Cold water Fisheries occupy an important place amongst the freshwater fishes of India. The cold water fisheries deal with fisheries activity in water where temperature of water ranges from 5 to 25 degrees centigrade. The water temperature under cold water fisheries should not be more than 25°C even in summer

1. COLD WATER FISH AND FISHERIES IN INDIA
The Himalayas, which cover 594 400 km2, run for about 2 500 km
from west to east, between Nanga Parbat (8 126 m) in the west and
Namcha Barwa (7 756 m) in the east. This mountain system is
bordered in the west by the Karakoram Mountains and in the north
by the high Plateau of Tibet. The width from the south to the north
varies between 200 and 400 km. From south to north one can
distinguish four parallel and longitudinal mountain belts of varying
width, each having distinct physiographic features and its own
geological history: the Siwaliks, the Lesser Himalaya, the Greater
Himalaya and the Trans-Himalaya (Sehgal, 1999). The Himalayas are
drained by 19 major rivers (Fig. 4), of which the Indus and the
Brahmaputra are the longest, each having a mountain catchment of
about 160 000 km2. Of the remaining 17 rivers five belong to the
Indus system, of which the Beas and the Sutlej have a total
catchment of 80 000 km2, nine(Ganga, Yamuna, Ram Ganga, Kali-
Sharda, Karnali, Rapti, Gandak, Bhagmati, Kosi) belong to the Ganga
system, draining nearly 150 000 km2. The Ganga has five source
rivers (Bhagirathi,Mandakini, Alaknanda, Dhauliganga, Pindar). A
number of rivers enter from within India and from Bhutan. The
Brahmaputra (known as Yarlung Zangbo Jiang, or Tsangpo, in China)
has a catchment of about 110 000 km2. Most of these rivers flow in
deep valleys until they exit the mountains.

2. The Himalayas and its principal rivers
(from Sehgal, 1999)

3. The fish species distribution in the Himalayan streams depends on
the flow rate, nature and substratum, water temperature, and the
availability of food. In the torrential streams Sehgal(1988) identified
several zones on the basis of the dominant fish species and the
hydrographicalfeatures:
(i)headwater zoneinhabited by rheophilic species of loaches and catfi
shes(Nemacheilus gracilis, N. stoliczkae and Glyptosternum
reticulatum ).
(ii) large stream zone, formed by the joining of headwater streams,
inhabited by Diptychus maculatus and Nemacheilus spp. In the upper
reaches of the mosttorrential section of this zone, the rheophilic
species of snow trouts,Schizothoraichthysesocinus,S. progastus,
Schizothorax richardsonii.
and Schizopygopsis stoliczkae,occur.The intermediate reaches of the
large stream zone are frequented by Schizothoraxlongipinnis, S.
planifrons and S. micropogon.The least rapid reaches of this zone
areoccupied by Garra gotyla, Crossocheilus diplochilus, Labeo dero
and L. dyocheilus.
(iii)slow moving meandering zoneinhabited by a large number of cold
or eurythermalspecies such as Barilius spp,Tor spp, catfishes,
homalopterid fish (Homaloptera spp) and snakeheads (Channa
spp).
Menon (1954) related the distribution of Himalayan fish to
morphological characteristics which enable them to inhabit the
torrential streams. He recognised six major groups:
(a) fish dwelling in shallow, clear cold water in the foothills without
any striking modification to current:
Labeo,Tor, Barilius and Puntius.

4. (b) fish inhabiting the bottom water layers in deep fast current,
with powerful muscular cylindrical bodies: schizothoracines and the i
ntroduced trout.
(c) fishsheltering among pebbles and stones to ward off the strong
current:
Crossocheilus diplochilus.
(d) fish sheltering among pebbles and shingles in shallows, with
special attachment devices:
the loaches Nemacheilus, Botia and Amblyceps.
(e) fish which cling to exposed surfaces of barerocks in lower current,
with adhesive organs on their ventral surface for attachment to
rocks:
Garra, Glyptothorax and Glyptosternum.
(f) fish which cling to the exposed surfaces of bare rocks in fast
current, with limpet-shaped bodies and mouth, gills and fins highly
modified to suit the habitat: Balitora
The need for shelter from the current has led to territoriality.
Mahseers and schizothoracines chase intruders to defend the limited
food resource and available shelter. During the winter, when the
water level is at its lowest and water is highly transparent, all size
groups of mahseers and schizothoracines are present in pools of
rivers such as Jhelum, Beas, Sutlej and Yamuna (Sehgal,1988). Water
temperature is always an important limiting factor influencing
geographical distribution and local occurrence within one water
system. Cold stenothermic species such as the endemic
schizothoracines (Schizothoraichthys esocinus
and Diptychus maculatus) and exotic brown trout have an upper
tolerance of about 20°C. Carps, mahseers and lesser barils
have awider tolerance and even survive water temperatures over
25°C. Schizothoracines and brown trout remain active in the near-

5. zero temperatures which prevail in streams of the Lesser and Greater
Himalaya during December and January. Hailstorms and drought
conditions in the Lesser Himalaya may cause adverse conditions,
leading to fish kill.To cope with the steep fall in temperature in
winter months schizothoracines migrate from headwaters to lower
altitude where they represent a sizeable part in fish catches in large
rivers and their tributaries. The rise in temperature in Kashmir
streams from near-freezing level to 10-17°C during May-June induces
S. richardsonii, S. longipinnis and S. curvifrons to spawn. In the Sutlej
River,S. richardsonii starts upstream migration with the rise in water
temperature during March. During the upstream migration the fish
still finds itself in waters of low temperatures,owing to the steady
inflow of snow-melt water. To avoid it the species migrates into
warmer side streams in which it spawns at temperatures of 17.5-
21.5°C, such as in the Ravi River, where its pawns in May. In the
upper Beas, the same species spawns only in July-August when the
water temperature is warm enough, but some fish of the same
species migrate downstream in the same river to spawn from
October to December at 19.0 to 22.5°C (Sehgal, 1999).The frequent
occurrence of spates in some rivers hinders spawning of cold water
fish. The low density populations of cold water fish in the upper
reaches of the Sutlej and Chenab rivers mayresult from the passage
of these rivers through deep and narrow gorges, and the presence of
cold glacier- and snow-melt water.As a result of a study of eleven
rivers in the north western Himalayas, Sehgal (1999) noted the
changes in the prevalent fish species (Table 3).The eastern Himalaya
drained by the Brahmaputra has a greater diversity of cold water fish
than the western Himalayan drainage. 218 fish species are listed for
the whole Himalayas (Menon,1962).The sub-family Schizothoracinae,
rich in genera and species, has mainly Central Asiatic distribution
although a few species are present also along the southern face of
the Himalayas(Seghal, 1999). This is perhaps on account of the Trans-
Himalayan origin of some of the major rivers like the Indus, the Sutlej

6. and the Brahmaputra, which made it possible to descend to the
lower reaches of these rivers.
Characteristics Greater siwalik
Zone
Himalayan Zone Lesser Himalayan
Zone
Elevation (m) Below 100 4000-2000 2000-1000
Substratum Pebbels & sand Rocks and boulders Boulders/stones with
Gravel etc
Water temp.(°C) 22.9 13.4 18.7
pH 8.0 7.4 7.9
Diss. O2 (mg/L) 7.9 9.3 8.7
Table : Characteristics of three Himalayan river zones
MEASURES FOR THE DEVELOPMENT OF COLD
WATER AQUACULTURE :-
For cold water aquaculture in the rivers and lakes long-term research
and planning are necessary. The following measures are suggested;
1. The natural environment of major watersheds of the rivers has
been greatly changed by deforestation, erosion and silting of river
beds. To restore the ecological balance of watersheds monitoring
and management must be practiced.
2. Regular ecological surveys should be made to monitor fish
population changes in pristine rivers as well as river courses altered
under the influence of man.
3. Habitat improvement is an essential factor for the
fishery improvement. To avoid seasonal changes of water level,

7. suitable pools should be created by constructing rock or boulder
dams. Such a habitat restoration practice will improve the fish
habitat quality and avoid the winter desiccation.
4. Water requirements for fish and river wildlife in the rivers of Nepal
should be determined by constant monitoring. The water quality and
volume should be well regulated to improve the habitat quality.
5. Areas downstream of dams are dewatered at many hydropower
projects. Therefore consideration should be given for water release
from the dam.
6. Biological considerations should be given to change traditional
pond design by incorporating spawning and incubation channels at
suitable places.
7. Fish ladders, fish lifts and fish guiding systems should be
developed along the dams to allow fish, river dolphins, crocodiles
and turtles to pass upstream and downstream.
8. Protective and catch-restrictive fishing regulations should be
based on periodic assessments of fish stocks and the critical stages in
fish life histories should be studied. Fishing law and bag limits,
restricting the use of nets below 2 cm mesh size, should been forced.
9. In the upland section of the rivers practice of electrofishing and
tossing of dynamite into water is in vogue. Such destructive activities
should be stopped.
10. In rivers the spawning and migration of fish usually take place in
June-September. These two months should be declared as closed
seasons by law.
11. To reduce the incidence of pollution in the rivers an adequate
provision should be made through legislation to check the pollution
caused by waste disposals from paper, beer and other factories.

8. 12. Snow trout populations are declining owing to high fishing
pressure in alpine waters. Therefore, it is highly desirable to establish
“snow trout sanctuary” at suitable places. The breeding of snow
trouts in a hatchery and releasing spawn or fry in rivers and streams
will help to stabilize the snow trout populations.
13. The deep-water pools of rivers and their feeder streams should
be declared mahseer sanctuaries. Such an establishment will help to
protect spawners.
14. Collection of fish fry from rivers, reservoirs and tail waters of
dams and spillage should be stopped. Such a commercial exploitation
will deplete the fish stock.
15. To preserve fish stocks of mahseer and the snow trout gene bank
a conservation programme should be developed.
16. Proper consideration should be given to develop environmentally
friendly aquaculture and uplift socio-economic conditions of
fishermen as well as fishermen education.
17. A nation-wide fish marketing network should be developed.
18. Introduction of exotics and transgenic species in native water
should be conducted only after pilot studies and so that they do not
disturb the ecosystem.
19. Enforcement of fishing laws and regulations should be
implemented.
20. A national aquarium should be constructed to popularize the
knowledge of fish and fisheries.