51813_Sturgeon biodioversity an.PDF

168000 juveniles (1.0 to 1.5 or 20 to 30gBW) were
stockedinto the Amurriver from1988 t o 1991, and
the number ofyoung sturgeon in the Amur River
seemed to beincreasing through1991 (Chen&
Zhou1992).

16.0 kgBW.Major research wasdone from1972 to

1975.Thisspecies iseasily propagated, and has ex-

cellentcommercial aquaculturepotential. The na-

tive population,however, sharply declined in the

last twodecades.Somefishstilloccur in theupper

middle reach but few occurred in reachesbelow the

Gezhouba Dam in recentyears. SeeZhuang et al.

(1996,thisvolume) forareview of this species.

Chinese paddlefish, Psephurus gladius

The Chinese paddlefish is characterized by its

sword-like rostrum and severalosteological fea-

tures that distinguish itfromotherfossil and living

paddlefishes(Grande&Bemis1991,1996, Bemis et

al. 1997 this volume). Rostral length (RL) is as much

as 114 to 113 times thetotallength(TL =–17.134+

3.8957 RL,N=16, R=0.9841,S=9.9181,F=

249.366). Detailed biologicalinvestigations are im-

possiblebecausePsephurusis now very rare. Migra-

tion patterns andspawning sites of theChinese pad-

dlefish areunknown, although ithistorically oc-

curred in theEastChina Sea,soit is presumably

anadromous (Anonymous 1988). It is also recorded

from the YellowRiver andYellow Sea (Zhu et al.

1963, Li 1965).

Within the YangtzeRiver, Chinese paddlefish

were commonly found in the mainstream, and

sometimes in its tributaries including Tuojiang,

Mingjiang, Jialinjiang, Qiantangjiang and Yong-

jiang rivers, andDongting andPoyanglakes(Anon-

Yangtze River

The Yangtze(also known as the Chang Jiang) arises

in southwestern China and flows 5500 km across the

country toreach theEastChina Sea near Shanghai

(Figure1).Based on its outflow, theYangtzeisthe

fourth largestriver in theworld, surpassed only by

the Amazon, Congo, and Indus rivers.Near the

headwaters, the mainstream ofthe Yangtze is

known as the Tongtian River; its eastward course

towardSichuan is known as the Jingsha River; as it

passes throughSichuan it becomes known as the

Yangtze. It passes through some of the most densely

populated areas of the planet, yet itretainsthree

nativespecies ofAcipenseriformes. This situation is

now deterioratingrapidly, and allthree species in

the Yangtze River have been listed as state protect-

ed animals in CategoryI.

Dabry’s sturgeon,Acipenserdabryanus

Dabry’s sturgeon is a freshwater species that occurs

only in the middle andupperreaches of theYangtze

River (Figure 1).It reaches at least 130 cm TL and

Table 3. Composition of spawning stock of Huso dauricus in the middle reach of the Amur River by sex.