Reservoirs in India hold potential for inland fisheries development but currently contribute less than expected to fish production. There are over 19,000 reservoirs in India covering 3.15 million hectares. The average fish yield from reservoirs is around 20 kg/ha but could be increased to 250 kg/ha through management. Key factors influencing reservoir productivity include morphometric characteristics, climate, soil properties, and chemical stratification. Management approaches for reservoirs focus on stock enhancement, species enhancement, and environmental enhancement through stocking of suitable fish species and regulating fishing efforts.

1. Reservoir Fisheries
Prepared by:
Satyaveer
Jr. M.F.Sc.

2.  Reservoirs are man-made lakes created by impounding river water for the purpose
of irrigation, power generation, flood control, and industrial water needs.
 A large number of river valley projects have been commissioned since independence
as a part of our development activities, resulting in a chain of such artificial
impoundments.
 These man-made lakes hold tremendous potential for inland fisheries development
in India has long been recognized.
 However, this vital resource is not contributing to the inland fish production of the
country to the extent it should.
 Unlike the rivers, which are under the increasing threat of environmental
degradation, the reservoirs offer ample scope for fish yield optimization through
adoption of suitable management norms.
Introduction

3. Cont.
 The biological potential of the various reservoirs was not evaluated to any reliable extent
until the 1970s, when fish yield from them stood at low level of 5 to 8 kg/ha/y.
 Organized research on reservoir fisheries was initiated in India only in the year 1971 with
the launching of an All India Coordinated Project on Reservoir Fisheries (AICPRF).
 The Project attempted to develop into all determinants of reservoir productivity,
including climatic, morphometric and edaphic variables and the dynamics of biotic
communities of the reservoir ecosystem in India.
 The limnology-mediated management norms evolved by the AICPRF have come to be
known as the ecosystem-oriented management (Natarajan, 1979).
 Application of these norms have resulted in a remarkable increase in fish yield in some of
the Indian reservoirs.
 The average fish yield in the country also registered an increase up to 15 kg/ha by the
mid 1980s. The present yield is estimated at 20 kg/ha.

4. Vallabh-sagar Reservoir
(Ukai, Gujarat)
Releasing fish seed in
Tungbhadra Reservoir (Karnataka)

5. Current Status of Reservoir in India
No. Resources Area
1 Total Area of Reservoirs 3.15 million ha
2 Total no. of Reservoirs 19,370
3 Area of Small Reservoir 1.48 million ha
4 Area of Medium Reservoir 0.52 million ha
5 Area of Large Reservoir 1.14 million ha
 Tamil Nadu has highest area of small reservoirs.
 Madhya Pradesh is top at total area of medium reservoirs.
 Karnataka has maximum no. of large reservoirs; area in Andhra Pradesh.

6. Classification of Reservoirs
Type Area Nos.
Small Reservoir < 1000 ha 19134
Medium Reservoir 1000 – 5000 ha 180
Large Reservoir > 5000 ha 56
Total 19370
 Water bodies less than 10 ha in area, being too small to be considered as lakes,
are excluded.
 The average productivity from these reservoirs in India is nearly 20 Kg/ha
against the production potential of 250 Kg/ha.
 Thus it indicates that resources are evidently under utilized.

7. Distribution of small, medium and large reservoirs in India
States
Small Medium Large Total
Number Area(ha) Number Area(ha) Number Area(ha) Number Area(ha)
Tamil Nadu 8895 315 941 9 19 577 2 23 222 8906 358 740
Karnataka 4 651 228 657 16 29 078 12 179 556 4 679 437 291
Madhya Pradesh 6 172 575 21 169 502 5 118 307 32 460 384
Andhra Pradesh 2 898 201 927 32 66 429 7 190 151 2 937 458 507
Maharashtra - 119 515 - 39 181 - 115 054 - 273 750
Gujarat 676 84 124 28 57 748 7 144 358 711 286 230
Bihar 112 12 461 5 12 523 8 71 711 125 96 695
Orissa 1 433 66 047 6 12 748 3 119 403 1 442 198 198
Kerala 21 7 975 8 15 500 1 6 160 30 29 635
Uttar Pradesh 40 218 651 22 44 993 4 71 196 66 334 840
Rajasthan 389 54 231 30 49 827 4 49 386 423 153 444
Himachal
Pradesh
1 200 - - 2 41 364 3 41 564
Northeast 4 2 239 2 5 835 - - 6 8 074
Haryana 4 282 - - - - 4 282
West Bengal 4 732 1 4 600 1 10 400 6 15 732
Total 19 134 1 485 557 180 527 541 56 1 140 268 19 370 3 153 366

8. Distribution of Small, Medium & Large Reservoirs in Karnataka
Category Number Area (ha)
Small 4651 228657
Medium 16 29078
Large 12 179556
Total 4679 437291
 1st in number of large Reservoirs.
 2nd in number of small Reservoirs.
 3rd in Overall area of Reservoirs.

9. Fish production systems
 Culture based Fisheries of small reservoirs and floodplain wetlands.
 Enhancement Fisheries of medium and large reservoirs.
 Capture Fisheries of rivers & estuaries.
 Culture Fisheries of ponds.

10. Fish production from reservoirs
⸗ The fish yield from reservoir is poor, varying from 0.05 kg/ha in Bihar to 35.5
kg/ha in Himachal Pradesh with national average of 20 kg/ha.
⸗ The av. national yield of small reservoir in India is 50 kg/ha.
⸗ The av. national yield of medium reservoirs is 12 kg/ha.
⸗ The av. national yield of large reservoirs is 11 kg/ha.

11. Fish production from other countries.
 China – 743 kg/ha
 Sri Lanka – 300 kg/ha
 Indonesia – 177 kg/ha
 Cuba – 100 kg/ha
 USSR – 88 kg/ha
 Thailand – 64.5 kg/ha

12. Fish production/potential from reservoir
Reservoir type Av. Production
Rate (kg/ha)
Total
Production
(tonnes)
If we increase,
Yield Rate
(kg/ha)
Expected
Production
(Tonnes)
Small 49.50 74,129 100 148,556
Medium 12.30 6,488 75 39,565
Large 11.43 13,033 50 57,013
Total 93,650 2,45,134

13. Lakes V/s Reservoirs
No. Lakes Reservoirs
1 Natural water bodies having circular
water basins
Man-made water impoundments having
elongated and dendritic water basins
2 Water level fluctuation generally
small
Water level fluctuation is more
3 Water inflow from different small
tributaries
Water inflow from one or more large
rivers
4 Rate of Sediment deposition is slow
under natural processes
Rate of Sediment deposition is rapid
5 Slow ecosystem succession Ecosystem succession is often rapid
6 Having stable flora & fauna Variable flora and fauna

15. Trophic changes in Reservoirs
₡ Initial high fertility.
Last for 2-3 years
₡ Trophic depression.
Rapid utilization of nutrients + sedimentation
₡ Final fertility.
Stabilization near half the magnitude of initial phase.
₡ Indian reservoirs have final fertility much higher than initial.

16. Common Fish Species of Reservoirs of India
Group Species
IMC Labeo rohita, L. calbasu, L. fimbriatus, Catla catla, Cirrhinus
mrigala.
Mahseers Tor tor, T. putitora, T. khudree, Neolissochilus hexagononlepis.
Minor carps Cirrhinus cirrhosa, Labeo kontius, L. bata, Puntius sarana, P.
dubius, P. carnaticus.
Large Catfishes Spearota aor, S. seenghala, Wallago attu, Pangasius pangasius.
Feather-backs Notopterus notopterus, Chitala chitala.
Air breathing cat fishes Heteropneustes fossils, Clarias batrachus.
Murrels Channa marulius, C. striatus, C. punctatus.
Uneconomic fishes Ambassis nama, Puntius sophore, Osteobrama cotio, etc.
Exotic fishes Oerochromis mossambicus, Hypophthalmichthys molitrix,
Cyprinus carpio, Grass carp, etc.

17. Factors influencing the biological productivity in
Reservoirs
╘ Morphometric factors
╘ Climatic factors
╘ Edaphic factors
╘ Chemical Stratification

18.  Morphometric factors
╕ Depth is the most important to be correlated with productivity because shallow
reservoirs have larger proportion of substrate in euphotic zone as compared to
deeper reservoirs where most of the substrate is locked up in aphotic zone.
╕ Shore development is another useful index in determining productivity denoting
degree of irregularity in shoreline.
╕ Fluctuations in water level: A stable reservoir level is more conducive to growth
of organisms. Sudden fluctuations in water level is harmful because plankton
pulse coincide with period of least level fluctuations, and all biotic communities
are in their lowest ebb during maximum level fluctuations.

19.  Climatic factors
⁞ The most important climatic factor is latitudinal location of reservoir, which
determines quantum of solar energy available for photosynthetic activities.
⁞ The latitude also determines the air temperature that plays important role in
thermal and nutrient regimes of reservoirs.
⁞ Thermal stratification is limnologically important because in thermally stratified
lakes, water above (epilimnion) and below thermocline (hypolimnion) does not
mix up and thereby rich nutrients gets locked up at the bottom.
⁞ Wind is another important meteorological factor that helps mixing of water,
facilitating nutrient transport.
⁞ The rainfall at catchment area is also very important than rainfall at reservoir site.

20.  Edaphic factors
• The physico-chemical characteristics of water and soil are major determinants
of biogenic productivity of reservoir.
• Water transparency is one such physical variable significant to production. The
poor light penetration may be due to planktonic bloom is a positive index of
production.
• Dissolved oxygen - main source of dissolved O2 in water is absorption from air
and through photosynthesis.
• pH slightly above alkaline and not above 8.5 is considered conducive to
productivity. A total alkalinity over 50 ppm and hardness above 70 ppm are
indicator of better productivity.
• Morpho-edaphic index used to estimate the potential of the reservoir.
• Morpho-edaphic index = total dissolved solids (mg/l) / mean depth (m).

21.  Chemical Stratification
o Vertical distribution of chemical constituents of water.
o Trophogenic layer – high rate of photosynthesis, high oxygen.
o Tropholytic layer – Low DO, Putrification of organic matter.
o Oxycline – decline in oxygen
Klinograde curve Orthograde curve
Co2 in Epilimnion , O2 O2 value more or less uniform
Co2 in Hypolimnion , O2
o Klinograde curve is considered as productive character.

22. Trophic dynamics ( 90 % loss of energy)
Producers Autotrophs Primary producers Phytoplankton
Consumers Heterotrophs Primary consumers
Secondary Consumers
Tertiary consumers
Grazers/browsers
(zooplankton, fishes)
Fishes (carnivores).
Large predators, top
carnivores
Decomposers Saprophytes Mineralizing organic
matter & recycling.
Bacteria / fungi

24.  Energy flow
… Photosynthetic efficiency:
… Efficiency with which solar energy is converted to chemical
energy by producers.
… Ecological efficiency:
… Efficiency with which the above energy is utilized by consumers.

25. Ecosystem Approach to Management
› Productivity depends on biogenic capacity to transform solar energy into
chemical energy.
› Energy fixed at primary producer level passes through trophic chain and fraction
ends up as fish flesh.
› The structure of different food biotic communities ( trophic dynamics) assumes
great significance to reservoir fishery management.
› Shortening food-chain will lead to high rate of fish production.
› Little scope for changing community structure of plankton to increase primary
productivity.
› Alterations in species spectrum can be done with stocking of suitable fish
species.

26. Management of medium/large reservoir - Enhancement fisheries
› Management practices intermediate to culture & capture fisheries.
› Stock enhancement
› Species enhancement
› Environmental enhancement
› Management enhancement
› Enhancement using natural production basis
› Mesh size and gear restrictions are among the most easily applied management
regulations.
› Mesh size restriction involves regulation of the exploitation rate or the exploitation
pattern.
› These regulations result in utilizing maximum productivity of ecosystems.

27. Cont.
› Stock enhancement: Stocking of fishes, Conservation of habitat, regulation of
fishing effort & mesh-size regulation
› Temporary measure for correcting imbalances in species spectrum.
› To compensate for recruitment failure.
› Stocking successful only when stocked fishes breed and propagate
themselves.
› Stocking is only tool for improving stock productivity with uncertain chances
of success.

29. › Species enhancement: Stocking of suitable fish species.
› To have diversification in fish population.
› To utilize all niches of biotope.
› To harvest maximum sustainable crop.
› Environmental enhancement: Artificial eutrophication – addition of
fertilizers after careful examination of the possible impact on the environment.
- China use this instrument in big way.
› Management enhancement: Species selection, stocking rate, size at stocking,
size at harvesting, growing time, etc.
Cont.

30. Selection of species
• Principles to be followed:
 The fish should succeed growth &
reproduction in the given
environment.
 Faster growth rate & high FCR.
 Herbivore with short – food chain.
 Resistance to diseases.
 Availability of seed & minimum cost.
 Stocking & managing should be
economical.
Stocking rate
o Advanced fingerling of carps
( 10 -15 cm)
o Stocked at 250 nos. / ha in large
reservoirs free from catfishes.
o Stocked at 500 nos. / ha in catfish
dominated reservoirs.

31. Removal of catfish / weed
fishes
 Weed & cat – fishes creates
competition with major carps.
 Drag nets (shore seines) are
effective for eradication.
 It can be done in summer month
during low water level.
 It is better to stock reservoir
immediately after its creation
before catfish or weed-fishes get
hold on it.
Knowledge of biology of
fish
oBreeding biology: Stocking of
large/medium reservoir is imp.
but its success depends upon
recruitment of fishes
oFood & feeding habits:
Availability/abundance of
natural food available.
oPhysiology: Growth rate.
oFecundity: Number of eggs.

32. Crafts & Gears
□ Plank-built, flat bottomed boat (2-3 m in
length) are used in most of the reservoirs of
North India.
□ Coracle (a saucer-shaped country craft) is
major fishing craft in South India.
□ Fishing done mostly by surface gill-nets (mesh
size: 20 – 150 mm) – size 50x2 m.
□ Drag-net used for removal of cat & weed
fishes.
□ In South India, the drag net is known an ‘alivi’
while in North India it is known as “Mahajal”.

33. Constraints of reservoir fisheries
► Pollution
► Siltation
► Soil erosion

34. Recommendations for reservoir fisheries management
◘ Seed requirement & Stocking
◘ Escapement of fish
◘ Fish farms
◘ Pen & cage culture.
◘ Conservation
◘ Mesh size regulation
◘ Fish marketing
◘ Co-operative societies
◘ Multiplicity of ownership
◘ Fishing systems
◘ Integration
◘ Research

36. Stanley reservoir (Mettur dam, TN)
• First scientifically developed reservoir.
• Constructed on River Cauvery (Palar, Chennar
and Thoppar) at Mettur in 1934.
• Total length of the dam is 1700 meters
• Fish production was 660 tons/year with
dominance of IMC.
• 1991-92 production was 110/tons/year.
• Lost its glory due to lapses on management.
• Stocking of L. fimbriatus, P. carnaticus,
common carp wasteful.

37. Sathanur reservoir (TN)
• It is also known as Catla reservoir with
dominance of Catla after its planting in 1957.
• Also known as crown of jewel due to high
revenue generation.
• Total yield of Catla is 91 %.
• Unintentional stocking of Tilapia, R. corsula,
C. cirrhosa, L. kontius, L. fimbriatus didn’t
affect Catla.
• Wallago attu is the dominant predator, which
maintained the satble population in the
reservoir & forms 8% of the fish caught.

38. Nagarjuna Sagar (AP)
• World's largest masonry dam built across Krishna
River.
• A complete list of 38 species of fish recorded.
• In AP, Godavary & Krishna rivers have Catla, but
the reservoir of the state are not yielding to that
extent.
• Stocking of this reservoir was regular but the rate
was poor due to which IMC has little impact.
• Catfishes dominate over carps
• Recommendation: Stocking of fingerlings of IMC,
Common carp, M. malcolmsonii, etc should be
done.

39. Tungabhadra Reservoir (Karnataka)
• Constructed along Tungabhadra river
(tributary of Krishna River) in Munirabad,
Koppal district.
• Tungabhadra: Two streams viz., Tunga
(147 km) long & Bhadra (178 km) long which
rise in the Western Ghats.
• It runs for 382 km (237 miles) in Karnataka &
forms the boundary between K’taka and AP.
• Production to the tune of 91 kg/ha (1986-87)
• 95 % fish catch is weed fishes.
• Major carp could not come up in the reservoir
due to low stocking density, breeding failure,
etc.

40. Gandhisagar reservoir ( MP)
• The reservoir was devoid of Catla in
pre-impoundment period but after
stocking, there has been breeding,
recruitment and high yield of Catla
around 60-70%.

41. Gobindsagar reservoir ( HP)
• The reservoir is on the river Sutlej and is
named in honor of Guru Gobind Singh.
• One of the world's highest gravity dams.
• It is on northern latitude with low temp.
• Yield 113 kg/ha due to good management
practices.
• After accidental entry of Silver carp in
1971, silver carp dominates with 71 %,
eliminating IMC & other carps with
Mahseer.

42. Vallabh Sagar reservoir (Ukai, Gujarat)
• Constructed across the Tapti River, is the second largest reservoir in
Gujarat after the Sardar Sarovar.
• Catchment area = 62,255 km2 & Water-spread area = 52,000 hectares.
• Productive large reservoir- 160 kg/ha (1997-98).
• The catches of major carps are declining but that of cat-fishes are
increasing.
• The reservoir is unique in having an endemic Hilsa population
contributing 2.3 %.

43. Gobind Ballabh Pant Sagar (Rihand, UP)
• The reservoir dominated by catla (73-99 %) from
1971-72 to 1980-81.
• Was popularly known as Catla mine.
• Catla fish got adjusted to the ecosystem so well that it
was reflected as the most outstanding monospecies
fishery of the reservoir.
• The Fishery declined due to thermal pollution &
lapses on management.
• Gears commonly used are surface gill net and giant
dragnet.

44. Thank You