Trace elements accumulation in the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) – A threat to the endangered freshwater cetacean

Xiong, Xiong; Qian, Zhengyi; Mei, Zhigang; Wu, Jianhong; Hao, Yiming; Wang, Kexiong; Wu, Chenxi; Wang, Ding

doi:10.1016/j.scitotenv.2019.06.031

Cited by 18 publications

(7 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Multiple mechanisms could reduce porpoise reproductive success and/or survivorship, hindering identification of cause(s). High concentrations of pollutants that affect cetacean reproduction and calf survival (heavy metals, persistent organic pollutants) have been found in Yangtze finless porpoise carcasses (Dong et al, 2006;Yang et al, 2008;Xiong et al, 2019), Yangtze fish (Xian et al, 2008), and the Yangtze River (Müller et al, 2008), with highest mercury concentrations and polychlorinated biphenyl hazard quotients found in porpoise calves (Dong et al, 2006;Yang et al, 2008). Although few data exist on specific Yangtze fish decreases (including porpoise prey species), fish stocks have declined substantially through habitat loss/degradation and damming (Ye et al, 2013), and decreased prey availability is associated with reduced reproductive success in several cetaceans (Mann, 2000;Ford et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The relative impact of different potential porpoise threats has been the subject of limited research. Previous studies consist largely of investigating local-scale porpoise distributions in relation to available resources (Kimura et al, 2012;Wang et al, 2014), and opportunistically-observed porpoise deaths associated with specific threats including fisheries bycatch, propeller collisions, and pollutants (Zhou and Wang, 1994;Wang et al, 2000Wang et al, , 2015Dong et al, 2006;Yang et al, 2008;Turvey et al, 2013;Xiong et al, 2019). Two population viability analyses have been conducted to model future decline (Zhang and Wang, 1999;Huang et al, 2017); however, neither attempted to quantify sustainable levels of offtake (the number of individuals removed from the environment through hunting, harvesting, or other killing by humans; cf.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Precautionary Principle or Evidence-Based Conservation? Assessing the Information Content of Threat Data for the Yangtze Finless Porpoise

et al. 2022

Self Cite

View full text Add to dashboard Cite

Conservation management requires evidence, but robust data on key parameters such as threats are often unavailable. Conservation-relevant insights might be available within datasets collected for other reasons, making it important to determine the information content of available data for threatened species and identify remaining data-gaps before investing time and resources in novel data collection. The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) has declined severely across the middle-lower Yangtze, but multiple threats exist in this system and the relative impact of different anthropogenic activities is unclear, preventing identification of appropriate mitigation strategies. Several datasets containing information on porpoises or potential threats are available from past boat-based and fishing community surveys, which might provide novel insights into causes of porpoise mortality and decline. We employed multiple analytical approaches to investigate spatial relationships between live and dead porpoises and different threats, reproductive trends over time, and sustainable offtake levels, to assess whether evidence-based conservation is feasible under current data availability. Our combined analyses provide new evidence that mortality is spatially associated with increased cargo traffic; observed mortality levels (probably a substantial underestimate of true levels) are unsustainable; and population recruitment is decreasing, although multiple factors could be responsible (pollutants, declining fish stocks, anthropogenic noise, reduced genetic diversity). Available data show little correlation between patterns of mortality and fishing activity even when analyzed across multiple spatial scales; however, interview data can be affected by multiple biases that potentially complicate attempts to reconstruct levels of bycatch, and new data are required to understand dynamics and sustainability of porpoise-fisheries interactions. This critical assessment of existing data thus suggests that in situ porpoise conservation management must target multiple co-occurring threats. Even limited available datasets can provide new insights for understanding declines, and we demonstrate the importance of an integrative approach for investigating complex conservation problems and maximizing evidence in conservation planning for poorly known taxa.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Precautionary Principle or Evidence-Based Conservation? Assessing the Information Content of Threat Data for the Yangtze Finless Porpoise

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…Mercury pollution can come from natural deposits, mining, and other industrial processes (7 publications, 35% of the co-authors). Tissue samples from Yangtze finless porpoises have shown that mercury accumulation in the liver was correlated with body size and was passed to new-born calves (Dong et al 2006, Xiong et al 2019. Mercury concentrations were also correlated with high concentrations of selenium, which seems to be produced by the animal (Xiong et al 2019), implying a protective function as has been observed in coastal dolphins (Turnbull & Cowan 1998, Kehrig et al 2016.…”

Section: Heavy Metalsmentioning

confidence: 96%

Challenges and priorities for river cetacean conservation

Campbell

Alfaro‐Shigueto

Aliaga-Rossel

et al. 2022

Endang. Species. Res.

View full text Add to dashboard Cite

River cetaceans are particularly vulnerable to anthropogenic impacts due to their constrained ranges in freshwater systems of China, South Asia, and South America. We undertook an exhaustive review of 280 peer-reviewed papers and grey literature reports (1998-2020) to examine the current status of knowledge regarding these cetaceans and their conservation. We aimed to better understand the scale of threats they face, and to identify and propose priority future efforts to better conserve these species. We found that the species have been studied with varying frequency and that most of the research on threats has focused on habitat degradation and fragmentation (43%, mainly driven by dams and extractive activities such as sand mining and deforestation), and fishery interactions (39%, in the form of bycatch and direct take). These threats occur across all species, but more information is needed, primarily on quantifying the population impacts as a basis for designing mitigation measures. Other threats identified include pollution, vessel collisions, traditional use, and poorly managed tourism. Emerging methods such as environmental DNA and unmanned aerial vehicles are described for studying these species. Promising conservation interventions include cetacean-specific protected areas, natural ex situ protection, community-led conservation, and education programmes. However, transnational political will is required for a step change towards broad-scale protection in freshwater environments. In addition, we propose increasing capacity building, developing management plans, working closely with fishing communities, enhancing public awareness, expanding regional collaborations, and diversifying funding.

show abstract

“…The large quantity of prey consumed, and the long lifespan of dolphins further enhances their capacity to accumulate metals (Aguilar et al, 1999;Bowles, 1999). Like other cetaceans, several toxic pollutants have been reported in the various tissues of YFPs (Xiong et al, 2019). Though not specifically studied in detailed in the IRD, the bioaccumulation of metals could cause higher mortality, morbidity as well as could negatively compromise reproduction, putting the population health and growth atrisk (Aguilar et al, 1999;Murphy et al, 2015).…”

Section: Industrial Pollutionmentioning

confidence: 99%

Deteriorating Habitats and Conservation Strategies to Repopulate the Endangered Indus River Dolphin (Platanista gangetica minor); a Lesson Learned From the Conservation Practices of the Yangtze Finless Porpoise (Neophocaena asiaeorientalis)

et al. 2021

Self Cite

View full text Add to dashboard Cite

The Indus River dolphin (IRD; Platanista gangetica minor) is an endangered and blind freshwater cetacean, endemic to the Indus River system of Pakistan and India. This review article provides detailed information about the major challenges IRDs are facing, and their possible consequences on the population dynamics of the IRD. Furthermore, we have suggested future conservation strategies for the IRD based on the lesson learned from the conservation of the Yangtze finless porpoise (YFP; Neophocaena asiaeorientalis), a Critically Endangered freshwater cetacean. The major challenges for IRDs are habitat degradation, habitat fragmentation, and several types of industrial and agricultural pollutants. Worsening climatic changes, illegal fishing, and overfishing are additional threats. The construction of several barrages has fragmented the population into several short segments, some of which are too small for the IRDs to survive. In some segments, the population status of the IRD is unknown. In the remaining populations, genetic inbreeding, water shortage, canal entrapment, and altered ecological environment are potent negative factors for the survival of the IRD. Conservation strategies including fishing bans, translocation, and future research (tagging, periodic health assessments, necropsy and virtopsy, understanding the reproductive biology, and genomics) are possible recommendations. Very serious conservation efforts are needed to save the IRD from decline keeping in view the water shortage, pollution, lack of health assessment studies, and habitat degradation and fragmentation.

show abstract

Trace elements accumulation in the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) – A threat to the endangered freshwater cetacean

Cited by 18 publications

References 54 publications

Precautionary Principle or Evidence-Based Conservation? Assessing the Information Content of Threat Data for the Yangtze Finless Porpoise

Precautionary Principle or Evidence-Based Conservation? Assessing the Information Content of Threat Data for the Yangtze Finless Porpoise

Challenges and priorities for river cetacean conservation

Deteriorating Habitats and Conservation Strategies to Repopulate the Endangered Indus River Dolphin (Platanista gangetica minor); a Lesson Learned From the Conservation Practices of the Yangtze Finless Porpoise (Neophocaena asiaeorientalis)

Contact Info

Product

Resources

About