Better management techniques for rural fish farms

1. చెరువు నుండి నీటి కలుపు తొలగుంపు, వేటాడే మరియు
కలుపు చేపల తొలగుంపు, సస్టై నబుల్ ఆక్వాకలచర్
నిర్ాహణ పద్ధ తులు
Removal of Aquatic weeds, Eradication of
Predatory, weed fishes from ponds and
Sustainable Aquaculture Management practices
By;
B. Bhaskar
FFO&PC, Mahabubabad

2. Classification of Weeds
• Classification of Weeds
• 1. Floating weeds : Eichornia, Pistia, Azolla,
Lenpa, etc.
• 2. Marginal weeds : Colecasia, Typha, Cyperus,
Marsilia, etc.
• 3. Emergent weeds : Nymphae, Myriophyllum,
Nelumbo, etc.
• 4. Submerged weeds: Hydrilla, Valisnaria, Chara,,
Ceretophyllum, etc.
• 5. Algal weeds : Spirogyra, Microcystis,
Oscillatoria, Dinoflagellates, etc.,

3. Aquatic weeds

4. Name aquatic plants
• Water lettuce
• Sacred Lotus
• Prickly Water Lily
• White Water-Lily
• Victoria amazonica
• Egyptian lotus
• Nuphar japonica
• Common water hyacinth
• Hydrilla
• Arums
• Cattail
• Water lettuce

5. Aquatic weeds

7. Biological weed controlling methods
• The method is more advantageous since the undesirable weeds are converted into fish flesh.
• It is cheap as no labour is involved and most suitable from the social and environmental point of view.
• The method employs certain organisms which feed on the weeds.
• The grass carp which can eat up much more aquatic vegetation is itself an excellent example of biological weed
control.
• The common carp helps in uprooting of certain plants.
• Tawes, Puntius gonionotus is also a good feeder of aquatic weeds.
• The Yamuna turtle consumes water hyacinth in the ponds.
• Common weed eating fish and the weeds of their preference
• Fishes
• Names
• Feed upon
• Grass carp
• Ctenopharyngodon idella
• Submerged weeds e.g: Hydrilla, Najas , Ceratophyllum, Potamogeton, Otteliaand duck weeds
• Common carp
• Cyprinus carpio
• Tender shoots
• Gaurami
• Osphronemus goramy
• Tender shoots of submerged weeds and filamentous algae
• Pearl spot
• Etroplus suratensis
• Filamentous algae
• Silver carp
• Hypophthalmichthys molitrix
• Algal bloom

8. Predatory Fishes
• Predatory Fishes
• Fishes which predate the spawn, fry and fingerling of
cultured fishes.
• They get into cultured ponds through water or seeds.
• They breed easily in confined water little earlier than
carps and therefore their size will be bigger than the
size of the carps.
• They compete for food, space and DO and result in
poor growth of carps.
• Their complete eradication using physical methods is
difficult.
• They have the habit of burrowing in the mud bottom.
• Use of pesticides is inevitable.

9. Common predatory fishes are:
• Common predatory fishes are:
• Channa spp., Clarias batraches, Heteropneustes fossailis,
Pangsius, Mystus sp. Ompok spp., Wallage
attu and Glossogobius giuris etc.
• Weed Fishes
• These are uneconomical, small sized, naturally occuring or
introduced accidentally in ponds along with fish seeds.
• They compete for food, space and dissolved oxygen.
• They have high fecundity and breed well before major carps
breed.
• Many of them breed throughout the year.
• Therefore, fish seeds from wild contain seeds of weed fishes.
• Common weed fishes are:
• Puntius sp., Oxygaster sp., Ambassis sp., Amblypharyngodon
mala. Colisa sp., Rasbora sp., Aplocheilus sp., Laubuca sp.,
Esomus danricus, etc.

11. Removal of predatory and weed fishes:
• 1. Repeated netting:
• Repeated netting is suitable for only those ponds
having no other fishes except carps.
• It is not possible catch predatory and weed fishes
simply by netting.
• Remaining fishes will breed and have sizable
population in the pond.
• 2. Dewatering the pond is the best method.
• Dewater the pond, catch all the fish and allow the
pond bottom to dry till the bottom soil cracks.
• Summer is the best time for this.
• 3. Poisoning the pond in case dewatering and drying
is not possible.

12. Recommended doses of fish poisons
• Recommended doses of fish poisons
• Poison
• Dose (kg/ha/m)
• Bleaching powder
• 350 – 500
• Mohua oil cake
• 2500
• Anhydrous ammonia
• 20 – 30
• Powdered seed of Croton tiqlium
• 30 – 50
• Root powder of Milletia pachycarpa
• 40 – 50
• Seed powder of Milletia piecidia
• 40 – 50
• Seed powder of Barringtonia acutangula
• 150
• Seed meal of tamarind (Tamarindus indica)
• 1750 – 2000
• Tea seed cake (Camellia sinensis)
• 750

13. Promotion in fish Harvesting and facilities:&
regulations:
• Promotion in fish Harvesting and facilities:& regulations:
• 1) drag nets
• 2) Crafts and nets
• 3) life jackets
• 4) training on multiple fishing nets fabrication, mending, crafts
• 5) promotion of sustainable traditional harvesting gears and crafts.
• 6) practicing of seasonal banning/closed seasons.
• 7) prevention of use destructive fish harvesting gears, crafts and illegal unreported
and unregulated fish harvesting actives.
• 8) mesh size regulations
• 9) minimum legal fish harvest size regulations.
• 10) prohibit poisoning of open water body.
• 11) endangered fish banning during breeding season.& critical larval life stage.
• 12). Minimum legal size harvest rule.
• 13) polluters pay principle.
• 14) random impact assessment study of open water bodies. In order maintain
ecological sustainable best fishing and aquaculture practice..
• 15) Maintain the quality of catch for fetching high market value from harvest
until reaches consumer via cold chain & other preservation practices.