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2006; Yang et al., 2006). Some authors even chose to advocate the supposed inevitability of
the baiji's demise (Yang et al., 2006), contrasting markedly with the extreme caution typically
displayed by conservationists when ruling other species to be beyond help (Butchart et al.,
2006; Roberts & Kitchener, 2006). However, whilst open discussion and debate remain
invaluable in refining and establishing effective conservation strategies for threatened species,
a more dynamic international response was also ultimately required to prevent the baiji's
extinction.
Wider Conservation Lessons
Although the baiji is now likely to be extinct, the mid-lower Yangtze drainage still
contains many other increasingly threatened endemic species (Qiu & Chen, 1988; Zhong &
Power, 1997; Fu, 2003), several of which are also ‗charismatic' megafaunal taxa (e.g.
Yangtze paddlefish
Psephurus gladius
; Yangtze giant soft-shell turtle
Rafetus swinhoei
;
Chinese alligator
Alligator sinensis
; see Wei et al., 1997; Thorbjarnarson et al., 2002; Xie,
2003; Stone, 2007). Data collected during the 2006 range-wide baiji survey indicate that the
Yangtze finless porpoise, the world's only freshwater porpoise, has experienced a population
decline of over 50% since the early 1990s (Zhao et al., 2008), and population viability
analysis (PVA) conducted a decade ago suggested that this cetacean was likely to become
extinct within 24-94 years (Zhang & Wang, 1999), although the relative importance of
different anthropogenic threat factors and the dynamics of this population decline again
remain poorly understood. Given the continuing massive-scale intensification of human
impacts on this freshwater system, it is difficult to suggest optimal recovery strategies to
conserve its remaining unique biodiversity, especially since most of these other threatened
species have been the focus of far less national and international conservation attention than
was received by the baiji in recent decades. It is likely that
ex situ
conservation will also be
required to prevent the further extinctions of many Yangtze species. In particular, the failure
of existing
in situ
conservation measures to prevent the disappearance of the baiji suggests
that it is also highly unlikely that the river's finless porpoise population will be able to persist
without an intensive and well-managed
ex situ
recovery program. Semi-natural breeding
groups of porpoises have already been established at both Tian'e-Zhou and Tongling (despite
the ongoing problems with on-site cetacean mortality and human-wildlife conflict described
above), and further introductions have also been proposed for the Hei-Wa-Wu oxbow (Hubei
Province) and the Three Gorges Dam reservoir. However, more unified efforts - and greater
international support - are once again required if the conservation of the porpoise is to stand a
strong chance of success, and unlike the baiji, this species is still only listed in the Second
Category of the List of National Protected Wild Animals (Sheng, 1998a).
The implications of the baiji's probable extinction for the conservation of other
threatened freshwater cetaceans, and indeed other globally threatened species, are more
general. Accidental by-catch in fishing gear, the likely main extinction driver for the baiji,
remains the principal cause of mortality in many populations of small cetaceans worldwide
(Reeves et al., 2003). However, river dolphins in other geographical regions, notably other
Asian river systems also experiencing large-scale and escalating anthropogenic impacts, are
declining due to a range of extinction drivers which may vary in relative severity compared to
the threats faced by cetaceans in the Yangtze. For example, in addition to accidental by-catch
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