137
revealed interesting features about the status of
the two signifi cant lakes of the region, namely,
the Qinghai Lake (Qinghai) and the Bosten Lake
(Xinjiang).
Climate
The region mostly has an arid climate, strongly
infl uenced by altitude (Liu 1980 ; Liu et al. 1989 ;
Wang 1987 ; Williams 1991 ). The average temperatures ranges from −10 to −15 °C, while the
extreme temperatures recorded for all China
(−51.5 to 48.9 °C) are also from this area. Annual
precipitation ranges from 600 to 1,000 mm on the
northern slopes.
Limnology
A limnological overview of the region had been
given by Williams ( 1991 ).
Some of the large lakes of the region are
(a) Qinghai (Qinghai Hu), Gyaring (Zhalin),
Ngoring (Elin) and Keluke in Qinghai Province;
(b) Bosten, Ulungur, Ebinur and Sayram
(Shailimu) in Xinjiang Province; and (c)Yamdrok,
Namucuo and Banggong in Xizang Province. On
the other hand, small lakes are common and may
be permanent or ephemeral, depending on local
precipitation and their proximity to rivers.
However, polymictic circulation pattern prevails
in the shallow lakes, but the deeper ones tend to
be dimictic. Salinities range from freshwater to
crystallising brines, and the water chemistry is
predominantly sodium chloride although calcium,
magnesium, bicarbonate, carbonate and sulphate
are important in some instances. Values of pH
generally are high and often above 9.0. Plant
nutrient concentrations are variable in waters
throughout the region, perhaps, refl ecting land
use; and the lakes, accordingly, range from oligotrophic to eutrophic status. Typical standing crops
of benthos, AM, phytoplankton and zooplankton
are associated with some lakes.
Biological Basis for Fish Production
Notwithstanding the above, in Xinjiang Province ,
the most recent investigation has been a survey
of 36 diverse environments in 1985–1987 by
Liu et al. ( 1989 ). They recorded 157 species of
phytoplankton, including 60 Bacillariophyta
(predominantly Cyclotella , Navicula and Synedra )
and 53 Chlorophyta (e.g . Ankistrodesmus , Oocystis ,
Scenedesmus ). Standing crops averaged 3.11
million (range 5–10 million) cells/l or 3.353
(0.029–15.888) mg l
−1
. Zooplankton species
numbered 76, including 26 protozoans (e.g.
Cyclidium , Strombidium , Tintinnidium ), 10 copepods (e.g. Arctodiaptomus salinus , Cyclops vicinus
vicinus ), 15 cladocerans (e.g. Bosmina longirostris ,
Diaphanosoma brachyurum ) and 25 rotifers
(e.g. Keratella cochlearis , Polyarthra euryptera ).
Standing crops averaged 6263 (29–39,977)
organisms/l, with biomass 1.7624 (0.043–10.869)
mg l
−1 and an equivalent fi sh biomass 55 (1.2–266)
kg ha
−1
. The benthos included 130 species, including oligochaetes (3 families, 9 genera and 18
species, or 14 % of all benthic species), insects (28,
59, 88, 68 %) and molluscs (5, 7, 15, 6 %).
Dominant species were Tubifex tubifex and
Limnodrilus helveticus (Oligochaeta), Procladius
choreus , Cryptochironomus digitatus , C . conjugens and Chironomus plumosus (Diptera:
Chironomidae) and Gyraulus albus , Radix peregra
and R . swinhoei (Mollusca). The average benthic
biomass was 1943 organisms m
−2 (12.587 g m
−2
),
including 7.673 g m
−2 molluscan biomass and
1.073 g m
−2 oligochaete biomass, with an equivalent fi sh biomass of 8.2 kg ha
−1
. AM were represented by 107 species (30 families), notably Acorus
calamus , Phragmites communis , Myriophyllum
ussuriense , Potamogeton pectinatus and P. malaiannus . The average biomass was 440 (17–3298) g
m
−2 and equivalent fi sh biomass 59.7 (13.8–130.5)
kg ha
−1
.
There are no systematic data for plants or
invertebrates in Xizang Province , but there are
458 recorded species of Protozoa, 208 Rotifera
and 59 Crustacea, and the estimated potential fi sh
biomass is 49.2 kg ha
−1 (lakes 53.6, reservoirs
47.4, swamps 40.8: Anon 1981 ).
Ichthyofauna
Western China has a comparatively small fi sh
fauna of 190 species, most of them members of
the Central Asian Plateau Complex (Li 1981 ).
There are many taxonomic works dating from the
nineteenth century, including key papers by
Günther ( 1859 –1870, 1876 ), Kessler ( 1876 ,
6.9 High Altitude (HA) Lentic Bodies
revealed interesting features about the status of
the two signifi cant lakes of the region, namely,
the Qinghai Lake (Qinghai) and the Bosten Lake
(Xinjiang).
Climate
The region mostly has an arid climate, strongly
infl uenced by altitude (Liu 1980 ; Liu et al. 1989 ;
Wang 1987 ; Williams 1991 ). The average temperatures ranges from −10 to −15 °C, while the
extreme temperatures recorded for all China
(−51.5 to 48.9 °C) are also from this area. Annual
precipitation ranges from 600 to 1,000 mm on the
northern slopes.
Limnology
A limnological overview of the region had been
given by Williams ( 1991 ).
Some of the large lakes of the region are
(a) Qinghai (Qinghai Hu), Gyaring (Zhalin),
Ngoring (Elin) and Keluke in Qinghai Province;
(b) Bosten, Ulungur, Ebinur and Sayram
(Shailimu) in Xinjiang Province; and (c)Yamdrok,
Namucuo and Banggong in Xizang Province. On
the other hand, small lakes are common and may
be permanent or ephemeral, depending on local
precipitation and their proximity to rivers.
However, polymictic circulation pattern prevails
in the shallow lakes, but the deeper ones tend to
be dimictic. Salinities range from freshwater to
crystallising brines, and the water chemistry is
predominantly sodium chloride although calcium,
magnesium, bicarbonate, carbonate and sulphate
are important in some instances. Values of pH
generally are high and often above 9.0. Plant
nutrient concentrations are variable in waters
throughout the region, perhaps, refl ecting land
use; and the lakes, accordingly, range from oligotrophic to eutrophic status. Typical standing crops
of benthos, AM, phytoplankton and zooplankton
are associated with some lakes.
Biological Basis for Fish Production
Notwithstanding the above, in Xinjiang Province ,
the most recent investigation has been a survey
of 36 diverse environments in 1985–1987 by
Liu et al. ( 1989 ). They recorded 157 species of
phytoplankton, including 60 Bacillariophyta
(predominantly Cyclotella , Navicula and Synedra )
and 53 Chlorophyta (e.g . Ankistrodesmus , Oocystis ,
Scenedesmus ). Standing crops averaged 3.11
million (range 5–10 million) cells/l or 3.353
(0.029–15.888) mg l
−1
. Zooplankton species
numbered 76, including 26 protozoans (e.g.
Cyclidium , Strombidium , Tintinnidium ), 10 copepods (e.g. Arctodiaptomus salinus , Cyclops vicinus
vicinus ), 15 cladocerans (e.g. Bosmina longirostris ,
Diaphanosoma brachyurum ) and 25 rotifers
(e.g. Keratella cochlearis , Polyarthra euryptera ).
Standing crops averaged 6263 (29–39,977)
organisms/l, with biomass 1.7624 (0.043–10.869)
mg l
−1 and an equivalent fi sh biomass 55 (1.2–266)
kg ha
−1
. The benthos included 130 species, including oligochaetes (3 families, 9 genera and 18
species, or 14 % of all benthic species), insects (28,
59, 88, 68 %) and molluscs (5, 7, 15, 6 %).
Dominant species were Tubifex tubifex and
Limnodrilus helveticus (Oligochaeta), Procladius
choreus , Cryptochironomus digitatus , C . conjugens and Chironomus plumosus (Diptera:
Chironomidae) and Gyraulus albus , Radix peregra
and R . swinhoei (Mollusca). The average benthic
biomass was 1943 organisms m
−2 (12.587 g m
−2
),
including 7.673 g m
−2 molluscan biomass and
1.073 g m
−2 oligochaete biomass, with an equivalent fi sh biomass of 8.2 kg ha
−1
. AM were represented by 107 species (30 families), notably Acorus
calamus , Phragmites communis , Myriophyllum
ussuriense , Potamogeton pectinatus and P. malaiannus . The average biomass was 440 (17–3298) g
m
−2 and equivalent fi sh biomass 59.7 (13.8–130.5)
kg ha
−1
.
There are no systematic data for plants or
invertebrates in Xizang Province , but there are
458 recorded species of Protozoa, 208 Rotifera
and 59 Crustacea, and the estimated potential fi sh
biomass is 49.2 kg ha
−1 (lakes 53.6, reservoirs
47.4, swamps 40.8: Anon 1981 ).
Ichthyofauna
Western China has a comparatively small fi sh
fauna of 190 species, most of them members of
the Central Asian Plateau Complex (Li 1981 ).
There are many taxonomic works dating from the
nineteenth century, including key papers by
Günther ( 1859 –1870, 1876 ), Kessler ( 1876 ,
6.9 High Altitude (HA) Lentic Bodies