Tilapia is the third most important fish in aquaculture, following carp and salmon. Global production of tilapia exceeded 1.5 million metric tons in 2002 and continues to grow each year. Tilapia is farmed widely because it has high protein content, grows quickly (reaching harvest size in 6 to 7 months), and is easy to eat. Major efforts in aquaculture focus on several species, including Coptodon, Oreochromis, and Sarotherodon, which are types of cichlids.

Tilapia farming began in Africa and the Levant. Tilapia were introduced to freshwater lakes in South and Southeast Asia, both accidentally and intentionally. These introductions led to aquaculture projects in tropical regions such as Honduras, Papua New Guinea, the Philippines, and Indonesia. Tilapia farming in these areas is often considered environmentally friendly because it requires fewer resources. In temperate regions, farmers must use expensive energy to keep water temperatures warm. A sustainable option is to use waste heat from factories or power plants to warm the water.

Tilapia are among the easiest and most profitable fish to farm. They eat a variety of foods, do not go through a stage where their young float in water, and can live in crowded conditions. In some places, tilapia are raised in rice fields and grow to a size suitable for eating when the rice is ready for harvest. Unlike salmon, which need high-protein diets made from fish or meat, tilapia eat plant or grain-based diets.

Tilapia raised in inland tanks or channels are safe for the environment because their waste and diseases are contained and do not spread to wild fish. However, tilapia have become invasive in many subtropical and tropical areas worldwide. Species such as blue tilapia (Oreochromis aureus), Mozambique tilapia (Oreochromis mossambicus), blackchin tilapia (Sarotherodon melanotheron), spotted tilapia (Pelmatolapia mariae), and redbelly tilapia (Coptodon zillii) have established populations in the southern United States, especially in Florida and Texas.

Most commercially grown tilapia are male. Female tilapia can reproduce quickly, leading to large numbers of small fish in ponds or tanks. Whole tilapia can be processed into skinless, boneless fillets. The amount of fillet depends on the size of the fish and how much is trimmed, with yields ranging from 30% to 37%.

Commercial breeding of Nile tilapia

Farming tilapia has been practiced for thousands of years, but breeding tilapia for specific traits began recently. In 1988, a breeding program called GIFT (Genetically Improved Farmed Tilapia) was started by the International Center for Living Aquatic Resources (ICLARM or WorldFish) and Akvaforsk. Scientists combined four wild tilapia strains from Africa with four farmed strains from the Philippines. Today, this GIFT strain is raised in over 87 countries across Asia, Africa, and Latin America.

The GIFT strain is used in breeding programs, such as GenoMar, a company owned by the EW Group. In the past, only growth was considered important when selecting tilapia for breeding. Now, other traits are included, such as growth, fillet yield, robustness, and disease resistance. Robustness is especially important because it helps reduce fish deaths on farms. GenoMar has increased growth by 7% per generation, but fillet yield improves only slightly, about 0.3% per generation. This is because fillet yield is harder to measure on live fish, so scientists use information from related fish instead.

Tilapia breeding uses a method called a "pyramid scheme" with multiple generations. This allows a few high-quality fish to produce billions of fish for farming. Today, the time between generations is 6 to 9 months, meaning more than one generation can be raised each year. Two main methods are used to improve genetics: mass selection and pedigree-based selection. Since 2004, GenoMar has used marker-assisted selection with microsatellites to track parentage. Since 2019, genomic selection using single nucleotide polymorphisms (SNP) has been used more often.

The most recent tilapia genome was completed three years ago. It was developed by NMBU and the University of Maryland. Nile tilapia have 22 pairs of chromosomes and 23 linkage groups due to sex chromosomes. The genome is about 1 billion base pairs long and includes 3,010 contigs arranged into 2,460 scaffolds. These scaffolds match the known chromosome structure. The genome also includes the mitochondrial DNA, and bioinformatics tools estimate there are about 30,000 genes. This information can be accessed through resources like Ensembl or NCBI.

Genomic selection relies on the genetic makeup of fish, not just their family history. This is done using SNP chips, which are tools designed to detect genetic differences. These chips are created after the whole genome is sequenced, focusing on parts of the genome that vary. Dense markers are used because they are closely linked to genes that affect traits, called QTL. Three major SNP chips for tilapia were developed in 2018 and 2020.

RNA sequencing (RNA Seq) is a method to study gene activity. Scientists extract RNA from fish cells, convert it into cDNA, and then sequence it using the same machines used for whole genome sequencing. The process for analyzing RNA data is different from genome sequencing because RNA segments are shorter, making alignment easier. RNA Seq helps scientists understand which genes are active and how much they are used.

Early breeding programs focused mainly on growth. Now, more traits are included, such as disease resistance, reproductive traits, robustness, lower emissions, and better feed conversion (sustainability traits). New technologies, like high-throughput phenotyping in precision farming, may allow even more traits to be studied. Companies are also merging, similar to the poultry industry, which could lead to more use of crossbreeding to improve fish quality. Gene editing, especially with CRISPR-Cas9, is becoming possible and may help improve tilapia. Future farming systems may become more intensive, with fewer ponds, more cages, and more use of recirculating aquaculture systems (RAS). Overall, fish density in farms is expected to increase.

Around the world

Tilapia cichlids are not naturally found in Asia, except for a few species like the Middle Eastern mango tilapia in Western Asia. However, many tilapia species originally from Africa have been introduced to Asia and are now important for food production. China, the Philippines, Taiwan, Indonesia, and Thailand are the main producers of tilapia. In 2001, these countries together produced about 1.1 million metric tons of tilapia, which was about 76% of the world’s total tilapia aquaculture production.

The Food and Agriculture Organization (FAO) has not recorded any tilapia farming in India. The Rajiv Gandhi Centre for Aquaculture (RGCA), which supports aquaculture research in India, has started a project to produce a special type of tilapia called the GIFT strain. This project includes creating a breeding program for the GIFT strain, improving its genetic traits, and training local workers in breeding and genetics. The goal is to develop a fast-growing tilapia strain that can be raised at a low cost. However, commercial tilapia farming is not allowed in India. The RGCA plans to create a breeding program in India, similar to the one used for the GIFT strain in Malaysia and the Philippines, instead of importing the improved fish directly.

The GIFT strain was developed in Malaysia and the Philippines and has grown faster than other tilapia strains by more than 10% per generation. It has been shared with many Asian and Latin American countries. The RGCA project aims to create tilapia strains that grow quickly and can be raised in different farming environments.

The project includes several steps. First, the RGCA will establish a new breeding group of the GIFT strain and design a breeding program to improve its traits in India. Local workers will receive training in selective breeding, genetics, and hatchery management.

Once a high-performing tilapia strain is developed, satellite hatcheries will be created to increase the availability of quality fish and lower costs. These hatcheries will provide improved fish to farmers.

The project will benefit fish farmers, small households, and others, including scientists and consumers. The RGCA will gain knowledge about genetic improvement programs, which can help improve other fish species farmed in India. Farmers and hatchery workers will also learn how to use selective breeding on their farms.

In the long term, the project may help create a full production chain for tilapia. This would require support for farmers, finding low-cost plant-based feed, and improving disease control and growth management. Better harvest and transport methods may also develop as a result.

In 2010, Malawi produced 2,997 tonnes of farmed tilapia. A type of tilapia called 'chambo' (Oreochromis tilapia) is very popular in Malawi and is found in Lake Malawi, Lake Malombe, and the Shire River. However, overfishing has put this fish at risk. Malawi has fish farms that raise tilapia.

• National Tilapia Research and Development Program (NTRDP) – Research on Red Nile Tilapia (Oreochromis niloticus)
• Red Nile Tilapia experiments (CLSU, Philippines)
• Red Nile Tilapia for breeding
• Tilapia fingerlings in breeding tubes
• Water sprinklers for aeration of fingerlings
• Pond setups