Rivers, lakes, and reservoirs provide important ecosystem services but face threats to their sustainability. Climate change impacts water temperatures and precipitation patterns, affecting ecosystems. Pollution from contaminants, agriculture, and aquaculture introduces antimicrobial resistance and eutrophies water bodies. Invasive species outcompete native species through predation, habitat alteration, and transmitting diseases. Unsustainable aquaculture practices pollute waters and introduce non-native genetics through escaped fish. Overall, climate change and human activities degrade inland water quality and biodiversity.

1. Sustainable Management
Approach In Rivers, Lakes
And Reservoirs
Prepared by - Sourav Saha
M.F.Sc. 1st Year, FRM

2. Introduction
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Comparing to inland fisheries, marine fisheries are typically
international in scope, and concern much wider geographical
areas than inland fisheries.
In inland fisheries, conflict and management are more based on
bottom-up traditional local practices and the interests of local
groups.
Conflicts may include competition between commercial
fisheries and recreational fishers, or the competition between
fisheries and other uses of inland waters, such as the disposal
of wastewater, electricity production, agriculture, and leisure
activities.
In inland waters, overfishing problems are not as much of an
issue as they are in marine fisheries, but rather environmental
degradation represents the greatest challenge facing
sustainable development.

3. 
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Despite being a small component of the biosphere, most inland
rivers, lakes and reservoirs are exploited for diverse human activities.
They provide a wide range of ecosystem services, including flood
control, biodiversity, climate change mitigation, river flow regulation,
hydropower supply, as well as water purification and storage.
In recent decades, emerging global threats, such as biological
invasions, climate change, land use intensification, and water
depletion, have been driving forces of changes in lakes and
reservoirs.

4. Status Of Inland Water Bodies In
India
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Inland fisheries enjoys prime of place in Indian economy. It provides
employment and livelihood for fishers who solely depend on it.
The trend analysis of Indian fisheries sector reveals a paradigm
shift from marine dominated fisheries to a scenario where inland
fisheries has emerged as a major contributor to the overall fish
production in the country.
 Inland fisheries presently has a share of 75
percent in total fish production of the
country.

5. Inland fishery resources by states and union
territories

7. TOP 10 INLAND WATER CAPTURE
PRODUCERS

8. Differences between marine and inland
fisheries systems
Characteristics Marine fisheries Inland fisheries
Access Open Restricted
Structure Global scale Small scale, local systems
Predominant form of
fisheries
Commercial Recreational
Management system Reactive Proactive (manipulating)
Effects of equipments on
ecosystem
Extensive damage Less damage
Overfishing more less
Ecological diversity smaller great
Human impacts Long term influence Short term influence
Major concerns Overfishing, regulation of
fishing
Environmental
degradation

9. RIVERS OF THE WORLD
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It is in dynamic systems. Total length- 269000km.
Largest number in South America and least number
in Oceania.
Globally, the reservoir storage is attained about
seven times the standing of water in Rivers.
Important rivers of the world-
i. Nile-6650km
ii. Amazon-6400 km
iii. Yang tse-6300 km
Brahmaputra- 2897 km
Indus - 2897 km
Ganges - 2506 km

10. RIVERINE RESOURCES OF INDIA
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Much of the Ganga flows through Uttar Pradesh and form huge
delta in West Bengal
Bahmaputra flows through Assam
Indus flows through Jammu and Kashmir
Krishna through Maharastra
Mahanadi through Orissa
Brahmini through Orissa
Mahi through Gujarat
Sabarmati through Gujarat
Narmada through Madhya Pradesh
Tapti evenly through Madhya Pradesh, Maharashtra and Gujarat
Godavari through Andhra Pradesh and Maharashtra
Cauveri through Tamil Nadu and Karnataka
Subanarekha predominantly through Jharkhand

11. LAKES OF THE WORLD
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Lakes area contributes to about 1.7 million
km.
Lakes - North America stands first in area.
Large number of lakes in the temperate
zone of Europe and Asia, lakes are less
common in tropical Asia.
The Great Lake on the Tonle Sap in
Cambodia and Lake Tempe in Sulawesi
(Indonesia) are of the utmost importance to
fisheries.
Major lakes include Caspian Sea, Lake
Superior, and Lake Victoria, Baikal,
Tanganyika etc.

12. RESERVOIRS OF THE WORLD
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Manmade structures.
More than 60000 numbers of large reservoirs (>15 m dam height),
totally 4,00,000 km2 in water surface and about 6,500 km3 in
volume.
Area wise- Asia stands first followed by NorthAmerica.
Asia - 65% by number and 31% by volume
Lake Volta (8482 KM²) Ghana, Small wood reservoir (6527 KM²)
Canada and Kuybyshev reservoir (6450 KM²) Russia are important
largest reservoirs by surface area.
Lake kariba, Nasser, Guri, Williston are important largest
reservoirs by volume.

13. RESERVOIR RESOURCES OF INDIA
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Reservoir is the single largest inland fisheries resource in terms of
resource size and production potential.
The reservoirs are classified based on the water spread area and
water-holding capacity. The reservoirs are classified into large
(>5000 hectares), medium (1001 - 5000 hectare) and small reservoir
(<1000 hectare).
India has 19,134 small reservoirs with a total water surface area of
14,85,557 ha, 180 medium reservoirs with 5,27,541 ha, and 56 large
reservoirs with11,40,268 ha.
Small Reservoirs - TN
Medium Reservoirs - AP
Large Reservoirs - Karnataka
Largest Reservoir of India – Indira Sagar (MP)
First Reservoir of Independent India – Bhakra nangal
First Scientifically designed reservoir of India – Stanley reservoir

14. Open water fishery resources of India

15. Threats Affecting The Sustainability
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Climate Change
Contaminants
Exploitation
Introduced species
Fisheries enhancement and supplementation
Aquaculture
Climate Change

16. Climate Change
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Climate change is a major threat to the sustainable development of
lakes and reservoirs.
According to IPCC , the shifts in climate regimes associatedand
their changes in global precipitation, evapotranspiration, and runoff
patterns have caused alterations in flow and thermal regimes with
more severe and inevitable drought and flooding events.
Increasing temperature has had a significant impact on top
predators, such as pike (esox lucius), causing alterations in the
topological architecture of food webs and whole ecosystem
sensitivity to climate variation.
In temperate and boreal zones, the variation of precipitation can
change the nutrients import of freshwater bodies.

17. 
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Interestingly, these water bodies and climate change have a
double relationship.
On the one hand, the impact of climate change on global
temperature, sediment transport, temporal precipitation, and
the intensity of floods and droughts affect the sustainable
development of rivers, lakes and reservoirs.
On the other hand, they are themselves both natural and
artificial sources that can substantially contribute to climate
change via their degrading organic carbon storage, and
related carbon dioxide (CO2) and methane (CH4) emissions.

18. Contaminants In Ecosystem
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Another emerging threat for rivers and lake sustainability in future
decades is the ever-increasing number of emerging contaminants
as a result of the development of technologies adding more
products and chemicals into the environment.
These surreptitious contaminants are new compounds with little
environmental regulation and whose impacts are still not completely
clear.
They range from personal care products and illicit drugs to
endocrine disrupting compounds, which can pose a serious threat to
both the aquatic ecosystem and human health.
More importantly, the presence of micro plastics and antimicrobial
resistance in these waterbodies are increasing in developing
countries as a result of the widespread use of these products.
Agriculture, aquaculture and livelihood developments, caused a high
level of Antimicrobial resistance in surface water systems,
consequently, causing health problems to water users

19. EUTROPHICATION
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Eutrophication and heavy metals remain constant problems
in the stagnant waters due to the long impact of intensive
agricultural and industrial activities.
Some cases, excessive use of fertilizers added to the
aquaculture activities cause eutrophication in lakes and
reservoirs.

20. Invasive Species
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These freshwater bodies are considered among the most impacted
by species invasion, as invasions appear to be a principal contributor
to biodiversity loss in numerous systems.
In many instances fish have been introduced to satisfy local anglers
with strong preferences for exotic angling species of international
repute (e.g. salmonids and bass).
Fish have also been introduced deliberately for pest and disease
control (especially the mosquito fishes), as ornamental species for
aquariums and as a source of protein for human populations (e.g.
tilapias, carps).

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The major modes of impact associated with introduced fishes (both
exotic and translocated) are genetic effects via hybridisation,
alterations of habitat and water quality, consequences to native
populations of competition for space and food and from predation
and impaired health from imported parasites and diseases.
Cumulative invasions have disproportionately transformed the
communities living in these waterbodies in a way that non-native
species have dominated more than their terrestrial counterparts do.

23. Aquaculture
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Aquaculture is the farming of aquatic
organisms, usually confined in
facilities such as ponds or cages.
Where cultured organisms escape
into natural systems in significant
numbers, this may raise ecological
and genetic concerns.
Most aquaculture systems rely on
external inputs of feeds and/or
fertilizers and large-scale
aquaculture can be a significantm
source of nutrient pollution.

24. Fisheries enhancement and supplementation
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Aquaculture-based fisheries enhancement and supplementation
programs are frequently used in river and floodplain systems.
There are good examples where the stocking of hatchery fish has
contributed to the conservation or restoration of populations.
However, many aquaculture based enhancements have proved
ineffective and/or ecologically and genetically problematic.
Genetic risks to natural populations arise from low effective
population size of hatchery-reared fish (leading to inbreeding
depression) and from loss of local genetic distinctiveness and
adaptation if hatchery fish are not derived from local populations
(leading to outbreeding depression).

25. Exploitation
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In such multi-species fisheries, the relationship between
total effort and long-term total yield (obtained from a range
of different species) tends to be asymptotic, i.e. yield
increases initially with effort but approaches a constant
maximum over a wide range of higher effort levels.
As exploitation increases, large and slow-growing species
are depleted and replaced by smaller.
Recreational fisheries tend to have less drastic impacts than
food fisheries in that the target species are generally limited
and when these species are overexploited there are rarely
shifts to smaller elements of the community.

26. Management measures
Invasive species
control
Wildlife and
Fisheries
Management
Shore protection
Water Quality
Management
Nutrient Budget

27. Invasive Species Control
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Eradication , which is generally only possible when a new
introduction is detected already and the distribution and population
is low.
Containment to slow the spread and limit access to the waterbody
by screening off a portion of it.
Managing established populations to keep populations below a
threshold of ecological or economic effect.
Mitigating the impacts to particular activities or resources.
Monitoring the species to ensure chose management approaches
are effective.

28. Fisheries Management
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Maintain the target species at or above the levels necessary to
ensure their continued biological productivity.
Minimise the impacts of fishing on the physical environment and
on non target, associated and dependent species.
Maintain the stock at all times above 50% of its mean unexploited
level.
Use a suitable gear design
Unnecessarily don’t add fertilizers to the culture system. Because
it may lead to eutrophication in lakes and reservoirs.

29. Shore Protection
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The objective of lake shore line protection is to stabilize and protect these land
forms against scour and erosion from forces such as wave action, ice action,
seepage and runoff from upland areas.
Some of the methods includes,
Planting vegetation along the shoreline
Live staking – cuttings from woody shrubs thar are tamped directly to the
ground, and overtime, will root and grow on their own.
Fibre coir rolls
Encapsulated soil lifts
Stone and vegetation or vegetated rip rap

30. Water Quality Management
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Next to the lake surface water temperature, there are three important
parameters needs to be analysed in lakes and reservoirs.
The turbidity of the lakes describes the water clarity, or whether
sunlight can penetrate deeper parts of the lake. Turbidity often varies
seasonally, both with the discharge and growth of phytoplankton.
The trophic state index is an indicator of the productivity of a lake in
terms of phytoplankton, and indirectly reflects the eutrophication
status of a water body.
The lake surface reflectance describe the apparent colour of the
waterbody, intended for scientific users. The reflectance bands can
also be used to produce true colour images.

31. Nutrient Budget
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Lake nutrient budget account for sources and sink of nutrients as well as
nutrient cycling and sequestration.
Nutrient budgets quantify the external loadings, outflow rates, and lake nutrient
concentrations.
Nutrient dynamics in the lake and sources and sinks of nutrients in lakes help to
identify restoration approaches that are most likely to successfully reduce the
nutrient availability , phytoplankton blooms and other related problems.

32. MANAGEMENT MEASURES TO OVERCOME
HYDROLOGICAL MODIFICATIONS
 One of the solutions for habitat disconnection by the
construction of dams is the use of fish bypasses and fish
ladders.

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In a short-term period, dam removal can increase the
amount of sediment load leading to abrasion and toxicity to
biota and habitats.
However, it was also reported that the restoration of
unregulated flow regimes improved significantly the biotic
diversity due to the enrichment of free movement and
spawning grounds

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Attempts to mitigate, rather than remove, existing threats
are probably the most common approach to conservation of
river resources.
Only very limited mitigation effects can be carried out at
these aquatic ecosystems, such as liming of water bodies
affected by acid deposition, or management of regulated
rivers to compensate for hydrological effects of climate
change.
Other measures include creation of spawning substrate for
focal fish species (e.g. salmonids), instituting fish stocking
programs, providing simulated flood discharges and flushing
flows for particular ecological and water quality objectives.