LIMNOLOGICAL CHARACTERISTICS AND LIMNOLOGICAL CHARACTERISTICS AND CAGE CULTURE PRACTICE IN CAGE CULTURE PRACTICE IN INDRASAROBAR RESERVOIR OF NEPAL INDRASAROBAR RESERVOIR OF NEPAL Madhav K. Shrestha (IAAS, Chitwan, Nepal) Narayan P. Pandit (FDC, Hetauda, Nepal) World Aquaculture Conference 2008, 19-23 May, Busan, South Korea
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LIMNOLOGICAL CHARACTERISTICS AND CAGE CULTURE PRACTICE IN INDRASAROBAR RESERVOIR OF NEPAL
LIMNOLOGICAL CHARACTERISTICS AND CAGE CULTURE PRACTICE IN INDRASAROBAR RESERVOIR OF NEPAL. Madhav K. Shrestha (IAAS, Chitwan, Nepal) Narayan P. Pandit (FDC, Hetauda, Nepal). World Aquaculture Conference 2008, 19-23 May, Busan, South Korea. ACKNOWLEDGEMENTS. - PowerPoint PPT Presentation
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LIMNOLOGICAL CHARACTERISTICS AND LIMNOLOGICAL CHARACTERISTICS AND CAGE CULTURE PRACTICE IN CAGE CULTURE PRACTICE IN
INDRASAROBAR RESERVOIR OF NEPALINDRASAROBAR RESERVOIR OF NEPAL
Madhav K. Shrestha (IAAS, Chitwan, Nepal)Narayan P. Pandit (FDC, Hetauda, Nepal)
World Aquaculture Conference 2008, 19-23 May, Busan, South Korea
AquaFish CRSPAquaFish CRSPUSAIDUSAID
The Aquaculture CRSP is funded in part by United States Agency for International
Development (USAID) Grant No. EPP-A-00-06-00012-00.The opinions expressed herein are those of the authors and do not
necessarily reflect the views of the US Agency for International Development.
ACKNOWLEDGEMENTS
This research was funded by National Agricultural Research and Development Fund (NARDF), Nepal.
All the funding for attending WAS ’08 was made by AquaFish CRSP.
IntroductionIntroduction
• Indrasarobar reservoir Indrasarobar reservoir was built by damming was built by damming in small river valley of in small river valley of mountain region of mountain region of central Nepal.central Nepal.
• Established in 1982 for Established in 1982 for hydropower generation.hydropower generation.
• Lies at the altitude of Lies at the altitude of 1430 m from mean sea 1430 m from mean sea level (msl) at bottom.level (msl) at bottom.
• When filled it reaches When filled it reaches 1530 m msl.1530 m msl.
• Reservoir is 7 km in Reservoir is 7 km in length and 50-500 m in length and 50-500 m in width.width.
• Total area is 216 ha Total area is 216 ha when filled and 55 ha when filled and 55 ha when dry.when dry.
Introduction….Introduction….
• Water depth lowest 60 Water depth lowest 60 m and highest 100 m .m and highest 100 m .
• Reservoir is fed with Reservoir is fed with seven small streams. seven small streams.
• Filled during rainy Filled during rainy season and draw down season and draw down continuously till next continuously till next rainy season occurs.rainy season occurs.
Introduction….Introduction….
• Started in 1988Started in 1988
• Technology copied Technology copied from Phewa lake from Phewa lake (Extensive system)(Extensive system)
Monthly mean total nitrogen (TN) and total Monthly mean total nitrogen (TN) and total phosphorus (TP) trend in reservoir during 2006-phosphorus (TP) trend in reservoir during 2006-20072007
0.0
0.5
1.0
1.5
2.0
2.5
20-M
ay
19-J
un
19-J
ul
18-A
ug
17-S
ep
17-O
ct
16-N
ov
16-D
ec
15-J
an
14-F
eb
16-M
ar
15-A
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Date
Nut
rient
con
tent
(m
g/L)
TN TP
Monthly mean total ammonium nitrogen (TAN) and Monthly mean total ammonium nitrogen (TAN) and soluble reactive phosphorus (SRP) content trend in soluble reactive phosphorus (SRP) content trend in reservoir during 2006-2007.reservoir during 2006-2007.
0.00
0.02
0.04
0.06
0.08
0.100.12
0.14
0.16
0.18
0.20
20-M
ay
19-J
un
19-J
ul
18-A
ug
17-S
ep
17-O
ct
16-N
ov
16-D
ec
15-J
an
14-F
eb
16-M
ar
15-A
pr
Date
Nut
rient
con
tent
(m
g/L)
TAN SRP
ConclusionConclusion
• Increased cage landing has decreased Increased cage landing has decreased productivity – Plankton limitationproductivity – Plankton limitation
• Mean fish harvest size has been Mean fish harvest size has been decreaseddecreased
• Current cage culture is about 4 ha Current cage culture is about 4 ha which is about 2% area of the reservoir which is about 2% area of the reservoir when fully filled and about 7% of the when fully filled and about 7% of the reservoir when lowest water level.reservoir when lowest water level.
RecommendationRecommendation
OptionsOptions
• Decrease cage culture areaDecrease cage culture area
• Decrease stocking densityDecrease stocking density
• Introduce feeding system which will support non Introduce feeding system which will support non feeding cage culture system too.feeding cage culture system too.
Currently Government has chosen recommendation Currently Government has chosen recommendation # 2 and has asked cage culture farmer to reduce # 2 and has asked cage culture farmer to reduce stocking density by 50% (10 to 5/mstocking density by 50% (10 to 5/m33))