protection of the great river,the Project of Yangtze Fisheries Resources and Environment Investigation(2017-2021)supported by the Ministry of Agriculture and Rural Affairs,P.R.China carried out by 24 institutes and universities that located in the Yangtze River basin surveys the status of(1)fish species composition and spatial distribution,(2)current fish abundance,(3)endangered fishes,(4)Yangtze finless porpoise,(5)aquatic eco-environments,(6)water-level fluctuation areas,(7)capture fisheries and recreational fisheries of the Yangtze River mainstream and 10 of its main tributaries,including Yalong River,Heng River,Min River(including Dadu River),Chishui River,Tuo River,Jialing River,Wu River,Han River,Dongting Lake and Poyang Lake.The results showed that there were 443 fish species(belonging to 163 genus,37 families,and 18 orders)before 2017,but only 323 fish species(including 15 new recorded exotic species)were recorded in the project of 2017-2021.Among them,Cyprinus carpio,Carassius auratus,Hypophthalmichthys molitrix,Pelteobagrus fulvidraco,Coilia brachygnathus,Silurus asotus,Saurogobio dabryi,Ctenopharyngodon idellus,Pelteobagrus nitidus,Hemiculter leucisculus,Siniperca chuatsi,Coreius heterodon,Culter alburnus,Parabramis pekinensis,and Aristichthys nobilis were the dominant species across the whole Yangtze River system.It is estimated that there were 886 million individuals weighing 124.8 million kg,merely equivalent to 27.3%of the resources in 1950s,30.9%of the resources in 1960s,or 58.7%of the resources in 1980s.In the new list of protected fishes that recorded in the Yangtze River system,only 15 of 29 were collected in this project of 2017-2021.Psephurus gladius has been affirmed to be Extinct by International Union for Conservation of Nature(IUCN).The wild individuals of Tenualosa reevesii and Luciobrama macrocephalus have disappeared for many years and maybe have been extinct already.Acipenser dabryanus has been affirmed to be Extinct in the Wild by IUCN.The natural propagations of A.sinensis,Myxocyprinus asiaticus and Trachidermus fasciatus have been interrupted for many years.The populations of Yangtze finless porpoise in the Yangtze River mainstream,Dongting Lake and Poyang Lake have steadily rising sizes and expanding distributions in 2017-2021.Parts of them migrate from one region to another with the seasons,which would result in the fluctuation of Yangtze finless porpoise population within some regions.The conventional indicators of water quality in the Yangtze River system were good and conformed to the water quality criteria of fishery in 2017-2021.In the last 40 years,the maximum surface water area in the Yangtze River basin extended to approximately 63,360 km2,the minimum surface water area covered approximately 26,396 km2,and the seasonal water-level fluctuation areas occupied approximately 36,964 km2.Compared with 1984-2000 period,the 2001-2020 period witnessed an overall decreasing trend in the frequency of surface water occurrence within about 25,869 km2 of aquatic areas.From 1984 to 2000 period to 2001-2020 period,permanent surface water has decreased by nearly 8,750 km2.In 2017,the fishermen were mainly 40-60 years old and their educational levels were mainly lower than junior high school.In 2017,most anglers were older than 40 and used hand rod and/or sea rod.Their average catch of each time was mainly less than 1 kg.Results suggested that the fishing ban in key waters of the Yangtze River basin is not only an ecological project of aquatic ecosystem conservation,but also a livelihood project for the fisherman to embrace industrial transformation and improve their living conditions.After the implementation of the fishing ban,the fisheries resources would gradually recover,and the Yangtze finless porpoise population size would also see a steady increase.However,the endangered species would remain threatened for a long time.The degraded waterbodies and water-level fluctuation areas would be the key restrictive factors for future aquatic ecosystem recovery in the Yangtze River basin.Since this survey was carried out before the fishing ban,the current results could provide a baseline for future evaluation of the effect of the Yangtze River fishing ban.展开更多
During the survey of potential pathogens in the Tian-e-zhou National Reserve for Lipotes vexillifer in Shishou,China,isolate SS20210504 was isolated from the diseased prey fish-Pelteobagrus fulvidraco and was identifi...During the survey of potential pathogens in the Tian-e-zhou National Reserve for Lipotes vexillifer in Shishou,China,isolate SS20210504 was isolated from the diseased prey fish-Pelteobagrus fulvidraco and was identified as Aerococcus viridans through 16S rRNA gene,morphological observation,and physiological and biochemical analysis.Artificial infection trials with fish through different methods were conducted.Results indicated that the isolate of SS2021504 caused mortality in fish with the LD50 of 1.0×106.2 CFU/mL,1.0×107.9 CFU/mL and 1.0×106.8 CFU/mL with the infection method of intraperitoneal injection,co-immersion,and scratch immersion,respectively.Challenged fish exhibited hemorrhages signs similar to naturally diseased fish.Histology analysis showed that the liver and kidney were the principal target organs of isolate SS2021504 in fish,and obvious vacuolation and karyopyknosis occurred in the above organs.To evaluate the pathogenicity of isolate SS20210504 in mice,healthy mice and immunosuppressed mice were further experimentally infected with bacteria,respectively.No death was observed either in healthy mice or in immunocompromised mice.However,the immunocompromised mice inoculated with bacteria showed obvious clinical symptoms and severe damage to multiple organs.The inflammatory signaling pathways were significantly activated with upregulated levels of Myd88,TNFα,AP-1,IL-1β,IL-6,and IFN-γgene in the spleen from the immunocompromised mice after infected with isolate SS20210504.These findings imply that isolate SS20210504 has the potential risk to YFPs and residents.Continued surveillance of A.viridans and other pathogens in the TZO reserve is suggested to prevent outbreaks in prey fish,YFPs,and residents as well.展开更多
基金The National Natural Science Foundation of China under contract Nos 42176214 and 42176170the Zhejiang Provincial Natural Science Foundation of China under contract Nos LZJWZ22E090002 and LZJWY22E090006the Key Program of the President of the Zhejiang Institute of Hydraulics and Estuaries under contract No.ZIHE21Z001.
文摘Finless porpoises(FPs)serve as flagship species and key ecological indicators for assessing environmental quality.However,FPs are challenging to survey due to their elusive behavior and lack of distinctive features.Stranding and sighting events offer essential information on species diversity,distribution patterns,and potential threats.In this study,records from 1986 to 2023 were analyzed to assess the temporal and spatial distribution patterns of FP strandings and sightings in the Qiantang River Estuary,China.Results show an increase in the number of recorded events over time.Seasonal variations were evident,with a peak in strandings and sightings occurring in late winter.The frequency of records was higher during spring and moderate tides compared to neap tides,particularly in hydrologically normal years.Rapidly receding tides and sediment accumulation appear to restrict the activity space of FPs,thereby increasing the frequency of these events.Localized conditions associated with stranding and sighting events were classified into four categories:bifurcation zones,confluence zones,separation zones,and deep channels adjacent to concave banks.Deep channels,which are optimal for shipping,also elevate the risk of FP strandings.These findings offer valuable insights for the development and design of conservation strategies tailored to the needs of FPs in estuarine environments.
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 the National Natural Science Foundation of China(42225604,31500456,31430080)the 2023 Strategic Consultation Project of the Chinese National Committee for Man and the Biosphere,the National Key Programme of Research and Development of Ministry of Science and Technology of China(2022YFF1301603)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23040403).
文摘The Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)is distributed in the main stream of the middle and lower reaches of the Yangtze River,as well as in Dongting and Poyang lakes.Currently,the most crucial conservation approach involves the establishment and management of both in-situ and ex-situ nature reserves.Since the 1990s,seven nature reserves have been established in the middle and lower reaches of the Yangtze River,covering nearly one-third of its main stream.Additionally,two nature reserves,one in the Dongting Lake and another in the Poyang Lake,have been set up;and three ex-situ nature reserves have been established in three oxbows respectively in Hunan,Hubei,and Anhui provinces.Through measures such as improving the ecological environment quality within the reserves,regulating human activities,and conducting continuous monitoring,the finless porpoise population showed a slight increase in 2022 for the first time.The ex-situ population has continued to grow,with four individuals being released back into the main stream of the Yangtze River after undergoing reintroduction training in 2023.Based on the population development lasting for over three decades,and predictions of future ecological changes,orderly establishment and scientific management of nature reserves have played a key role in and will remain an important basis for the sustaining growth of the finless porpoise population.
文摘The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism (AFLP) technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinations were used to detect the genome DNA bulks of the female and male porpoises, and one sex-related AFLP marker was finally obtained. The marker can be applied to sex identification, and provides a base for further cloning of sex-related genes and analyzing of Y chromosome haplotypes of the Yangtze finless porpoise.
基金supported by Science and Technology Service Network Initiative Program of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (41806197)the Exploratory Program of the Natural Science Foundation of Zhejiang Province (ZX2023000154)。
文摘Under increasing anthropogenic pressure,species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations.The critically endangered Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),once commonly observed in the Yangtze River-Poyang Lake junction,is now rarely seen in the river-lake corridor.In this study,static passive acoustic monitoring techniques were used to detect the biosonar activities of the Yangtze finless porpoise in this unique corridor.Generalized linear models were used to examine the correlation between these activities and anthropogenic impacts from the COVID-19 pandemic lockdown and boat navigation,as well as environmental variables,including hydrological conditions and light levels.Over approximately three consecutive years of monitoring(2020–2022),porpoise biosonar was detected during 93%of logged days,indicating the key role of the corridor for finless porpoise conservation.In addition,porpoise clicks were recorded in 3.80%of minutes,while feeding correlated buzzes were detected in 1.23%of minutes,suggesting the potential existence of localized,small-scale migration.Furthermore,both anthropogenic and environmental variables were significantly correlated with the diel,lunar,monthly,seasonal,and annual variations in porpoise biosonar activities.During the pandemic lockdown period,porpoise sonar detection showed a significant increase.Furthermore,a significant negative correlation was identified between the detection of porpoise click trains and buzzes and boat traffic intensity.In addition to water level and flux,daylight and moonlight exhibited significant correlations with porpoise biosonar activities,with markedly higher detections at night and quarter moon periods.Ensuring the spatiotemporal reduction of anthropogenic activities,implementing vessel speed restrictions(e.g.,during porpoise migration and feeding),and maintaining local natural hydrological regimes are critical factors for sustaining porpoise population viability.
文摘This report describes growth and annual reproductive cycle of female harbour porpoise (Phocoena phocoena) rescued from Japanese water in 2007. The maximum body length was 179 cm and body weight was 69.8 kg. The average daily food consumption was 7.0 kg (ranging 3.7 - 9.9 kg), 11.8% of the body weight. In this report, the porpoise was kept in 17 °C water annually and the blubber thicknesses showed almost constant throughout the year (average 18 mm, range 13 - 22 mm). Therefore, we added new evidence to this hypothesis by showing that body weight and the blubber thickness do not fluctuate seasonally in fixed water temperature. Serum progesterone level of the female showed five peaks from September to November, and each cycle lasted the average of 20.5 days. Such result indicates that harbour porpoise exhibits seasonal polyestrous activity.
文摘Harbour porpoises in the North Sea are protected under national and EU legislation, and under the regional agreement ASCOBANS, within the UN Convention on Migratory Species. As yet, no methods exist to quantify the cumulative impacts of direct anthropogenic mortality (e.g. by-catch) and indirect effects of human activities (e.g. contaminants) on porpoise populations. However, procedures do exist for assessing whether total anthropogenic mortality may result in failure to meet conservation objectives. While the ultimate aim is to reduce the number of such deaths to zero, ASCOBANS has an interim objective to reduce anthropogenic mortality to a level that will allow recovery of populations. Several different criteria have been proposed as limits to anthropogenic mortality that may still allow conservation objectives to be met. These criteria include simple percentages of the best population abundance estimate and more complex procedures that account for uncertainty and other information about the population. In this paper, we report new estimates of abundance for porpoises in Dutch waters, and we apply several methods to calculate maximum anthropogenic mortality limits from these estimates. We considered whether these mortality limits would meet the objective of the ASCOBANS agreement and other international obligations, and how these limits may be applied at a national level rather than the biological population level. The current simple approach of a limit of 1.7% of the best abundance estimate may not satisfy conservation objectives. We recommend the use of management procedures for setting mortality limits that take into account available data including associated uncertainties and biases, and whose performance has been extensively tested through simulation.
文摘The Yangtze finless porpoise(YFP)is an endemic freshwater cetacean species that exclusively inhabits the middle and lower reaches of the Yangtze River basin.Since the late 1970s,the YFP has experienced a drastic population decline and was classified as critically endangered by the IUCN in 2013.To save this unique species,a range of integrated conservation measures have been implemented,including strengthening natural habitat protection(in-situ),enhancing insurance populations(ex-situ),and advancing captive breeding and research initiatives.These efforts have yielded significant progress in the conservation of the YFP.The natural population has been starting to increase after a sharp decline,and the establishment of three insurance populations has provided a solid foundation for recovery.Additionally,advancement in captive breeding and research has delivered crucial technical support for population conservation.As a flagship species of Yangtze River biodiversity and an indicator of the river’s ecosystem health,the YFP’s integrated conservation strategy not only benefits its own population but also offers valuable insights for the protection of other endangered aquatic species in the Yangtze River and other threatened small cetaceans worldwide.
文摘Nature reserves in the Yangtze River,China,are crucial for protecting the Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)and their habitats.Despite a 10-year fishing ban along the middle and lower reaches of the Yangtze River instated on January 2020 to alleviate pressures on the porpoise's prey,other stressors,particularly underwater noise,continue to impact these rare cetaceans,which rely heavily on vocalization for prey detection,communication and navigation.Between September 2020 and September 2021,underwater noise monitoring was carried out in the Xinluo Baiji National Nature Reserve,located in Hubei province,China,with the aim of assessing the potential impact of underwater noise pollution on the Yangtze finless porpoise.The reserve was divided into 30 sub-sections to systematically monitor underwater noise across the reserve.Passive acoustic monitoring was conducted at each site within these sub-sections during four sampling periods,and these data were subjected to comparative analysis with data collected in 2012 and 2017.The results showed that the root mean square sound pressure levels at each site ranged from 117 to 162 dB.Power spectral levels(11.2–152 kHz)exceeded the average audiogram levels for the porpoise at most sites.94.2%and 93.3%of the sites exceeded underwater acoustic thresholds known to induce a hearing threshold shift for the porpoise in terms of both the averaged cumulative unweighted sound exposure level,and cumulative weighted sound exposure level respectively.Noise levels in this section during 2020–2021 were approximately 25 and 30 dB higher compared to the levels recorded in 2012 and 2017,and likely due to increased shipping activity and the proximity of sampling sites to the shipping channel.The rise in noise levels might contribute to the observed declines in the porpoise population within this area.To mitigate these impacts,implementing noise control measures is essential,such as regulating navigation speed and limiting the number of vessels in the reserve.
基金supported by the National Natural Science Foundation of China(Grant No.51139003)
文摘Since the filling of the reservoir of the Three Gorges Project(TGP)dam in the Yangtze River in 2003,erosion downstream from the dam site has affected the finless porpoise’s habitat.In this study,a one-dimensional(1D)fluvial process mathematical model is used to calculate flow and sediment transport in the middle and lower reaches of the Yangtze River,including the finless porpoise’s habitat.By analyzing the calculation results for the water resources,suspended load,and bed materials in the finless porpoise’s habitat after the riverbed deformation,we evaluated the possible impact on this rare Yangtze River aquatic animal.The results show that,with the erosion of riverbed over the next 20 years,the water quantity comprising the habitat will decrease to half of its present amount,and the bed materials will be eroded to coarse grading,such that the reserve will become a gradually disappearing stream.Effective engineering measures should be used to decrease the erosion in the main channel,in case the overall erosion cannot be stemmed and controlled,to ensure an adequate water volume flows into the finless porpoise’s habitat.
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.
文摘Lipotes usually occurs in pairs or in small loose groups. The calves are born in March-April.The Finless porpoises are usually seen in groups of five or six individuals.The blowof Lipotes lasts 0.2--0.6 sec and that of Neophocaena 0.2--0.5 sec. In Lipotes,a short divewould take 10--20 sec and a long dive up to 1--2 min (average value being 31 sec). InNeophocaena a long dive would reach a maximum of 65 sec with an average of 17.5 sec.Lipotes has a pair of functional eyes. The selective secondary atrophy of a number of eyemuscles and nerves and the position of the eyes in the head correspond with the physical con-ditions of the environments so that the field of vision is directed forwards and upwards. When pursued by motor boat, both species react with a long dive and a change of direc-tion under water. With the Baiji this would occasionally cause fatal injuries by thepropeller of the ship. Such a case seems much less often with Neophocaena. The populationof Lipotes is at present very small.In the stretch of the river (between Nanjing andTaiyangzhou) under exploration, we found scarcely more than one dolphin per 4 km. Thecause for its scarcity is mostly due to accidents or wounds caused by propellers.
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.
文摘Effective measures are needed to prevent the extinction of a rare Yangtze River species The finless porpoise in the Yangtze River may die out in the next
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.
基金supported by the National Science Foundation Research Traineeship[award number 1633336]。
文摘The genus Neophocaena includes two species,the Indo-Pacific finless porpoise(N.phocaenoides)and the Narrowridged finless porpoise(N.asiaeorientalis).The Indo-Pacific species is found in coastal waters from the Persian Gulf through south and southeast Asia to as far north as the Taiwan Strait.The Narrow-ridged finless porpoise ranges from the Taiwan Strait to the waters of northern China,Korea,and Japan.Within N.asiaeorientalis there are two subspecies,the Yangtze finless porpoise(N.a.asiaeorientalis),found in the Yangtze River and adjoining lakes in China,and the East Asian finless porpoise(N.a.sunameri),found in coastal marine waters of China(including Hong Kong and Taiwan),Korea,and Japan.In 2019,an international workshop was held on finless porpoise research and conservation.Participants shared that,in many regions,information on distribution,abundance and population structure is lacking or inadequate.A global assessment of research is critical to provide a basis for conservation planning.Anthropogenic activities(i.e.,habitat degradation,pollution,etc.)are known threats,with fisheries bycatch the primary threat throughout the known distribution of finless porpoises.To conserve these cetaceans,research priorities include studies of abundance and distribution,habitat and ecology,fisheries-related mortality,increased public awareness,and bycatch mitigation.
文摘Yangtze River Ecology Improves after Fishing Ban China Newsweek October 27,2025,Biodiversity has substantially improved in the main stream and tributaries of the Yangtze River where a 10-year fishing moratorium is almost half-way through since it was introduced in 2021.Between 2021 and 2024,the number of native fish species in the catchment increased by 36 to 344.Conservation efforts have seen a rebound in the population of the Yangtze finless porpoise since 2003 to around 1,200 individuals.The only top-level predator is seen as a barometer of the waterways,ecological condition.Under tightened supervision,riverside factories and fishers were given subsidies to relocate.For five years in a row,water quality in the Yangtze mainstreams has greatly improved.Although biodiversity recovery remains ecologically and financially challenging,and rebuilding the ecological system during the next five years will be even tougher,experts believe there are still ways to achieve harmonious coexistence between people and river species.
文摘The Yangtze River is the mother river of China.To promote the aquatic ecosystem protection of the great river,the Project of Yangtze Fisheries Resources and Environment Investigation(2017-2021)supported by the Ministry of Agriculture and Rural Affairs,P.R.China carried out by 24 institutes and universities that located in the Yangtze River basin surveys the status of(1)fish species composition and spatial distribution,(2)current fish abundance,(3)endangered fishes,(4)Yangtze finless porpoise,(5)aquatic eco-environments,(6)water-level fluctuation areas,(7)capture fisheries and recreational fisheries of the Yangtze River mainstream and 10 of its main tributaries,including Yalong River,Heng River,Min River(including Dadu River),Chishui River,Tuo River,Jialing River,Wu River,Han River,Dongting Lake and Poyang Lake.The results showed that there were 443 fish species(belonging to 163 genus,37 families,and 18 orders)before 2017,but only 323 fish species(including 15 new recorded exotic species)were recorded in the project of 2017-2021.Among them,Cyprinus carpio,Carassius auratus,Hypophthalmichthys molitrix,Pelteobagrus fulvidraco,Coilia brachygnathus,Silurus asotus,Saurogobio dabryi,Ctenopharyngodon idellus,Pelteobagrus nitidus,Hemiculter leucisculus,Siniperca chuatsi,Coreius heterodon,Culter alburnus,Parabramis pekinensis,and Aristichthys nobilis were the dominant species across the whole Yangtze River system.It is estimated that there were 886 million individuals weighing 124.8 million kg,merely equivalent to 27.3%of the resources in 1950s,30.9%of the resources in 1960s,or 58.7%of the resources in 1980s.In the new list of protected fishes that recorded in the Yangtze River system,only 15 of 29 were collected in this project of 2017-2021.Psephurus gladius has been affirmed to be Extinct by International Union for Conservation of Nature(IUCN).The wild individuals of Tenualosa reevesii and Luciobrama macrocephalus have disappeared for many years and maybe have been extinct already.Acipenser dabryanus has been affirmed to be Extinct in the Wild by IUCN.The natural propagations of A.sinensis,Myxocyprinus asiaticus and Trachidermus fasciatus have been interrupted for many years.The populations of Yangtze finless porpoise in the Yangtze River mainstream,Dongting Lake and Poyang Lake have steadily rising sizes and expanding distributions in 2017-2021.Parts of them migrate from one region to another with the seasons,which would result in the fluctuation of Yangtze finless porpoise population within some regions.The conventional indicators of water quality in the Yangtze River system were good and conformed to the water quality criteria of fishery in 2017-2021.In the last 40 years,the maximum surface water area in the Yangtze River basin extended to approximately 63,360 km2,the minimum surface water area covered approximately 26,396 km2,and the seasonal water-level fluctuation areas occupied approximately 36,964 km2.Compared with 1984-2000 period,the 2001-2020 period witnessed an overall decreasing trend in the frequency of surface water occurrence within about 25,869 km2 of aquatic areas.From 1984 to 2000 period to 2001-2020 period,permanent surface water has decreased by nearly 8,750 km2.In 2017,the fishermen were mainly 40-60 years old and their educational levels were mainly lower than junior high school.In 2017,most anglers were older than 40 and used hand rod and/or sea rod.Their average catch of each time was mainly less than 1 kg.Results suggested that the fishing ban in key waters of the Yangtze River basin is not only an ecological project of aquatic ecosystem conservation,but also a livelihood project for the fisherman to embrace industrial transformation and improve their living conditions.After the implementation of the fishing ban,the fisheries resources would gradually recover,and the Yangtze finless porpoise population size would also see a steady increase.However,the endangered species would remain threatened for a long time.The degraded waterbodies and water-level fluctuation areas would be the key restrictive factors for future aquatic ecosystem recovery in the Yangtze River basin.Since this survey was carried out before the fishing ban,the current results could provide a baseline for future evaluation of the effect of the Yangtze River fishing ban.
文摘During the survey of potential pathogens in the Tian-e-zhou National Reserve for Lipotes vexillifer in Shishou,China,isolate SS20210504 was isolated from the diseased prey fish-Pelteobagrus fulvidraco and was identified as Aerococcus viridans through 16S rRNA gene,morphological observation,and physiological and biochemical analysis.Artificial infection trials with fish through different methods were conducted.Results indicated that the isolate of SS2021504 caused mortality in fish with the LD50 of 1.0×106.2 CFU/mL,1.0×107.9 CFU/mL and 1.0×106.8 CFU/mL with the infection method of intraperitoneal injection,co-immersion,and scratch immersion,respectively.Challenged fish exhibited hemorrhages signs similar to naturally diseased fish.Histology analysis showed that the liver and kidney were the principal target organs of isolate SS2021504 in fish,and obvious vacuolation and karyopyknosis occurred in the above organs.To evaluate the pathogenicity of isolate SS20210504 in mice,healthy mice and immunosuppressed mice were further experimentally infected with bacteria,respectively.No death was observed either in healthy mice or in immunocompromised mice.However,the immunocompromised mice inoculated with bacteria showed obvious clinical symptoms and severe damage to multiple organs.The inflammatory signaling pathways were significantly activated with upregulated levels of Myd88,TNFα,AP-1,IL-1β,IL-6,and IFN-γgene in the spleen from the immunocompromised mice after infected with isolate SS20210504.These findings imply that isolate SS20210504 has the potential risk to YFPs and residents.Continued surveillance of A.viridans and other pathogens in the TZO reserve is suggested to prevent outbreaks in prey fish,YFPs,and residents as well.
