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TITLE
DECLARATION
CERTIFICATE-1
CERTIFICATE-2
ACKNOWLEDGEMENT
CONTENTS
LIST OF PLATES
1. INTRODUCTION
1.1. Western Ghats - the Biodiversity Hotspot
1.2. Species Richness and Endemism
1.3. Faunal Distribution – Endemism and Parallelism
1.4. Threats to Biodiversity
1.4.1. Deforestation and Destructive Fishing
1.4.2. Unregulated Damming of Rivers
1.4.3. Increased Accumulation of Pollutants
1.4.4. Indiscriminate Exploitation and Invasive Alien Species
1.4.5. Localised Inbreeding
1.5. Conservation Prospecting
1.5.1. Habitat Restoration
1.5.2. Stakeholder Involvement – Participatory Approaches
1.5.3. Restoration Stocking and Enhancement
1.6. Sustainable Utilisation
1.6.1. Integrated Management
1.7. Fish Biodiversity Conservation in Vembanad Flood Plains
1.7.1. Etroplus suratensis, ‘Pearlspot’
1.7.2. Horabagrus brachysoma, ‘Golden Catfish’
2. REVIEW OF LITERATURE
2.1. Threats to Biodiversity
2.2. Vembanad Wetlands
2.3. Conservation Management
2.4. Ranching and Stock Enhancement
2.5. Biological Attributes for Conservation
2.6. Captive Breeding Protocols
2.6.1. Breeding through Environmental Manipulation
2.6.2. Induced Breeding by Hormonal Manipulation
2.7. Parental Care Behaviour
2.8. Inbreeding- Precaution Measures
2.9. Habitat Management
2.10. Holistic Management
3. MATERIALS AND METHODS
3.1. Life History Traits
3.1.1. Survey on Exploited Fishery Resources
3.1.2. Length – Weight Relationship
3.1.3. Food and Feeding
3.1.4. Reproductive Traits
3.1.4.1. Sex Ratio
3.1.4.2. Maturity
3.1.4.3. Gonado Somatic Index
3.1.4.4. Size at maturity
3.1.4.5. Fecundity
3.1.4.6. Oocyte size frequency profiles
3.2. Captive breeding
3.2.1. Etroplus suratensis
3.2.1.1. Collection of Broodstock and Maintenance
3.2.1.2. Environmental manipulation for Captive breeding
3.2.1.3. Breeding in Raceway System
3.2.2. Horabagrus brachysoma
3.2.2.1. Collection and Maintenance of Brood stock
3.2.2.2. Pond rearing of broodstocks
3.2.2.3. Induced Breeding
Stripping
3.2.3. Larval and post larval development
4. LIFE HISTORY TRAITS OFETROPLUS SURATENSIS (BLOCH)
4.1. Introduction
4.2.Taxonomy
4.3. Diagnostic features
4.4. Results
4.4.1. Fishing Practices and Exploited Fishery Resources
Plate 3. Scare line method
Plate 4. Gill net fishing
Table 4.1. Catch data of Etroplus suratensis in Scare line collections from Vembanad lake (Kumarakom zone)
Table 4.2. Catch data of Etroplus suratensis in Gillnet landings from Vembanad lake (Kumarakom Zone)
Table 4.3. Exploited landings of Etroplus suratensis in Vembanad lake
4.4.2. Length -Weight Relationship
Table 4.4. Size variation of Etroplus suratensis in Scare line fishing
Table 4.5. Size variation of Etroplus suratensis in Gill netting from Vembanad lake
4.4.3. Food and Feeding
Table 4.6. Food and feeding in Etroplus suratensis in Vembanad lake
Table 4.7. Hepato Somatic Index (H.S.I), Gastro Somatic Index (Ga.S.I) &Condition Factor (C.F) of Etroplus suratensis collected from Vembanad lake*
4.4.4. Maturation and Spawning
4.4.4.1. Sexual dimorphism
4.4.4.2. Sex ratio
Table 4.8. Sex ratio of Etroplus suratensis in collections from Vembanad lake
4.4.4.3. Description of gonads and Maturity stages
Plate 5: Testis and Ovary
Plate 6. Position of testis and ovary in E. suratensis
Table 4. 9. Stages of Maturity in Etroplus suratensis
4.4.4.4. Gonado Somatic Index
Table 4.10. Gonado Somatic Index of Etroplus suratensis from Vembanad lake
4.4.4.5. Spawning season and Size at Maturity
Table 4.11. Mature fishes of Etroplus suratensis from Vembanad lake *
Table 4.12. Size at first maturity of Etroplus suratensis in collections fromVembanad lake
4.4.4.6. Fecundity
Table 4.13. Mean Fecundity of Etroplus suratensis from the Vembanad lake
4.4.4.7. Oocyte size frequency profiles
4.5.Discussion
4.5.1. Exploited resources
4.5.1.1. Scare line fishing Vs Padal fishing
4.5.2. Length-Weight Relationship
4.5.2.1. Growth performance of E. suratensis
4.5.3. Food and Feeding behaviour
4.5.4. Reproductive traits of E. suratensis
4.5.4.1. Factors affecting sex ratio, reproductive ecology
4.5.4.2. Gonadal morphology and breeding behaviour
4.5.4.3. G.S.I. variations and spawning season
4.5.4.4. Factors affecting Fecundity
4.5.4.5. Spawning frequency and rhythm in E.suratensis
5. CAPTIVE BREEDING AND SEED PRODUCTION PROTOCOLS OF ETROPLUS SURATENSIS (BLOCH)
5.1. Introduction
5.2. Results
5.2.1. Collection and Maintenance of Brooders
5.2.2. Pond Breeding of E. suratensis
Table 5.1. Egg attachment of Etroplus suratensis in wild (pond)
Table 5.2. Details of pit nurseries made by Etroplus suratensis in pondbreeding
Plate.9. Pits of E. suratensis in earthen ponds
Plate 10. Joint parental care‘pit guarding’
5.2.3. Captive Breeding of Etroplus Suratensis
5.2.3.1. Maturation Assessment and Selection of Brooders
5.2.3.2. Nest building and care of young
Table 5.3. Egg attachment of Etroplus suratensis in raceway systems
5.2.3.3. Egg Incubation in Larval Rearing Tanks
5.2.4. Embryonic Development
Table 5.4. Embryonic development in Etroplus suratensis
5.2.5. Larval And Post Larval Development
5.2.5.1. Newly hatched larva
5.2.5.2. Hatchling – 2 day old
5.2.5.3. Hatchling – 3 day old
5.2.5.4. Hatchling – 4 day old
5.2.5.5. Hatchling – 5 day old
5.2.5.6. Hatchling – 6 day old
5.2.5.7. Nursing of hatchlings
5.3. Discussion
5.3.1. Pond breeding of E. suratensis
5.3.1.1. Decreased turbidity favour visual displays
5.3.1.2. Shallow water conditions
5.3.2. Artificial raceways and simulated situations
5.3.3. Artificial spawning substrates
5.3.4. Spawning rhythm and lunar periodicity
5.3.5. Coloration and reproductive readiness
5.3.6.Territoriality and spawning
5.3.7. Tank breeding with Parental patronage
5.3.7.1. Substrate brooding to mouth brooding among cichlids
5.3.7.2. Parental care behaviour
5.3.7.3. Pit caring
5.3.7.4. Parental care and larval nutrition
5.3.8. Larval Development and Fry Nursing
6. LIFE HISTORY TRAITS OFHORABAGRUS BRACHYSOMA (GUNTHER)
6.1. Introduction
6.2.Taxonomy
6.3. Diagnostic features
6.4. Results
6.4.1. Exploited catches and fishing practices
Table 6.1.a. Catch composition of H. brachysoma from the riverine stretches ofVembanad lake
Table 6.1.b. Seasonal variation in exploited catches of H. brachysoma
6.4.2. Length -Weight Relationship
Table 6.2. Size variation of Horabagrus brachysoma in Gill netting from theriverine stretches of Vembanad lake
6.4.3. Food and Feeding
Table 6.3. Food and feeding in Horabagrus brachysoma in Vembanad lake
Table 6.4. Hepato Somatic Index (H.S.I), Gastro Somatic Index (Ga.S.I) andCondition Factor (C.F) of H. brachysoma collected from Vembanad lake*
6.4.4. Maturation and Spawning
6.4.4.1. Sexual dimorphism
6.4.4.2. Sex ratio
Table 6.5. Sex ratio of Horabagrus brachysoma in collections fromVembanad lake
6.4.4.3. Description of gonads and Maturity Stages
6.4.4.4. Gonado Somatic Index
Table 6.6. Stages of Maturity in Horabagrus brachysoma
Table 6.7. Gonado Somatic Index of Horabagrus brachysoma collected fromVembanad lake
6.4.4.5. Spawning season and Size at Maturity
Table 6.8. Mature fishes of Horabagrus brachysoma from Vembanad lake*
Table 6.9. Size at first maturity of Horabagrus brachysoma in collections fromVembanad lake
6.4.4.6. Fecundity
Table 6.10. Fecundity indices of Horabagrus brachysoma fromVembanad lake*
6.4.4.7. Oocyte size frequency profiles
6.5. Discussion
6.5.1.Exploited resources
6.5.2.Length –weight relationship
6.5.3. Nocturnalism in catfishes
6.5.4. Food and feeding behaviour
6.5.5. Reproductive traits in H. brachysoma
6.5.5.1. Factors influencing sex ratio
6.5.5.2. Gonadal morphology and breeding behaviour
6.5.5.3. G.S.I Variations and breeding seasons
6.5.5.4. Factors influencing Fecundity
6.5.5.5. Egg size and Fecundity
6.5.5.6. Ovarian type and breeding strategies in H. brachysoma
7. CAPTIVE BREEDING AND SEED PRODUCTION PROTOCOLS OF HORABAGRUS BRACHYSOMA (GUNTHER)
7.1. Introduction
7.2. Results
7.2.1 Collection and maintenance of brooders
7.2.2. Maturation Assessment and Selection of Brooders
Plate 25.Sexual dimorphismin H. brachysoma
7.2.3. Induced Breeding by Hormonal Manipulation
Plate 26.Breeding set of H. brachysoma
Plate 27.Hormone injection
Table 7.1. Captive breeding trials in Horabagrus brachysoma
Table 7.2. Response of Horabagrus brachysoma to Ovaprim and Carp pituitaryExtract (CPE)
Table 7.3. Breeding trials in Horabagrus brachysoma
Table 7.4. Performance of females during captive breeding
7.2.3.1. Viability of ova
7.2.3.2. Stripping/Artificial fertilisation
Table 7. 5. Spawning Fecundity in Horabagrus brachysoma
7.2.4. Breeding behaviour
Table 7.6. Captive Breeding protocols of Horabagrus brachysoma
7.2.5. Embryonic Development
Table 7.7. Embryonic Development in Horabagrus brachysoma
7.2.6. Larval and Post larval Development
7.2.6.1. Newly hatched larva
7. 2.6.2. Hatchling – 2 day old
7. 2.6.3. Hatchling – 3 day old
7. 2.6.4. Hatchling – 4 day old
7. 2.6.5. Nursing of hatchlings
7.3. Discussion
7.3.1. Induced maturation by hormonal manipulation
7.3.2. Hormonal analogues
7.3.3. Stripping in catfishes
7.3.4. Latency period and ova viability
7.3.5. Eggs expelled in spawning bout
7.3.6. Courting and Spawning
7.3.7. Egg size and survival
7.3.8. Embryonic development and hatching
7.3.9. Larval rearing and fry nursing
Captive breeding and Conservation Management
GRAPHS
Fig.4.1. Catch composition of Etroplus suratensis in total finfish landings fromVembanad lake
Fig.4.2. Exploited landings of Etroplus suratensis in Vembanad lake
Fig.4.3. Catch Per Unit Effort of Etroplus suratensis in scare line fishing
Fig. 4.4. Catch Per Unit Effort of Etroplus suratensis in gill netting
Fig.4.5. Length frequency distribution of Etroplus suratensis from Vembanadlake
Fig.4.6. Size variation of Etroplus suratensis among male and female fishes
Fig.4.7. Size frequency distribution of Etroplus suratensis in gill net and scareline catches
Fig.4.8. Length weight relationship of Etroplus suratensis -Male
Fig.4.9. Length weight relationship of Etroplus suratensis -Female
Fig.4.10. Length weight relationship of Etroplus suratensis -Juvenile
Fig.4.11. Dominant Food components of Etroplus suratensis
Fig.4.12. Percentage Index of various degrees of fullness of the gut inEtroplus suratensis
Fig.4.13. Relative Length of Gut in Etroplus suratensis
Fig.4.14. Sex ratio of Etroplus suratensis in Vembanad lake
Fig.4.15. Distribution of oocytes in different stages of ovary in Etroplussuratensis
Gonado Somatic Index in male Etroplus suratensis from Vembanad lake
Fig.4.16. Male
Fig. 4.17. Female
Fig.4.18. Seasonal distribution of mature fishes of Etroplus suratensis in Vembanad lake
Size at first maturity of Etroplus suratensis in collections from Vembanad lake
Fig. 4.19 - Male
Fig. 4.20. Female
Fig.4.21. Length- Fecundity relationship in Etroplus suratensis
Fig.4.22. Weight- Fecundity relationship in Etroplus suratensis
Fig.4.23. Ovary Weight- Fecundity relationship in Etroplus suratensis
Fig.4.24. Fluctuations on ova diameter (mm) of Etroplus suratensis
Fig.5.1. Nest formation of Etroplus suratensis under controlled conditions
Fig.5.2. Growth performance of post larvae - Etroplus suratensis
Fig.6.1. Catch details of Horabagrus brachysoma in different riverine zones, Vembanad lake
Fig.6.2. Size distribution of male and female Horabagrus brachysoma
Fig.6.3. Length frequency distribution of Horabagrus brachysoma in riverinezones, Vembanad lake
Fig.6.4. Length weight relationship of Horabagrus brachysoma -Male
Fig.6.6. Length weight relationship of Horabagrus brachysoma - Juveniles
Fig. 6.7. Food Composition of Horabagrus brachysoma
Fig. 6.8. Percentage Index of various degrees of fullness in the gut ofHorabagrus brachysoma
Fig. 6.9. Relative Length of Gut in Horabagrus brachysoma
Fig. 6.10. Frequency distribution of male and female Horabagrus brachysoma
Fig. 6.11. Horabagrus brachysoma – Oocyte size Distribution
Gonado Somatic Index in female Horabagrus brachysoma
Fig. 6.12. Male
Fig.6.13. Female
Fig. 6.14. Seasonal distribution of mature fishes of Horabagrus brachysoma0102030405060708090100J F M A M J J A S O N DMonth% of mature fishes Mature male Immature maleMature female Immature female
Size at first maturity of Horabagrus brachysoma
Fig. 6.15. Male
Fig.6.16. Female