Mark-Recapture Analysis of the Critically Endangered Eastern Taiwan Strait Population of Indo-Pacific Humpback Dolphins (<i>Sousa Chinensis</i>): Implications for Conservation

Wang, John Y.; Yang, Shih Chu; Fruet, Pedro F.; Daura‐Jorge, Fábio G.; Secchi, Eduardo R.

doi:10.5343/bms.2010.1097

Cited by 46 publications

(64 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, mark-recapture analyses of photo-identification data generated more precise abundance estimates, with a maximum annual point estimate of only 74 ind. (Wang et al 2012), suggesting that the population is smaller than previously indicated.…”

Section: Introductionmentioning

confidence: 56%

“…However, such information is still unavailable for many cetacean species and populations because mark-recapture analyses require long-term data collection, tend to be re source-and time-intensive, and the behaviour of some species is not conducive to the tracking of individuals over several years. Fortunately, the ETS population of humpback dolphins possesses characteristics that make it an ideal population for mark-recapture ana lyses (see Wang et al 2012). The recent precise abundance and first survivorship estimates presented by Wang et al (2012) provided information allowing a more reliable examination of the extinction risks of this population under various scenarios.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Viability of the Critically Endangered eastern Taiwan Strait population of Indo-Pacific humpback dolphins Sousa chinensis

Araújo¹,

Wang²,

Hung³

et al. 2014

Endang. Species. Res.

View full text Add to dashboard Cite

The population of humpback dolphins Sousa chinensis that resides in the eastern Taiwan Strait (ETS) is geographically and genetically isolated from populations inhabiting the coastal waters of mainland China and appears to be facing unsustainable levels of human threats. Using VORTEX 9.99b, we modeled the viability of this Critically Endangered population under the present conditions as well as under realistic additional threat scenarios. We examined 6 different levels of bycatch mortality, 3 scenarios of habitat loss/degradation, and scenarios in which these threats were experienced together. Under the baseline (present) scenario, the population exhibited a decreasing growth rate and was predicted to be smaller than the initial population size in more than 76% of all model runs. In all scenarios with additional threats, the proportion of model runs in which population size was smaller than the initial size varied from 77.1 to 92.6%. Over the short term, fisheries-related mortality appears to have a more obvious impact on the population's trajectory than habitat loss/degradation. Even minimal increases in mortality from the current baseline levels will increase the probability of extinction of this population. Due to the fragile situation of ETS humpback dolphins, mitigation actions to reduce the current threats to this population are needed immediately.

show abstract

Section: Introductionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Viability of the Critically Endangered eastern Taiwan Strait population of Indo-Pacific humpback dolphins Sousa chinensis

Araújo¹,

Wang²,

Hung³

et al. 2014

Endang. Species. Res.

View full text Add to dashboard Cite

show abstract

“…All photographs examined were of the two highest quality categories as described in Wang et al (2012).…”

Section: Pigmentationmentioning

confidence: 99%

Diagnosability and description of a new subspecies of Indo-Pacific humpback dolphin, Sousa chinensis (Osbeck, 1765), from the Taiwan Strait

Wang

Yang²,

Hung³

2015

Zool. Stud.

Self Cite

View full text Add to dashboard Cite

Background: Subspecies recognition can affect how people (scientists and non-scientists alike) view organisms and thus has important implications for research on, as well as the conservation of, these entities. Recently, a small group of Indo-Pacific humpback dolphins was discovered inhabiting the waters off central western Taiwan. This geographically isolated population possesses pigmentation patterns that are subtly, but noticeably, different from their nearest conspecifics in the neighbouring waters of the Jiulong River Estuary and Pearl River Estuary of mainland China. Due to this population's low and declining numbers and the numerous threats it faces, it was assessed as critically endangered by the Red List of Threatened Species of the International Union for Conservation of Nature. The purpose of this study is to examine the degree of differentiation of the Taiwanese population to determine if subspecies recognition is warranted.

show abstract

“…A 2002 to 2004 line-transect survey resulted in a population estimate of 99 individuals (CV = 0.516; Wang et al 2007a) and an N min of 66 individuals. A recent mark-recapture study resulted in an estimate of 74 individuals (CV = 0.04; Wang et al 2012), with an N min of 71. No estimate of the maximum annual population growth rate is available for ETS Sousa.…”

Section: Consequences Of Fisheries Mortality For Conservationmentioning

confidence: 99%

“…Most evidence has shown that marine mammals can recover from small population sizes, as shown in Table 3. Although some individuals have shown signs of poor body condition, most photographically identified ETS Sousa still appear in good condition, and calves are born almost every year (Wang & Yang 2011, Wang et al 2012.…”

Section: Costs and Benefits Of Changing Fishing Gearsmentioning

confidence: 99%

Impacts of fisheries on the Critically Endangered humpback dolphin Sousa chinensis population in the eastern Taiwan Strait

Slooten¹,

Wang²,

Dungan³

et al. 2013

Endang. Species. Res.

View full text Add to dashboard Cite

Biological and fisheries data were analysed to assess the impact of fisheries mortality on a Critically Endangered subpopulation of <100 humpback dolphins Sousa chinensis in the eastern Taiwan Strait (ETS). Substantial interactions between ETS S. chinensis (hereafter Sousa) and fishing gear are known to cause dolphin mortality. In 2009, a total of 6318 motorised fishing vessels were operating from ports within Sousa habitats. An average of 32 fishing craft per kilometre was observed along a 200 km stretch of Sousa habitat. Based on a photo-identification catalogue, > 30% of the ETS Sousa subpopulation exhibited injuries caused by fishing gear. Three individuals were photographed with fishing gear attached to their bodies, and 1 dolphin was found dead with fresh injuries caused by fishing gear. To ensure recovery of ETS Sousa, mortality due to human causes should be reduced to <1 individual every 7 yr. Fisheries bycatch is the most serious threat to these dolphins and needs to be eliminated as soon as possible to avoid extinction. Preventing the use of trammel nets, other gillnets and trawling throughout their habitat would be the single most effective conservation measure for ETS Sousa in the short term. Other fishing methods are available, and using the most selective, sustainable fishing methods available will benefit not only dolphins but also fish stocks, seabirds and other species, as well as the fishing industry, which depends on these species for its long-term viability. However, in the short term, there are costs associated with switching to more selective fishing gear.

show abstract

Mark-Recapture Analysis of the Critically Endangered Eastern Taiwan Strait Population of Indo-Pacific Humpback Dolphins (Sousa Chinensis): Implications for Conservation

Cited by 46 publications

References 0 publications

Viability of the Critically Endangered eastern Taiwan Strait population of Indo-Pacific humpback dolphins Sousa chinensis

Viability of the Critically Endangered eastern Taiwan Strait population of Indo-Pacific humpback dolphins Sousa chinensis

Diagnosability and description of a new subspecies of Indo-Pacific humpback dolphin, Sousa chinensis (Osbeck, 1765), from the Taiwan Strait

Impacts of fisheries on the Critically Endangered humpback dolphin Sousa chinensis population in the eastern Taiwan Strait

Contact Info

Product

Resources

About