including 161 from the reaches above the dam (Fig. Recommendations
7). Commercial fishing has been closed since 1983,
and fishing for scientific or propagation purposes
produces annual catches of about 100 individuals. In
addition to fishing mortality, many individuals are
killed by the dam. and are discovered as carcasses
below it. The number of carcasses has declined as
the number of adult sized fish trapped above the
dam continues to decrease.
We tagged 57 adults collected from sites at Shashi
(51) and at Yichang (6) in 1983 and 1984 in order to
estimate the stock size. By the following year, we
had recaptured 6 individuals, including 4 from the
areas near the release sites and 2 from the sea near
the mouth of the Yangtze. Using Peterson's meth-
od, we estimated that the mean stock size of the
spawning stock of Chinese sturgeon was 2176 (946
and 4169 as 95% confidential intervals) in 1983 and
- Given alternate year spawning migrations,
the annual stock size migrating into the river was
about 1000 individuals.
No exact data on juveniles are available for years
prior 1981. However. the stock ofjuveniles has de-
creased at the Yangtze estuary. In the 1960s, this
stock supported a major commercial fishery but it Yangtze River
has declined to about 5000 fish per year (Wei et al.
1994). The construction of Gezhouba Dam greatly affect-
ed stocks of P. gladius and A. sinensis. If no mea-
Conservation efforts.– All commercial fishing has sures are taken, paddlefish will disappear in the
been banned since I983 and a series of protective middle and lower reaches of Yangtze in the very
measures have been taken, including setting up pro- near future, placing the species on the verge of ex-
tection stations along the river and a station at Yi- tinction. Wild populations ofA. dabryanusare de-
chang for artificial propagation and research. In clining despite protection. The typical anadromous
1988.A. sinensiswas listed as a state protected ani- species,A. sinensis,is increasingly threatened. As
mal in class I. In 1983, the first successfull artificial the largest dam ever constructed, The Three Gorg-
spawning was made by the Yangtze River Fisheries es Project, nears completion (1997), the habitat for
Institute (Fu et al. 1985). Since then, an average of both species of sturgeons and the paddlefish will be
250 000 larvae and some juveniles have been further harmed. This huge dam will be 175 m high
stocked into the river annually. The total number and is only 47 km upstream from the Gezhouba
stocked was 2.8 million larvae and 17 000 juveniles Dam. Furthermore, it will use 1.3 million tons of
(size2–10g) from 1983 through 1993. Both thegen gravel and rocks from the reach below Gezhouba
eral public and fishermen are now protective of Dam as construction material (Ke & Wei 1993), di-
sturgeon, and willingly release incidental catches. rectly damaging the largest known existing spawn-
For instance. in just the Yichang section. we are ing ground for Chinese sturgeon and many other
aware of 148 incidental catches that were released commercial fishes. Despite these serious impacts.
between 1986 and 1993. some measures can and should be taken, such as: (1)
establishing protected areas for juvenile Chinese
Amur RiverStocks ofHuso dauricusandAcipenser schrenckii in
the Amur River are declining dramatically due to
overfishing. If we ignore this situation, then we will
loose the sturgeon fishery and perhaps even both
species. Loss of sturgeon fisheries has occurred in
many other places (Hol^
cík et al. 1989, Smith 1985.
Galbreath 1985, Folz & Meyers 1985, Pinter 1991).
We recommend that the following measures be im-
mediately taken: (1) modify existing regulations for
sturgeon fishery management; (2) reduce fishing ef-
fort. including restrictions onthe number of boats,
the type of gear used. and the maximum allowable
catch; (3)strictly forbid fishing juveniles and to
strengthen artificial propagation; (4) strengthen
scientific investigations on the stock to establish a
rational maximum allowable catch; (5) work out a
joint pledge for sturgeon conservation in the shared
waters of China and Russia.