669
D. Kar, Wetlands and Lakes of the World,
DOI 10.1007/978-81-322-1023-8_32, © Springer India 2013
Fishes are primarily adapted cold-blooded
aquatic vertebrates with paired and unpaired fi ns
for locomotion and gills for respiration. Fish
serves as an item of staple food of man in many
regions of the world. Freshwater Fishery
Management ( FWFM ) may be defi ned as the
manipulation of freshwater habitats and fi sh
population to maintain the habitat and to increase
fi sh yield for commercial and recreational uses .
The fi shery managers generally apply a variety of
techniques in order to maintain, improve and
increase fi sh population. Some of the aspects of
FWFM are discussed below.
32.1 Habitat Improvement
Fishery habitats may be altered to increase the
competitive advantage for desirable species (Kar
and Dey 1987 ). Also, the total carrying capacity
of the habitat may be improved for the production of fi sh biomass. Owen ( 1985 ) had noted that
one positive habitat manipulation often leads to
other positive effects .
Habitat improvement may be done by the
following means.
32.1.1 Alteration of the Land
This may include stabilisation of the shoreline of
the habitat, improvement of covers for fi sh and
creation of artifi cial spawning sites (Cooper 1980 ).
32.1.2 Alteration of the Water
It may be done by controlling turbidity (Dey and
Kar 1987 ), aeration and fertility . Such practices
may change the vegetation pattern (Dey and Kar
1994 ), control spawning and affect predation
(Noble 1980 ).
Enhancing the oxygen level of the water is a
technique often used by fi shery managers.
Typically, the warm water fi shes require oxygen
level of about 3 mg/l. During winter, snow may
form a blanket of frozen lake in the cold region,
thereby may reduce photosynthetic oxygen
production. To eliminate this problem, fi shery
managers could increase oxygen production by
various techniques.
Fishery managers could also alter the fertility
of water by increasing phytoplankton production
or by directly adding organic manure .
32.1.3 Alteration of Vegetation
Freshwater habitat may be improved by controlling the associated aquatic vegetation (Dey and
Kar 1989a ). The excessive vegetation may be
detrimental to fi shery with regard to the fact that
it may upset the predator – prey relationship.
Further, overlying thick vegetation deprives the
phytoplankton of the needed nutrients, and eventual decomposition of the same vegetation may
result in decrease in the level of dissolved oxygen . The aquatic macrophytes may be controlled
32
Fisheries Scope in the Wetlands
and Enhancement Methods
D. Kar, Wetlands and Lakes of the World,
DOI 10.1007/978-81-322-1023-8_32, © Springer India 2013
Fishes are primarily adapted cold-blooded
aquatic vertebrates with paired and unpaired fi ns
for locomotion and gills for respiration. Fish
serves as an item of staple food of man in many
regions of the world. Freshwater Fishery
Management ( FWFM ) may be defi ned as the
manipulation of freshwater habitats and fi sh
population to maintain the habitat and to increase
fi sh yield for commercial and recreational uses .
The fi shery managers generally apply a variety of
techniques in order to maintain, improve and
increase fi sh population. Some of the aspects of
FWFM are discussed below.
32.1 Habitat Improvement
Fishery habitats may be altered to increase the
competitive advantage for desirable species (Kar
and Dey 1987 ). Also, the total carrying capacity
of the habitat may be improved for the production of fi sh biomass. Owen ( 1985 ) had noted that
one positive habitat manipulation often leads to
other positive effects .
Habitat improvement may be done by the
following means.
32.1.1 Alteration of the Land
This may include stabilisation of the shoreline of
the habitat, improvement of covers for fi sh and
creation of artifi cial spawning sites (Cooper 1980 ).
32.1.2 Alteration of the Water
It may be done by controlling turbidity (Dey and
Kar 1987 ), aeration and fertility . Such practices
may change the vegetation pattern (Dey and Kar
1994 ), control spawning and affect predation
(Noble 1980 ).
Enhancing the oxygen level of the water is a
technique often used by fi shery managers.
Typically, the warm water fi shes require oxygen
level of about 3 mg/l. During winter, snow may
form a blanket of frozen lake in the cold region,
thereby may reduce photosynthetic oxygen
production. To eliminate this problem, fi shery
managers could increase oxygen production by
various techniques.
Fishery managers could also alter the fertility
of water by increasing phytoplankton production
or by directly adding organic manure .
32.1.3 Alteration of Vegetation
Freshwater habitat may be improved by controlling the associated aquatic vegetation (Dey and
Kar 1989a ). The excessive vegetation may be
detrimental to fi shery with regard to the fact that
it may upset the predator – prey relationship.
Further, overlying thick vegetation deprives the
phytoplankton of the needed nutrients, and eventual decomposition of the same vegetation may
result in decrease in the level of dissolved oxygen . The aquatic macrophytes may be controlled
32
Fisheries Scope in the Wetlands
and Enhancement Methods