71
UKh has two big divisions, namely, (a) the
Kumaon Division and (b) the Garhwal Division.
The former includes the Lakes Nainital, Bhimtal,
Naukuchiatal, Khurpatal and Sat Tal. These lie at
1,220–1,937 m MSL within a short distance of
each other and within a 25-km radius from the
city of Nainital. Most of these are small lakes.
The largest one, Bhimtal, is a 72-ha lake, while
the Lake Naukuchiatal is the deepest, with a
maximum depth of 40.8 m. On the other hand,
the lakes in the Garhwal Division are situated at
little higher altitudes, in general. Some of these
are Devaria Tal, Dhalipur Lake, Hem Kund,
Kashni Tal, Kedartal and so on.
The Kumaon lake water is generally slightly
alkaline. The water stratifi es in spring and mixes
during winter. Lake Nainital is eutrophic, with
288, 512 and 22.5 mg l
−1 of CO 3 , N and P, respectively (Sharma and Pant 1985). Bhimtal and
Naukuchiatal have moderate levels of nutrients
and are mesotrophic. Lakes Khurpatal and Sat
Tal are poor in nutrients. The rising level of nitrogen in Lake Nainital indicates an increasing trend
of pollution. As such, there has been an increase
in higher biological (organic) matter production
and its deposition on the lake bottom. This, sometimes, results in anoxic conditions in the bottom
water. Hence, fi sh mortality in Lake Nainital and
Lake Naukuchiatal is now quite a regular feature
during winter.
Fish
The Kumaon lakes reveal fi sh yield (FY) generally
0.7–9.3 kg ha
−1
. The major fi sh species being the
introduced IMC, common carp, indigenous mahseers, etc. Johri et al . (1989) had worked on the
fi sh catch for the period 1983–1988 for Bhimtal,
Naukuchiatal and Sat Tal, which are managed by
the State Department of Fisheries. Lake Nainital,
on the other hand, is managed by the Nainital town
municipality, which also, perhaps, monitors the
input of pollutants into this lake.
Mahseers ( Tor tor and T. putitora ) generally
dominate the catches in Bhimtal and Naukuchiatal,
with 59.5 and 45.0 %, respectively, followed by the
common carp with 34.8 and 31.5 %, respectively,
of the total catch. In Sat Tal, however, the common
carp formed 22.9 % of the total catch. The IMC
( Labeo rohita , Cirrhinus mrigala and Catla
catla) , sometimes, dominate the catches in Sat Tal
with 64.1 % of the total catch. Schizothoracines
(e.g. Schizothorax richardsonii ) represented 0.73
and 0.95 % in lakes Bhimtal and Naukuchiatal but
were absent in Sat Tal. Bhimtal seems to provide
good conditions for catla and rohu and Naukuchiatal
for mrigal. The low yield for Lake Naukuchiatal
seems to result from the lower fi shing intensity. As
a remedy, it has been proposed to regularly stock
this lake with fi ngerlings of mahseer, common
carp, IMC, etc. Stocking the Kumaon lakes is
considered essential for increasing fi sh yields,
which, it is estimated, could be increased to
25–50 kg ha
−1 year
−1
(Johri et al. 1989).
Details of HA lakes of India, including HA
lakes in the provinces of Sikkim, Uttarakhand,
HP and J&K, have been dealt with under
Sect. 6.9 .
6.1.10 Lakes in South America
6.1.10.1 Lake Titicaca
Lake Titicaca is the largest lake in South
America. It is situated at 3,803–3,815 m MSL
on the Andean Altiplano between Bolivia and
Peru. This lake lies at a latitude of about 16° S.
The lake is fed by fi ve rivers and many minor
streams. It drains out via the Rio Desaguadero
to Lake Poopo which is shallow, salty and,
probably, overfl ows intermittently into the
Coipasa salt pans.
The total area of Lake Titicaca is 7,600–
8,100 km
2 , three-quarters of which (6,315 km
2 ) is
a deep, steep-sided basin with a maximum depth
of 281 m and a mean depth of 107 m. The shallow areas contain a rather different ecosystem,
including extensive areas of Scirpus marsh. The
shallow areas are separated from the main lake by
constrictions in the shoreline. From the very
southern end of the bay, at Guaqui, a railway runs
to La Paz, the capital of Bolivia, and a boat service runs across the lake. The railhead of the line
climbs the western slope of the Andes from the
coast of Peru. The natural vegetation of the area,
immediately surrounding the lake, is a form of
grassland known as ‘puna’. However, most of the
6.1 Lakes of Tropical Latitudes
UKh has two big divisions, namely, (a) the
Kumaon Division and (b) the Garhwal Division.
The former includes the Lakes Nainital, Bhimtal,
Naukuchiatal, Khurpatal and Sat Tal. These lie at
1,220–1,937 m MSL within a short distance of
each other and within a 25-km radius from the
city of Nainital. Most of these are small lakes.
The largest one, Bhimtal, is a 72-ha lake, while
the Lake Naukuchiatal is the deepest, with a
maximum depth of 40.8 m. On the other hand,
the lakes in the Garhwal Division are situated at
little higher altitudes, in general. Some of these
are Devaria Tal, Dhalipur Lake, Hem Kund,
Kashni Tal, Kedartal and so on.
The Kumaon lake water is generally slightly
alkaline. The water stratifi es in spring and mixes
during winter. Lake Nainital is eutrophic, with
288, 512 and 22.5 mg l
−1 of CO 3 , N and P, respectively (Sharma and Pant 1985). Bhimtal and
Naukuchiatal have moderate levels of nutrients
and are mesotrophic. Lakes Khurpatal and Sat
Tal are poor in nutrients. The rising level of nitrogen in Lake Nainital indicates an increasing trend
of pollution. As such, there has been an increase
in higher biological (organic) matter production
and its deposition on the lake bottom. This, sometimes, results in anoxic conditions in the bottom
water. Hence, fi sh mortality in Lake Nainital and
Lake Naukuchiatal is now quite a regular feature
during winter.
Fish
The Kumaon lakes reveal fi sh yield (FY) generally
0.7–9.3 kg ha
−1
. The major fi sh species being the
introduced IMC, common carp, indigenous mahseers, etc. Johri et al . (1989) had worked on the
fi sh catch for the period 1983–1988 for Bhimtal,
Naukuchiatal and Sat Tal, which are managed by
the State Department of Fisheries. Lake Nainital,
on the other hand, is managed by the Nainital town
municipality, which also, perhaps, monitors the
input of pollutants into this lake.
Mahseers ( Tor tor and T. putitora ) generally
dominate the catches in Bhimtal and Naukuchiatal,
with 59.5 and 45.0 %, respectively, followed by the
common carp with 34.8 and 31.5 %, respectively,
of the total catch. In Sat Tal, however, the common
carp formed 22.9 % of the total catch. The IMC
( Labeo rohita , Cirrhinus mrigala and Catla
catla) , sometimes, dominate the catches in Sat Tal
with 64.1 % of the total catch. Schizothoracines
(e.g. Schizothorax richardsonii ) represented 0.73
and 0.95 % in lakes Bhimtal and Naukuchiatal but
were absent in Sat Tal. Bhimtal seems to provide
good conditions for catla and rohu and Naukuchiatal
for mrigal. The low yield for Lake Naukuchiatal
seems to result from the lower fi shing intensity. As
a remedy, it has been proposed to regularly stock
this lake with fi ngerlings of mahseer, common
carp, IMC, etc. Stocking the Kumaon lakes is
considered essential for increasing fi sh yields,
which, it is estimated, could be increased to
25–50 kg ha
−1 year
−1
(Johri et al. 1989).
Details of HA lakes of India, including HA
lakes in the provinces of Sikkim, Uttarakhand,
HP and J&K, have been dealt with under
Sect. 6.9 .
6.1.10 Lakes in South America
6.1.10.1 Lake Titicaca
Lake Titicaca is the largest lake in South
America. It is situated at 3,803–3,815 m MSL
on the Andean Altiplano between Bolivia and
Peru. This lake lies at a latitude of about 16° S.
The lake is fed by fi ve rivers and many minor
streams. It drains out via the Rio Desaguadero
to Lake Poopo which is shallow, salty and,
probably, overfl ows intermittently into the
Coipasa salt pans.
The total area of Lake Titicaca is 7,600–
8,100 km
2 , three-quarters of which (6,315 km
2 ) is
a deep, steep-sided basin with a maximum depth
of 281 m and a mean depth of 107 m. The shallow areas contain a rather different ecosystem,
including extensive areas of Scirpus marsh. The
shallow areas are separated from the main lake by
constrictions in the shoreline. From the very
southern end of the bay, at Guaqui, a railway runs
to La Paz, the capital of Bolivia, and a boat service runs across the lake. The railhead of the line
climbs the western slope of the Andes from the
coast of Peru. The natural vegetation of the area,
immediately surrounding the lake, is a form of
grassland known as ‘puna’. However, most of the
6.1 Lakes of Tropical Latitudes