141
200,000 t from 1958 to 1991, and generally has
contributed more than 85 % of annual aquatic
production in Qinghai Province (Walker et al.
1996 ). In addition, the lake attracts thousands of
cormorants ( Phalacrocorax carbo sinensis ),
gulls ( Larus brunnicephalus , L. ichthyaetus ) and
other species that feed upon the fi ngerlings and
fry of naked carp.
A comprehensive report on Qinghai Lake , the
largest lake in China, is provided by Academia
Sinica ( 1979 ) (vide Melack 1983 ; Kelts et al .
1989 ; Walker et al. 1996 ).
Fishery
Notwithstanding the above, little details of the
fi shery of this lake are briefl y given below.
History
There has been a fi shery for spawning naked carp
in the Buha and Shaliu rivers since at least the
nineteenth century, when the fi sh were abundant
and easily captured by a variety of simple methods. In 1958, the fi shery was opened to commercial exploitation and trawling and gillnetting
became the main methods of capture.
Long-Term Yield
The catches peaked at 28,523 t in 1960 but
declined to about 4,000 t some fi ve years later.
Catches between 1965 and 1980 fl uctuated
between 3,639 and 4,979 t, but after 1980, there
were indications of a slow decline. There was a
total annual catch of about 3,000 t on average.
Piscivorous birds are believed to capture another
700 t (Hu 1975 ; Zhao 1982 ). Zhang and Chen
( 1980 ) used the Beverton–Holt Dynamic Pool
Model and catch data available to 1976 to
estimate the sustainable annual yield as 4,791 t.
This assumed an age of fi rst capture of 10 years
and a fi shing mortality coeffi cient of 1.25.
Some consideration has been given to the
introduction of other fi sh species to diversify the
Qinghai Lake fi shery. In the 1960s, unsuccessful
attempts were made to introduce two species of
mullet ( Mugil soiuy , M . sp.: e.g. Li 1959 ), and it
is possible that introduction of rainbow trout may
be considered in future, if recent developments in
aquaculture are supported (Edwards 1992 ). The
harsh environment militates against the survival
of other species. Further, the fact that G. przewalskii
is endemic to the lake also must argue against
further introductions. The entire Qinghai Lake
ecosystem would be irrevocably changed by
introduced fi sh species.
Bosten Lake
Bosten Lake, area 100,000 ha, lying at 1,046 m
MSL, between 87° 29′ E and 42° 17′ N, is an HA
lake in Xinjiang Province of China. It has a surface area (km
2
), volume (10
8 m
3 ), maximum
depth (m) and average depth (m) of 930, 84, 16
and 9, respectively. Annual rainfall and evaporation are 50 and 2,100 mm year
−1 , respectively.
Water chemistry generally reveals average temperature 11.4 °C, transparency 0.9 m, pH 8.2, DO
7.4 mg l
−1
, TA 4.8 mg l
−1 , TH 38.3 mg l
−1 , NO 3
0.007 mg l
−1
, PO 4 0.039 mg l
−1 ; phytoplankton
and zooplankton biomass are 1.24 and 1.48 g m
−3 ,
respectively, and AM biomass 19.5 g m
−2 . In
addition, there are several smaller lakes in the
neighbouring areas having a total area of 3300 ha.
The climate annually provides about 180 days
with temperatures above 10 °C; and hence, it is
favourable for the growth of cyprinids. Average
air temperatures range from −15.5 °C (minimum
−30.4 °C) in January to 24 °C (maximum
39.2 °C) in July. Average annual precipitation is
66 mm and evaporation is 1,983 mm. Despite the
above situation, the fi shery of the lake had been
adversely affected by changes in the salinity and
surface level of the lake. Since the 1950s, irrigation projects had been diverting water from the
lake, which had resulted in a fall of 2 m in the
water level and a reduction in the stands of littoral AM and fi sh spawning areas. The salinity has
increased from 0.39 in 1958 to 1.84 g l
−1 in 1983.
Fauna and Flora
Fifty-four genera of phytoplankton have been
recorded from Bosten Lake. Some of these are
Ceratium hirundinella , Chodatella sp., Navicula
sp., etc. The phytoplankton cell densities usually range from 25 to 67/l with maximum
recorded 1.280 million/l. Conversely, 39 zooplanktonic genera have been recorded from the
lake with densities 1,500–2,000/l (minimum
6.9 High Altitude (HA) Lentic Bodies
200,000 t from 1958 to 1991, and generally has
contributed more than 85 % of annual aquatic
production in Qinghai Province (Walker et al.
1996 ). In addition, the lake attracts thousands of
cormorants ( Phalacrocorax carbo sinensis ),
gulls ( Larus brunnicephalus , L. ichthyaetus ) and
other species that feed upon the fi ngerlings and
fry of naked carp.
A comprehensive report on Qinghai Lake , the
largest lake in China, is provided by Academia
Sinica ( 1979 ) (vide Melack 1983 ; Kelts et al .
1989 ; Walker et al. 1996 ).
Fishery
Notwithstanding the above, little details of the
fi shery of this lake are briefl y given below.
History
There has been a fi shery for spawning naked carp
in the Buha and Shaliu rivers since at least the
nineteenth century, when the fi sh were abundant
and easily captured by a variety of simple methods. In 1958, the fi shery was opened to commercial exploitation and trawling and gillnetting
became the main methods of capture.
Long-Term Yield
The catches peaked at 28,523 t in 1960 but
declined to about 4,000 t some fi ve years later.
Catches between 1965 and 1980 fl uctuated
between 3,639 and 4,979 t, but after 1980, there
were indications of a slow decline. There was a
total annual catch of about 3,000 t on average.
Piscivorous birds are believed to capture another
700 t (Hu 1975 ; Zhao 1982 ). Zhang and Chen
( 1980 ) used the Beverton–Holt Dynamic Pool
Model and catch data available to 1976 to
estimate the sustainable annual yield as 4,791 t.
This assumed an age of fi rst capture of 10 years
and a fi shing mortality coeffi cient of 1.25.
Some consideration has been given to the
introduction of other fi sh species to diversify the
Qinghai Lake fi shery. In the 1960s, unsuccessful
attempts were made to introduce two species of
mullet ( Mugil soiuy , M . sp.: e.g. Li 1959 ), and it
is possible that introduction of rainbow trout may
be considered in future, if recent developments in
aquaculture are supported (Edwards 1992 ). The
harsh environment militates against the survival
of other species. Further, the fact that G. przewalskii
is endemic to the lake also must argue against
further introductions. The entire Qinghai Lake
ecosystem would be irrevocably changed by
introduced fi sh species.
Bosten Lake
Bosten Lake, area 100,000 ha, lying at 1,046 m
MSL, between 87° 29′ E and 42° 17′ N, is an HA
lake in Xinjiang Province of China. It has a surface area (km
2
), volume (10
8 m
3 ), maximum
depth (m) and average depth (m) of 930, 84, 16
and 9, respectively. Annual rainfall and evaporation are 50 and 2,100 mm year
−1 , respectively.
Water chemistry generally reveals average temperature 11.4 °C, transparency 0.9 m, pH 8.2, DO
7.4 mg l
−1
, TA 4.8 mg l
−1 , TH 38.3 mg l
−1 , NO 3
0.007 mg l
−1
, PO 4 0.039 mg l
−1 ; phytoplankton
and zooplankton biomass are 1.24 and 1.48 g m
−3 ,
respectively, and AM biomass 19.5 g m
−2 . In
addition, there are several smaller lakes in the
neighbouring areas having a total area of 3300 ha.
The climate annually provides about 180 days
with temperatures above 10 °C; and hence, it is
favourable for the growth of cyprinids. Average
air temperatures range from −15.5 °C (minimum
−30.4 °C) in January to 24 °C (maximum
39.2 °C) in July. Average annual precipitation is
66 mm and evaporation is 1,983 mm. Despite the
above situation, the fi shery of the lake had been
adversely affected by changes in the salinity and
surface level of the lake. Since the 1950s, irrigation projects had been diverting water from the
lake, which had resulted in a fall of 2 m in the
water level and a reduction in the stands of littoral AM and fi sh spawning areas. The salinity has
increased from 0.39 in 1958 to 1.84 g l
−1 in 1983.
Fauna and Flora
Fifty-four genera of phytoplankton have been
recorded from Bosten Lake. Some of these are
Ceratium hirundinella , Chodatella sp., Navicula
sp., etc. The phytoplankton cell densities usually range from 25 to 67/l with maximum
recorded 1.280 million/l. Conversely, 39 zooplanktonic genera have been recorded from the
lake with densities 1,500–2,000/l (minimum
6.9 High Altitude (HA) Lentic Bodies