Questions and Answers
What is the primary reason for the potential of aquaculture in giant freshwater prawns?
In what year did Dr. S.W. Ling close the life cycle of Macrobrachium rosenbergii?
Which of the following locations is NOT mentioned as part of the distribution for Macrobrachium rosenbergii?
Macrobrachium rosenbergii belongs to which subfamily?
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In which type of environments do giant freshwater prawns primarily thrive?
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Which indicator suggests that Macrobrachium rosenbergii larvae are in good condition?
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What is the purpose of the APGAR Method in analyzing M. rosenbergii larvae?
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In the APGAR index, which score signifies the highest level of gut fullness?
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Which characteristic would indicate an unhealthy state in the musculature of M. rosenbergii larvae according to the APGAR criteria?
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What does the appearance of tan/orange blend on the abdominal segment indicate?
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What is the native range of the giant gourami?
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Which of the following is an adaptation of the giant gourami that allows it to survive out of water?
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What maximum size can the giant gourami typically reach?
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What unique physical characteristic do mature male giant gouramis develop?
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Which family does the giant gourami belong to?
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What is the significance of the male giant gourami's behavior during mating?
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How can one distinguish between different types of fins on giant gourami?
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What is the average fecundity of giant gourami based on female weight?
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In which environment do giant gourami prefer to thrive?
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What characteristic of giant gourami eggs contributes to their buoyancy?
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What anatomical feature is specific to both male and female identification in the species discussed?
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Which of the following characteristics allows fish with an arborescent organ to survive in low oxygen conditions?
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What is the role of the barbels found in these fish species?
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What is the optimal temperature range for the discussed fish species' habitat requirements?
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Which morphological characteristic is absent in the fish described?
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What is the maximum concentration of nitrite allowed in the water for optimal catfish reproduction?
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During which season does catfish typically undergo gonadal maturation?
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What occurs if the temperature drops below 22oC in terms of oocyte development?
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What is one method of semi-artificial reproduction that does not involve hormones?
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What percentage of a ripe female catfish's body weight can eggs comprise?
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Study Notes
Monitoring of Larvae
- Schooling behavior and active feeding of larvae indicate good health.
- Microscopic examination allows accurate observation of larval development.
- APGAR Method scores the condition of Macrobrachium rosenbergii larvae based on specific criteria.
APGAR Index Criteria
- Gut Fullness: Ranges from empty to full with fecal strands.
- Gut Lipid Content: No lipid presence to visible globules indicating healthy hepatopancreas.
- Body Coloration: Varies from contracted to well-dispersed chromatophores.
- Pigmentation: Changes from grey/dark bluish to tan/orange blend.
- Setation: Injury ranges from disfigured to intact setae.
- Muscle to Gut Ratio: Distinction between wide/thin gut and muscle thickness in abdominal segment VI.
Introduction to Giant Freshwater Prawn
- Locally known as ulang, promising aquaculture species due to effective larval rearing techniques.
- Species breeds in captivity and exhibits rapid growth.
- Dr. S.W. Ling pioneered breeding efforts in Penang, Malaysia in 1961.
Taxonomic Classification
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Malacostraca
- Order: Decapoda
- Family: Palaemonidae
- Genus: Macrobrachium
- Species: Macrobrachium rosenbergii (giant river prawn)
Distribution and Habitat
- Found in tropical and sub-tropical waters of the Indo-Pacific, including Malaysia, Philippines, and Vietnam.
- Habitat includes freshwater bodies like ponds, rivers, and low-lying areas; capable of moving upstream.
Feeding and Nutrition
- Non-conventional foods are suitable for juveniles and adults during months 3 and 4 of culture.
- Examples of supplemental feeds include cooked squid, freshwater mussels, and rotten vegetables.
Larval Rearing Operations
- Cleaning requires thorough washing with soap followed by chlorination and sun drying for 24-48 hours.
- Prepare brackish water by mixing seawater and freshwater to achieve a salinity of 12 ppt.
Disinfection of Brackish Water
- Use filtered water and disinfect with chlorine solution, ensuring vigorous aeration for 24-48 hours.
Preparation for Breeding
- Bath breeders in 5 ppm povidone iodine for disinfection.
- Stocking rates: 5-7 berried females per square meter in appropriate salinities.
Care for Berried Females
- Maintain water quality with regular replenishment and debris removal.
- Feed high protein diets to enhance egg development.
Disinfection of Newly Hatched Larvae
- Use a 3 ppm povidone iodine solution for disinfection after collection.
Acclimation Process of Post-Larvae
- First post-larvae (PL) appearance occurs after 17 days post-hatching, transitioning to freshwater over 5-6 days at a consistent rate.
Nursery Management of Post-Larvae
- Transfer PL from rearing tanks to nursery tanks with adequate space for growth, aiming for a density of 2,500-3,000 PL/m3.
- Use artificial shelters to minimize cannibalism among the post-larvae.
Feed and Feeding Practices
- Feed PL5 to PL15 with high-protein commercial diets and non-conventional food options, maintaining a feeding schedule of three times daily.
General Information
- Giant gourami (Osphronemus goramy) is significant in both ornamental and edible aquaculture industries.
- Traditionally regarded as a 'savings' method for fish farmers.
Taxonomy
- Kingdom: Animalia
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Actinopterygii
- Order: Perciformes
- Family: Osphronemidae
- Genus: Osphronemus
- Species: Osphronemus goramy
Distribution
- Native to Southeast Asia: Indonesia, Malay Peninsula, Thailand, and Mekong basin.
- Found in 18 countries globally including India, USA (California), Colombia, and Mauritius.
Physical Characteristics
- Largest species in its family, can reach over 70 cm, typically 45-50 cm.
- Possesses a unique labyrinth organ enabling survival out of water for extended periods.
- Mature males develop a prominent 'nuchal hump' and have thicker lips compared to females.
Feeding Habits
- Omnivorous diet, with a significant preference for plant-based foods.
- Also consumes frogs, tadpoles, snails, and small fish.
Habitat Preferences
- Prefers calm, slow-moving waters such as lakes, flood plains, and irrigation canals.
- Optimal water depth for habitat: 0.5 - 1 m.
Reproduction Insights
- Breeding starts at around 3-4 years of age, characterized by low fecundity and oligospemic nature.
- Males are territorial during mating; females lay eggs after being embraced by males.
- External fertilization occurs, with males creating nests to protect eggs.
- Nest construction takes 8-10 days; males guard the nest for 14-21 days post-fertilization.
- Fecundity ranges from 1300 to 2500 eggs per kg of female, with egg diameter of 2-3 mm.
Juvenile Characteristics
- Juveniles exhibit pointed heads, while adults show 8-10 dark vertical bars and a gold-striped appearance.
- Environmental factors like temperature and tranquility significantly impact gonadal development.
Breeding Practices
- Conditioning of breeders should occur separately for a week before stocking for optimal results.
- Stocking ratio is recommended at 1 male per 1 female with a stocking rate of 1 pair for every 3-5 m².
Pond Management
- Draining and drying the pond helps eliminate undesirable species and oxidizes organic matter.
- Incorporating net dividers and filling water to the appropriate depth is crucial before stocking.
- Initial vegetation like kangkong and lemna promotes food sources and nesting materials.
Nest Maintenance and Egg Collection
- Nests consist of plant fibers shaped in sphere or oval designs, sealed to prevent issues during guarding.
- Eggs are buoyant and require careful monitoring and cleaning during collection to remove dead eggs and oil globules.
- Hatching takes approximately 35-40 hours at temperatures between 28-30°C.
Fry Rearing
- Fry are raised until they reach 1.5 - 3 cm before being introduced into grow-out ponds, with an ideal stocking density of 200 per m².
- Nutritional status of broodfish is critical for reproductive success; feeding should consist of high-protein commercial pellets.
Feeding and Monitoring
- Regular feeding twice a day, accounting for 3% body weight, is necessary for health and reproduction.
- Water quality and environmental conditions must be monitored consistently to ensure optimal growth and health of the fish.
Global Distribution
- 80 catfish species identified globally.
- Distribution includes 2 species in America and 1 in Oceania.
Habitat
- Found in freshwater environments such as swamps, rice paddies, lakes, floodplains, and streams.
- Some habitats experience seasonal drying.
Feeding Habits
- Catfish are omnivores and bottom feeders, preferring high-protein diets.
- 70% of their feeding occurs at night, indicating nocturnal behavior.
- They are generally slow foragers.
Morphological Characteristics
- Characterized by 4 pairs of barbels, operculum, and a caudal fin.
- All catfish are scaleless, featuring a lateral line and a pectoral spine.
- Olfactory organs include maxillary, nasal, inner mandibular, and outer mandibular barbels.
Sex Identification
- Females can be identified by the shape and position of the anus and genital papilla compared to males.
Arborescent Organ
- This accessory air-breathing organ resembles cauliflower and aids survival in low oxygen conditions.
- Allows catfish to survive outside water for hours or weeks in muddy environments.
Environmental Requirements
- Optimal temperature for catfish ranges from 25°C to 33°C.
- Dissolved oxygen should be at least 5 mg/L; pH levels should ideally be between 6.5 and 8.0.
- Acceptable ammonia, nitrite, and nitrate levels are 0.125 mg/L, 0.1 mg/L, and 50 mg/L, respectively.
Fecundity
- Ripe females' eggs can constitute 15-20% of body weight, with 600-700 eggs per gram.
- Oocyte development declines below temperatures of 22°C; artificial reproduction results in fewer and lower quality eggs.
Reproduction
- Catfish have a seasonal gonadal maturation, often timed with the rainy season.
- Reproduction is triggered by environmental stimuli like rising water levels.
- Three types of reproduction methods: natural, semi-artificial, and artificial.
Natural Reproduction
- Occurs at night with courtship in shallow waters.
- Males clasp females, releasing eggs and milt simultaneously without parental care.
Semi-Artificial Reproduction
- Utilizes hormone injections to stimulate egg release or simulating rainy season conditions without hormone treatment.
- Procedures vary with hormone-induced reproduction in ponds, hapas, or tanks, maintaining specific stocking densities.
Artificial Reproduction
- Induced breeding allows fish to spawn without specific seasonal triggers, improving fertilization and hatching rates.
- Historical significance with early efforts in induced breeding dating back to 1931, credited to Dr. Hiralal Chaudhuri in India.
Pituitary Gland Role
- The pituitary gland secretes hormones such as gonadotropin, FSH, and LH.
- FSH facilitates ovarian follicle growth and spermatogenesis, while LH promotes testosterone production and luteinization.
Latency Period
- Defined as the interval between hormone injection and egg stripping, varying by species and affected by temperature.
Injection Methods
- Intramuscular injections are administered in muscle, while intraperitoneal injections are given in soft body areas.
Inducing Agents
- Common inducing agents include DOCA, CPG, HCG, and ACPG, each with specific dosages and availability issues.
- Hormone storage requires refrigeration for unused hormones.
Hormone Preparation
- Hormone concentration is determined based on recommended dosages related to fish weight and injection volume for accurate preparation and application.
- Example formulas help establish desired concentrations and volumes for injections in breeding practices.
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Description
This quiz focuses on the monitoring and assessment of Macrobrachium rosenbergii larvae using the APGAR Index. Participants will learn about specific criteria such as gut fullness, lipid content, and pigmentation that indicate health status. Understanding these parameters is crucial for effective aquaculture practices.
