The three methods of breeding or propagation of cultured fish are natural breeding, artificial breeding, and induced breeding.
1. Natural Breeding: Natural breeding refers to the reproduction of fish in their natural environment without any human intervention. In this method, fish are allowed to breed naturally in ponds, lakes, or rivers. The fish are provided with suitable conditions such as proper water quality, temperature, and adequate food supply to encourage spawning. Natural breeding is commonly used for species that are easy to breed and have a high reproductive rate. However, it is difficult to control the breeding process and ensure the desired genetic traits in the offspring.
2. Artificial Breeding: Artificial breeding involves the manipulation of fish reproduction by human intervention. This method is commonly used for species that are difficult to breed naturally or have low reproductive rates. In artificial breeding, fish are induced to spawn by manipulating environmental conditions such as temperature, light, and water quality. The eggs and sperm are collected from the fish and fertilized externally in a controlled environment. The fertilized eggs are then incubated in hatcheries until they hatch into fry. Artificial breeding allows for better control over the breeding process and enables the selection of desired genetic traits.
3. Induced Breeding: Induced breeding is a specific form of artificial breeding that involves the use of hormones or chemicals to stimulate fish to spawn. This method is commonly used for species that have specific breeding requirements or do not breed naturally in captivity. Hormones such as gonadotropin-releasing hormone (GnRH) or luteinizing hormone-releasing hormone (LHRH) are injected into the fish to induce spawning. The timing and dosage of hormone administration are crucial to ensure successful breeding. Induced breeding allows for precise control over the breeding process and facilitates the mass production of fish fry.
Each method of breeding or propagation of cultured fish has its advantages and limitations. The choice of method depends on the species being cultured, the desired genetic traits, and the availability of resources and expertise.