This document categorizes and describes different types of limnetic (inland water body) fisheries resources. It discusses lacustrine (lake) systems, including zonation patterns in lakes and thermal stratification. It also covers rivers, cold water bodies, wetlands including flood plains, and threats/conservation efforts. Key points include descriptions of eutrophic, oligotrophic, and mesotrophic lakes; types of wetlands like swamps, marshes, bogs, and fens; fish diversity in different systems; and impacts of habitat loss.

1. CATEGORISATION OF DIFFERENT
LIMNETIC FISHERIES RESOURCES
Presentation by:
V.Rishika
Jr mfsc
Dept of: AEM

2. WHAT IS LIMNETIC?
• Limnetic is generally the study of inland water
bodies.
• Different types of limnetic water bodies are:
 lacustrine
 rivers
 cold water bodies
 wetlands
 flood plain wetlands

3. WHAT IS LACUSTRINE?
• Lacustrine is a still water body or lentic water
body.
Eg:pond or lake
• A lake is a standing body of water completely
encapsulated by land.
• When a lake is large it is sometimes called as sea.
• Lake has no connection with ocean.
• Caspian sea is the world’s largest lake.
• Lake may be either freshwater or saltwater

4. ZONATION OF LAKE

5. 1.LITTORAL ZONE:
• Shallow water zone
• Light reaches the bottom
• Stimulates the growth of rooted plants
2.LIMNETIC ZONE:
• Open water area away from the shore.
• Most of the photosynthesis occurs in this zone.
• Light do not penetrate upto bottom.

6. 3.PROFUNDAL ZONE:
• This zone is present in deep lakes.
• Deep open water zone where there is low level of
photosynthesis.
• Characterised by compensation depth.
• Respiration=photosynthesis
• Low level of photosynthesis result in low DO.
4.BENTHIC ZONE:
• Bottom of the lake
• Organisms tend to tolerate cooler temperatures.
• Decomposition takes place.

7. THERMALSTRATIFICATION

8. EPILIMNION:
• Upper layer of circulating warm water
• Dissolved oxygen concentrations are moderate to
high.
THERMOCLINE/METALIMNION:
• Layer of rapid temperature and oxygen decrease
with depth.
• Separates upper and lower layer.
HYPOLIMNION:
• Cold deep water
• Non-circulating layer
• D.O is low or absent

9. CLASSIFICATIONOF LAKES BASEDON PRODUCTIVITY:
EUTROPHIC LAKES:
• Rich in plant nutrients
• Productivity is high
• High numbers of phytoplankton
• Contains high nitrogen and phosphorus

10. • Lake is shallow and contains weed beds.
• Contains accumulated organic sediments
• Fishing is good as it is a productive lake.
• Oxygen depletion occurs in lower layers

11. OLIGOTROPHIC LAKES:
• Low concentration of nutrients for plant growth.
• Low productivity
• Small population of phytoplankton ,zooplankton
bacteria and fish
• Poor fishing

12. • As the oligotrophic lake ages,it gradually
accumulates nutrients and sediments,and
move toward and eventually to eutrophic
stage.
• This natural eutrophication commonly takes
thousands of years.
MESOTROPHIC LAKES:
• Intermediate in most of the characteristics
between eutrophic and oligotrophic lakes.
• Moderate productivity.

13. DYSTROPHIC LAKES:
• Receives large amount of organic matter from
surrounding lands in the form of humic waste.
• This waste makes colour of water brown.
• Low in planktonic vegetation
• There is no productivity.

15. CLASSIFICATION BASED ON ORIGIN
Glacial lakes- eg .Alpine ( Argentina)
Rift valley lakes- eg. Baikal lake (Russia)
Depression lakes- lake victoria (Africa)
Volcanic lake –e.g lonar lake (india)
oxbow lake - Dal and wular lake in Jammu and
Kashmir

16. WHAT ARE WETLANDS
• It is a transition zone between truly aquatic
habitat and terrestrial habitat.
• Characterised as having water table.
• Provide habitat for variety of plants, animals.
• Wetlands covers 12% of he earth’s surface.
• February2 of every year is celebrated as
world wetland day recognising the
importance of wetlands and their
conservation.

17. ADVANTAGES:
• They are called as purifiers-kidneys of the land
scape.
• Prevents floods
• Protect shorelines
• Recharge aquifers with purified water
• Global climate stabilizers and
• Co2 absorbers.
• Plants in wetlands are used for heavy metals
accumulation.

19. TYPES OF WETLANDS
• Swamps
• Marshes
• Bogs
• Fens
• Swamps and bogs are being damaged by
natural disasters and human interactions.

20. SWAMPS:
• Swamp is a wetland that is forested.
• Characterised by mineral rich soil
• Inundated by flood water from rivers and
streams.

21. MARSHES
• Marshes dominated by grasses
• Settling of pollutants is effective when water
moves through marsh.
• Marsh vegetation and microorganisms use
excess nutrients which pollute the water.

22. BOGS
• Made by accumulation of peat material(dead
plant material).
• Bog is low fertile and decaying is slow
resulting in peat accumulation.
• Bogs Appear where the water at the ground
surface is acidic.
• Bogs are generally filled by rain water.
• Peat acts as a carbon sink
• Dried peat can be used as fuel
• Due to the removal of peat the bog wetland is
getting destroyed.

23. BOG

24. FENS:
• Fens have a diversity of plants which acts as
environmental indicators.
• Fens are similar to bogs in having peat
material
• Fens having acidic soils and low in minerals.

25. FISH DIVERSITY
• Striped -
Snakehead
• Clown knife fish
• Stripped Rasbora
• Spiny eel

29. WETLAND DESTRUCTION:
• In earlier days wetlands are considered as
“wastelands”.
• As a result they are drained and uses for other
purposes.
• Destruction of wetlands resulted in serious
consequences like increased flooding and
species extinction.

30. FLOOD PLAIN WETLANDS:
• A flood plain is an area of land adjacent to
stream or rivers.
• These are subjected to periodic or permanent
flooding from the adjacent rivers.
• They are also called as low lying lands.
3 categories:
• Riverine flooding:by rivers and channels
• Coastal flooding:by hurricanes and several
storms
• Shallow flooding:urban drainage

31. ADVANTAGES:
• Rich habitat for fish, plants and wild life.
• Water entering flood plains carries
pollutants,allows them to filter through the
soil.
• Protection against floods ,when water enters
from rivers
• Acts as aquifers in soil by groundwater
recharge
• As they are productive areas ,they can be used
for agriculture.

32. IMPACTS OF FLOOD PLAIN LOSS:
• Soil erosion
• Habitat loss
• Harms to biodiversity
• Eutrophication of lakes etc

33. RIVERS
• The India has a large net work of rivers.
• These are lotic water bodies .
• River system of the country has a total length
of about 29,000 km.
• Which include -14 major
- 44 minor.
• Divided in to –
• The Ganga river system
• The Brahmaputra
• The Indus
• The E-coast river system
• The w-coast river system

36. FISH DIVERSITY
 Mahaseers
 Ganga dolphin
 Catla catla
 Rohu
 Goldfish
 Silver carp
 Mrigal
 Catfish
 Snake heads
 Prawns etc

37. COLD WATER FISHERY RESOURCES
• Cold water resources comprise high and mid
altitude lakes,rivers and streams.
• Fishes having temperature tolerance limits
between 0-20℃ are called as cold water fishes.
• Optimum temperature range is 10-12℃
• Water maintains relatively low
temperature,which supports low production
levels.

38. • In India 258 species of cold water fishes
belonging to 21 family and 76 genera are
available.

41. MAJOR THREATS
• Introduction of exotic species
• over fishing activities
• Pollution
• industrial runoff
• habitat degradation and
• Predation etc.
CONSERVATION MEASURES:
• Ranching
• increase public awareness
• restoration / mitigation effort etc.

42. REFERENCES
• https://www.epa.gov
• https://www.worldwildlife.org
• https://www.sswm.info
• ca.water.usgs.gov/projects/2013-33.htm