Role of air sinuses in sound reception of the Yangtze finless porpoise: A numerical study.

Although air sinuses are prevalent in odontocetes and are an integral component of their sound reception system, the acoustic function of these air-filled structures remains largely unknown. To address this, we developed a numerical model using computed tomography data from a Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) to investigate the role of the air sinuses in sound reception. By comparing sound reception characteristics between model cases with and without the air sinuses, we found that the air sinuses improved sound reception directivity.

Effect of calf separation on gut microbiome and fecal metabolome of mother in the captive Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis).

Social separation, or the absence of social support, can cause physical and psychological health issues. Social separation is crucial for the welfare of the Yangtze finless porpoise (YFP) in captivity because they face many challenges like frequent social separation, noise from visitors, and animal replacement, which can cause psychological and physiological stress. This research is aimed at assessing the potential negative impacts of social separation on the gut microbiome and metabolome of captive YFP, focusing on the potential imbalances caused by mother-calf separation.

Physiological function of gut microbiota and metabolome on successful pregnancy and lactation in the captive Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)†.

Gestation period in captive Yangtze finless porpoise (YFP) is a well-coordinated and dynamic process, involving both systemic and local alterations. The gut microbiota and its connection to fecal metabolites are crucial in supporting fetal development and ensuring maternal health during reproductive stages. This study evaluates changes in the gut microbiota and their correlation with fecal metabolites in captive YFPs during different reproductive stages.

Spatial distribution, trophic magnification, and risk assessment of per- and polyfluoroalkyl substances in Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis): Risks of emerging alternatives.

The Yangtze finless porpoise (YFP, Neophocaena asiaeorientalis asiaeorientalis) is the only freshwater cetacean found in China. However, per- and polyfluoroalkyl substances (PFASs) risks in YFPs remain unclear. In this study, legacy PFASs, their precursors and alternatives, were determined in YFP muscles (n = 32), liver (n = 29), kidney (n = 24), skin (n = 5), and blubbers (n = 25) collected from Poyang Lake (PL) and Yangtze River (YR) between 2017 and 2023.

Temporal and spatial biosonar activity of the recently established uppermost Yangtze finless porpoise population downstream of the Gezhouba Dam: Correlation with hydropower cascade development, shipping, hydrological regime, and light intensity.

Numerous dams disrupt freshwater animals. The uppermost population of the critically endangered Yangtze finless porpoise has been newly formed below the Gezhouba Dam, however, information regarding the local porpoise is scarce. Passive acoustic monitoring was used to detect the behaviors of porpoises below the Gezhouba Dam.

Increased Yangtze finless porpoise presence in urban Wuhan waters of the Yangtze River during fishing closures.

Wuhan, a highly urbanized and rapidly growing region within China's Yangtze Economic Zone, has historically been identified as a gap area for the critically endangered Yangtze finless porpoise () based on daytime visual surveys. However, there has been a noticeable increase in porpoise sightings since 2020. This study employed passive acoustic monitoring to investigate porpoise distribution in Wuhan between 2020 and 2022.

Biological characteristics of pregnancy in captive Yangtze finless porpoises revealed by urinary metabolomics†.

The Yangtze finless porpoises (Neophocaena asiaeorientalis a.) are an endemic and critically endangered species in China. Intensive captive breeding is essential for understanding the biology of critically endangered species, especially their pregnancy characteristics, knowledge of which is crucial for effective breeding management.

Anthropogenic activity, hydrological regime, and light level jointly influence temporal patterns in biosonar activity of the Yangtze finless porpoise at the junction of the Yangtze River and Poyang Lake, China.

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 ( ), 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.

Sound Reception in the Yangtze Finless Porpoise and Its Extension to a Biomimetic Receptor.

Sound reception was investigated in the Yangtze finless porpoise () at its most sensitive frequency. The computed tomography scanning, sound speed, and density results were used to develop a three-dimensional numerical model of the porpoise sound-reception system. The acoustic fields showed that sounds can reach the ear complexes from various pathways, with distinct receptivity peaks on the forward, left, and right sides.

Ecological impacts of unsustainable sand mining: urgent lessons learned from a critically endangered freshwater cetacean.

Sand mining, which has tripled in the last two decades, is an emerging concern for global biodiversity. However, the paucity of sand mining data worldwide prevents understanding the extent of sand mining impacts and how it affects wildlife populations and ecosystems, which is critical for timely mitigation and conservation actions. Integrating remote sensing and field surveys over 14 years, we investigated mining impacts on the critically endangered Yangtze finless porpoise () in Dongting Lake, China.

Accumulation and risk prioritization of psychoactive substances in the critically endangered Yangtze finless porpoise.

Psychoactive substances have been identified as a kind of emerging contaminants in aquatic environment and pose potential adverse effects on aquatic animals. Yangtze finless porpoise, a critically endangered species in China, is also facing the threat of psychoactive substances. In this study, the accumulation characteristics and risk prioritization of psychoactive substances were investigated in Yangtze finless porpoise collected from Poyang Lake (PYL) and Tian-E-Zhou Oxbow (TZO) in Yangtze River basin.

Biogeographic patterns of potential pathogenic bacteria in the middle and lower reaches of the Yangtze River as well as its two adjoining lakes, China.

Understanding the distribution patterns and shaping factors of bacterial pathogens in aquatic ecosystems, especially in natural waters, are critical to the control of pathogen transmission. In this study, using gene amplicon sequencing, we explored the composition and biogeographic dynamics of potential bacterial pathogens in the middle and lower reaches of the Yangtze River, as well as its two vast adjoining lakes (Dongting Lake and Poyang Lake). The pathogen community belonged to 12 potential pathogenic groups, with "intracellular parasites," "animal parasites or symbionts" and "human pathogens all" occupying 97.

Circulating concentrations of thyroid hormones and cortisol in wild and semi-natural Yangtze finless porpoise ().

Our understanding about how environmental and biological variables may influence circulating thyroid and adrenal hormones in free-ranging cetaceans is limited. As such, we used liquid chromatography-mass spectrometry to determine concentrations of circulating cortisol and thyroid hormones (THs; tT3, tT4) in 132 Yangtze finless porpoises (YFPs) located in Poyang Lake, (PL,  = 92) and Tian-E-Zhou Oxbow reserve (TZO,  = 40). For overall hormone comparisons, animals were partitioned by age [juvenile and adult (male and non-pregnant, non-lactating female)], sex, season (winter or spring) and geographical location.

Auditory evoked potential in stranded melon-headed whales (Peponocephala electra): With severe hearing loss and possibly caused by anthropogenic noise pollution.

Highly concentrated live mass stranding events of dolphins and whales happened in the eastern coast of China between June and October 2021. The current study adopted the non-invasive auditory evoked-potential technique to investigate the hearing threshold of a stranded melon headed whale (Peponocephala electra) at a frequency range of between 9.5 and 181 kHz.

Blubber fatty acid compositions in different geographic populations of finless porpoise in Chinese waters: implications for thermal adaptation.

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.

Riverside underwater noise pollution threaten porpoises and fish along the middle and lower reaches of the Yangtze River, China.

The Yangtze River exhibits a high biodiversity and plays an important role in global biodiversity conservation. As the world's busiest inland river in regard to shipping, little attention has been paid to underwater noise pollution. In 2017, the underwater noise level in 25 riverside locations along the middle and lower reaches of the Yangtze River mainly at night time were investigated by using passive acoustic monitoring method.

Seasonal Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) movements in the Poyang Lake, China: Implications on flexible management for aquatic animals in fluctuating freshwater ecosystems.

Identifying seasonal high-use habitats and migration corridors is the basis for migratory species conservation. Previous studies have focused on Marine Protected Areas, while freshwater ecosystems, often accompanied by severe hydrological fluctuations, suggest new perspectives for flexible management. Poyang Lake is an essential habitat for the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis, YFP), supporting almost half of their natural population.

Whistle signal variations among three Indo-Pacific humpback dolphin populations in the South China Sea: a combined effect of the Qiongzhou Strait's geographical barrier function and local ambient noise?

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.

Thresholds of population persistence for the Yangtze finless porpoise: implications for conservation managements.

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis), a critically endangered species, is the only cetacean species in the Yangtze River following the functional extinction of baiji (Lipotes vexillifer). To inform conservation actions, two important questions need to be addressed: what is the threshold value of survival rate, and what is the threshold value of population size? We calculate the instantaneous rate of population increase ( ) for the Yangtze finless porpoise for various combinations of the calf and the non-calf survival rates. We also test the probability of extinction for different minimum carrying capacities for 100 and 500 years using a stable population model.

Community-based population monitoring for large baleen whales: the case study of Bryde's whale in Beibu Gulf of China.

Citizen science is a popular method for the long-term monitoring of the distribution of wild animals. The application of these methods in different species and environments still poses challenges, especially for aquatic animals. In this study, we investigated the distribution of the Bryde's whale (Balaenoptera edeni) in the Beibu Gulf of China by using scientific boat-based surveys and citizen science approaches using 2 different methods of data collection.

Evoked-potential audiogram variability in a group of wild Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).

Hearing is considered the primary sensory modality of cetaceans and enables their vital life functions. Information on the hearing sensitivity variability within a species obtained in a biologically relevant wild context is fundamental to evaluating potential noise impact and population-relevant management. Here, non-invasive auditory evoked-potential methods were adopted to describe the audiograms (11.

Underwater noise pollution in China's Yangtze River critically endangers Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).

Underwater sound plays an important role in some critical life functions of many aquatic animals. Underwater noise pollution has received relatively more attention in ocean systems. However, little attention has been paid to freshwater systems, such as the Yangtze River which is the habitat of critically endangered Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).