VI
TABLE OF CONTENTS
Page
TITLE PAGE 1
DECLARATION 11
ABSTRACT 111
ACKNOWLEDGMENTS V
TABLEOFCONTENTS VI
LIST OF TABLES IX
LIST OF FIGURES XI
LIST OF PLATES X I11
CHAPTER 1 General Introduction 1
l.Importance of fish as a source of animal protein to
people of developing countries, especially that of
rural sector.................................................................... 1
2.The two major sources of fish - marine and
freshwater (including aquaculture)................................... 2
3.Sri Lankan situation and why freshwater fishes are
important............................................................................ 3
4. Freshwater fishery resources........................................... 8
5. Species used for culture fishery and pond
aquaculture......................................................................... 9
6. Importance of seed sources............................................. 11
7. Why development of community based seed sources
are important for Sri Lanka............................................... 12
8. Aim of the study.............................................................. 13
CHAPTER 2 Materials and Methods-General 14
Description and arrangement of experimental tanks.... 16
Preparation of tanks........................................................ 16
Measurement of physico-chemical parameters............. 20
Sampling and length/weight measurements.................. 20
Analyses of data............................................................. 21
Method of feeding of post-larvae and fry..................... 21
Plankton studies.............................................................. 23
CHAPTER 3 Effect of organic manure on growth and survival
of larvae of bighead carp, Aristichthys nobilis 26
Introduction..................................................................... 26
Materials and Method..................................................... 28
Results.............................................................................. 29
Discussion....................................................................... 35
CHAPTER 4 Effect of stocking density on the growth and
survival of fry of common carp (Cyprinus carpio) 39
Introduction..................................................................... 39
Materials and Method..................................................... 39
Results.............................................................................. 40
Discussion....................................................................... 45
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CHAPTER 5 Effect of stocking density on the growth and
survival of post-larvae of Aristichthys nobilis,
Ctenopharyngodon idella, yprinus carpio and
Labeo rohita 4 6
Introduction..................................................................... 46
Materials and Method.................................................... 47
Results (a) Bighead carp and grass carp......................... 48
(b)Rohu and common carp.............................. 50
Discussion....................................................................... 54
CHAPTER 6 Effect of the supplementary feed on the growth
and survival of post-larvae of common carp and
rohu reared in cement tanks 5 8
Introduction..................................................................... 58
Materials and Methods................................................. 60
Results.............................................................................. 61
Discussion....................................................................... 66
CHAPTER 7 Effect of cowdung on natural food production for
the rearing of post-larvae 70
Introduction..................................................................... 70
Materials and Methods.................................................. 72
Results............................................................................ 72
Discussion....................................................................... 79
CHAPTER 8 General Discussion........................................................ 83
REFERENCES 110
APPENDICES Appendix I ........................................... ............................. 126
IX
List of Tables Page
Table 1.1 The extent and the fish species to be stocked in
various water bodies....................................................... 04
Table 1.2 Aquaculture and Inland fish production target
(MT)................................................................................. 06
Table 1.3 Fish introductions into Sri Lanka (from De
Silva, 1988......................................................................... 10
Table 2.1 Experiments that were carried out in Udawalawe and
Ginigathena Fisheries Stations......................................... 15
Table 2.2 Preparation of tanks for stocking post-larvae (PL)... 19
Table 2.3 Method of feeding of post-larvae and fry in this trials 21
Table 2.4 The proximate composition(%) of fish feeds used.... 22
Table 3.1 Final(after 34 days) mean length, Specific growth and
percentage survival of bighead carp PL reared under
different treatments........................................................ 29
Table 3.2 Temperature (Morning & Evening), dissolved
oxygen concentration (DO) and pH in PL rearing
tanks under different manure treatment....................... 31
Table 3.3 Secchi disc depth, volume of zooplankton and
volumeof phytoplankton in PL rearing tanks under
different manure treatments............................................. 31
Table 4.1 Physico-chemical parameters, dissolved oxygen
concentrations, pH and temperature (am & pm) (±sd)in
fry rearing tanks concentrations, pH and temperature
(am & pm) (±sd)in fry rearing tanks under different
stocking densities (SD)..................................................... 42
Table 4.2 Mean length on day 14, final mean length, specific
growth rate in length on day 14 and on final day, and
percentage survival of Cyprirms cctrpio fry at different
stocking densities (SD).................................................... 43
X
Table 4.3 Variation of volume of phytoplankton, volume of
zooplankton and Secchi disc depth variation (±sd)
within Cyprinus carpio fry rearing................................. 45
Table 5.1 Dissolved oxygen, temperature, pH and secchi disc
depth in bighead carp PL and grass carp PL rearing
tanks at different stocking densities(SD)........................ 49
Table 5.2 Final mean survival of Aristichthys nobilis PL and
Ctenopharyngodon survival of Aristichthys nobilis PL
and Ctenopharyngodon idella PL reared under
different stocking density regimes and different period
of times............................................................................. 49
Table 5.3 Physico-chemical parameters Temperature, pH and
Secchi disc depth in Cyprinus carpio PL and Ixibeo
rohita PL rearing tanks at different stocking densities... 50
Table 5.4 Percentage survival (±sd) of Cyprinus carpio PL and
Labeo rohita PL reared in different stocking densities... 53
Table 5.5 Mean length variation (±sd) of Cyprinus carpio PL and
Labeo rohita PL reared in different stocking densities... 53
Table 5.6 Specific growth rate in length of Cyprinus carpio PL
and Labeo rohita PL reared in different stocking
densities............................................................................. 54
Table 6.1 Physico-chemical parameters dissolved oxygen,(DO)
pH and secchi disc depth in Cyprinus carpio PL and
Labeo rohita PL rearing tanks under different feeding
regimes.............................................................................. 62
Table 6.2 Percentage survival of Labeo rohita PL and Cyprinus
carpio PL under different feeding regimes......... 63
Table 6.3 Intermediate mean lengths and final mean length (±sd)
of Cyprinus carpio and Labeo rohita fry under
different feeding regimes.................................................. 64
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Table 6.4 Specific growth rate in length on day 7, 14, 21 and final
day of Labeo rohita and Cyprinus carpio fry under
different feeding treatments............................................ 66
Table 7.1 Appearance of plankton species in the fertilized tanks... 74
Table 7.2 Physico-chemical parameters, dissolved oxygen,
temperature, pH and secchi disc depth in tanks
manured with cowdung for natural food culture........... 79
Table 7.3 Proximate analyses of organisms serving as food for
pond fishes........................................................................ 82
Table 8.1 Comparison of the method used in the present study
with the methods of Indrasena & Ellepola (1964)
Ellepola & Fernando (1966) and Hora & Pillay (1962) 89
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List of Figures Page
Fig. 1.1 World fish production (marine and inland)................. 07
Fig. 1.2 Inland fish production in Sri Lanka during the period
1977 to 1996..................................................................... 07
Fig.2.1 The set up of the cement tanks in Udawalawe Fisheries
Station....................................................... 17
Fig. 2.2 The set up of the cement tanks in Ginigathena Fisheries
Station....................................................... 18
Fig.2.3 Selection of squares for counting plankton density
under stero-microscope.................................................. 25
Fig.3.1 Mean length and weight of Aristichthys nobilis postlarvae
reared under different organic manure regimes... 28
Fig.3.2 Dissolved oxygen levels in the control tank and these
that were treated with chicken manure and cowdung... 30
Fig.3.3 Temperature and dissolved oxygen concentration in
tanks under different organic manure regimes................ 32
Fig.3.4 Changes of volume of phytoplankton and zooplankton
and the Secchi disc depth of the control tank and those
treated with cowdung and chicken manure.................. 33
Fig.4.1 Variation of temperature, dissolved oxygen
concentration and pH with time under different
stocking densities............................................................. 41
Fig.4.2 Changes of the volume of phytoplankton, zooplankton
and the secchi disc depth with time................................. 44
Fig.5.1(a) Variation of pH and Secchi disc depth during Labeo
rohita and Cyprinus carpio PL rearing at different
stocking densities............................................................. 51
Fig. 5.1(b) Temperature variation with time in the rearing of postlarvae
of Labeo rohita and Cyprinus carpio under
different stocking densities.............................................. 52
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Fig. 6.1
Fig. 7.1
Fig.7.2
Fig. 7.3
Coefficient of variation of mean length of C. carpio and
Labeo rohita post-larvae reared (a)without
supplementary feed (b) with rice bran and (c )locally
formulated feed............................................................... 65
Variation of temperature, secchi disc depth and pH
with time in culture tanks................................................ 77
Variation of plankton and Secchi disc depth in the
tanks fertilized with cow-dung........................................ 78
Variation of no. of rotifers and Secchi disc depth in
tanks fertilized with cow-dung 78
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List of plates Page
Plate 8.1 The fry in net cage temporarily set in stream (Udawalawe
Fisheries Station) before being transported to.the final
destination............................................................................. 105