Producing healthy fingerlings is a critical stage in fish hatchery management, directly influencing the success of aquaculture operations in Kenya. This chapter focuses on the essential practices involved in preparing breeding facilities and selecting suitable broodstock to ensure optimal reproduction and survival rates. Effective cleaning of breeding tanks, jars, and equipment reduces disease risks, while the selection of ripe broodstock guarantees high-quality fertilization and viable offspring. These practices form the foundation for sustainable fingerling production in diverse Kenyan aquaculture setups, from small-scale tilapia farms to larger catfish hatcheries.

6.1 Cleaning of Breeding Facilities and Fingerling Rearing Equipment

Maintaining hygiene in breeding and fingerling rearing facilities is paramount in preventing contamination and disease outbreaks. In Kenya’s aquaculture industry, where water quality and biosecurity are often challenged by environmental and resource constraints, rigorous cleaning protocols safeguard fingerling health and improve survival rates. Cleaning involves all equipment that comes into contact with broodstock and fingerlings, including tanks, breeding jars, hapa nets, and work surfaces such as tables.

6.1.1 Tanks, Breeding Jars, and Hapa Nets

Tanks, breeding jars, and hapa nets serve as the primary containment units in fish hatcheries, making their cleanliness vital for fish health. These containers must be free from organic waste, algae, and pathogens that could impair egg fertilization or fingerling development.

Cleaning Procedures for Tanks and Breeding Jars

• Removal of Residual Organic Matter: After each breeding cycle, all organic debris such as uneaten feed, feces, and dead eggs must be physically removed using scrapers or brushes to prevent fungal and bacterial growth.
• Use of Appropriate Disinfectants: A dilute solution of potassium permanganate or sodium hypochlorite is commonly applied to disinfect tanks and jars. The concentration and exposure time must be carefully controlled to avoid damage to equipment and residual toxicity.
• Rinsing and Drying: Thorough rinsing with clean water eliminates chemical residues. Tanks are then air-dried or exposed to sunlight, which provides natural ultraviolet sterilization.
• Regular Inspection for Damage: Cracks or biofilm buildup on tank surfaces can harbor pathogens; these must be repaired or replaced promptly to maintain a sterile environment.

Maintenance of Hapa Nets

• Cleaning and Sterilizing: Hapa nets, which are used to isolate broods or fingerlings, accumulate mucus and algae. They should be washed with fresh water and disinfected with mild bleach solutions before reuse.
• Drying and Storage: Nets must be dried completely to prevent microbial proliferation and stored in a clean, dry place away from direct sunlight to prolong their lifespan.
• Avoiding Cross-Contamination: Separate hapa nets should be designated for different breeding groups to prevent disease transmission between stocks.

6.1.2 Tables and Work Surfaces

Work surfaces such as tables where eggs are handled, sorted, or fertilized must uphold strict hygiene standards to avoid pathogen transfer.

Cleaning Protocols for Tables

• Daily Cleaning Routine: Tables should be wiped down with clean water and detergent after each use to remove organic matter.
• Disinfection: Surfaces must be disinfected with alcohol-based or chlorine-based solutions, ensuring contact times are sufficient to neutralize microbes.
• Use of Non-Porous Materials: Tables constructed from stainless steel or plastic are preferable as they resist scratches and biofilm formation better than wood.
• Regular Surface Inspection: Cracks or grooves where dirt accumulates require repair or replacement of the table surface to maintain cleanliness.
• Personal Hygiene Practices: Hatchery staff should wash hands thoroughly and use gloves when handling eggs or fingerlings to minimize contamination risks.

Chapter Summary

This chapter covers the essential practices involved in producing fingerlings in fish hatchery management. It begins with the cleaning of breeding facilities, including tanks, breeding jars, hapa nets, and tables, to ensure a hygienic environment for breeding. The selection of ripe broodstock is discussed as a critical step for successful reproduction, followed by an exploration of different types of breeding methods. Artificial propagation techniques such as stripping, fertilization, and incubation of eggs are explained to enhance breeding efficiency. The chapter also addresses monosex tilapia production and the preparation of hormone-treated feed to control reproduction. It highlights the stages of hatchlings at first feeding and outlines the appropriate duration of feeding for optimal growth. Live feed culture is detailed with a focus on algae, Artemia, rotifers, and copepods, while nursing fry and feeding practices are described to support early development. Finally, the importance of grading fingerlings to maintain uniform size and quality is emphasized.