Tilapia has become the third most important fish in aquaculture after carp and salmon; worldwide production exceeded in 2002 and increases annually. Because of their high protein content, large size, rapid growth (6 to 7 months to grow to harvest size), and palatability, a number of coptodonine and oreochromine cichlids—specifically, various species of Coptodon, Oreochromis, and Sarotherodon—are the focus of major aquaculture efforts.
Tilapia fisheries originated in Africa and the Levant. The accidental and deliberate introductions of tilapia into South and Southeast Asian freshwater lakes have inspired outdoor aquaculture projects in various countries with tropical climates, including Honduras, Papua New Guinea, the Philippines, and Indonesia. Tilapia farm projects in these countries have the highest potential to be "green" or environmentally friendly. In temperate zone localities, tilapia farmers typically need a costly energy source to maintain a tropical temperature range in their tanks. One relatively sustainable solution involves warming the tank water using waste heat from factories and power stations.
Tilapiines are among the easiest and most profitable fish to farm due to their omnivorous diet, mode of reproduction (the fry do not pass through a planktonic phase), tolerance of high stocking density, and rapid growth. In some regions the fish can be raised in rice fields at planting time and grow to edible size () when the rice is ready for harvest. Unlike salmon, which rely on high-protein feeds based on fish or meat, commercially important tilapiine species eat a vegetable or cereal-based diet.
Tilapia raised in inland tanks or channels are considered safe for the environment, since their waste and disease is contained and not spread to the wild. However, tilapiines have acquired notoriety as being among the most serious invasive species in many subtropical and tropical parts of the world. For example, blue tilapia (Oreochromis aureus) (itself commonly confused with another species often used in aquaculture, the Nile tilapia, O. niloticus), Mozambique tilapia (O. mossambicus), blackchin tilapia (Sarotherodon melanotheron), spotted tilapia (Pelmatolapia mariae), and redbelly tilapia (Coptodon zillii) have all become established in the southern United States, particularly in Florida and Texas.Non-Native Aquatic Species Summaries
Commercially grown tilapia are almost exclusively male. Being prolific breeders, female tilapia in the ponds or tanks will result in large populations of small fish. Whole tilapia can be processed into skinless, boneless (PBO) fillets: the yield is from 30% to 37%, depending on fillet size and final trim. __TOC__
Commercial breeding of Nile tilapia Although farming of Tilapia has been going on for thousands of years, the breeding of Tilapia did not start until recently. The first breeding program started in 1988 in a collaboration between the international center for living aquatic resources (ICLARM or WorldFish) and Akvaforsk. The name of the project was GIFT, meaning genetically improved farmed tilapia. Four wild strains from Africa were crossed with four farmed strains from the Philippines. This strain is currently farmed in more than 87 countries in Asia, Africa and Latin America.
The GIFT strain is used in two selection programs, one of them being GenoMar, a subsidiary EW Group. In the past the absolute and only important trait when breeding tilapia was growth, being the only criteria for selection. Today more traits have been added into the selection criteria, like growth, fillet yield, robustness and specific disease resistance. Robustness is one of those traits that is becoming more important since it is the biggest problem with mortality on farms today. GenoMar has successfully had a growth increase of 7% per generation while fillet yield only improves with 0,3% per generation. The explanation for this is its low heritability together with the fact that the trait cannot be measured on live animals and therefore information of fillet yield is given from relatives instead.
Breeding of Tilapia is done with the help of a pyramid scheme with multiplying generations. The goal with this is that a few high merit individuals can be passed down into billions of production fish at the farms. The generation interval today is down to only 6-9 months meaning that there can be more than one generation per year. Mass selection and pedigree-based selection are the most used methods today for genetic improvements of tilapias. The breeding program GenoMar has used marker-assisted selection since 2004 using microsatellites when doing parentage assignment has been done on Tilapia. Since 2019 genomic selection using single nucleotide polymorphic (SNP) has been used more widely.
The latest genome assembly is from 3 years ago, and can be seen from the name of the assembly that NMBU was also highly involved in the effort along with the University of Maryland. Nile tilapia have 22 pairs of chromosomes. 23 Linkage groups because of the sex chromosomes. About 1 billion base pairs in length, 3,010 contigs made 2,460 scaffolds which were placed at a chromosome level as the karyotype was already known. The reference genome also has the non-nuclear mitochondrial genome. With help from bioinformatics, the estimated number of genes is around 30 thousand. It can be browsed in ensembl or NCBI for example.
The essential technological foundation for genomic selection is not obtaining the pedigree but the genotypes of the animals. This is currently done by SNP chips, oligonucleotide arrays. They have to be specifically designed for a species and commonly that is done based after the whole genome sequence has been obtained. Only some parts of the WGS are of interest, namely those that exhibit variation. Dense markers are considered good enough to capture the gene content because they are in linkage disequilibrium with the genes that influence the phenotype, or as they are called QTL. There are three major SNP chips for Tilapia, which were announced in 2018, 2020 and then 2020 again. In RNA Seq, the RNA from cells of a tissue is extracted and they are sequenced in order to know what genes are being expressed and at what intensities. First, the extracted RNA is converted into cDNA and that cDNA library is sequenced using the same machines used in whole genome sequencing. The bioinformatics pipeline afterwards is different from WGS, though. Since the segments are shorter, alignment is not as difficult. Also, one is interested in the amount of transcription that is happening. In any case, RNA Seq provides valuable insight into the biology of a group of cells and the entire organism.
In the beginning, breeding programs focused mainly on growth traits. Nowadays, more traits are included in the breeding goal. The tendency is to have even more traits in the future. For example, disease resistance, reproductive traits, robustness, lower emissions, feed conversion ratio (sustainability traits). New technologies for high-throughput phenotyping, as in the concept of precision farming, mean that many novel traits might be included as well. There is already a tendency to have mergers and acquisitions, with a few companies buying smaller ones, just like it happened in the poultry industry. Also like the poultry industry, the exploitation of heterosis is a possibility that could be established in Tilapia breeding. This would mean more protection for the companies and attract more corporate enterprises. Because crossbreeding provides a biological lock mechanism. Gene editing is coming. Especially CRISPR-Cas9 can already be implemented and holds a lot of promise. We also expect for the production systems to become ever more intensive. This means fewer ponds, more cages and more RAS. Overall, the average fish density is going to increase.
Nutritional value
Tilapia from aquaculture contain especially high ratios of omega-6 to omega-3 fatty acids.
Around the world Apart from the very few species found in the Western Asia, such as the Middle Eastern mango tilapia, there are no tilapia cichlids native to Asia. However, species originally from Africa have been widely introduced and have become economically important as food fish in many countries. China, the Philippines, Taiwan, Indonesia, and Thailand are the leading suppliers, and these countries altogether produced about of fish in 2001, constituting about 76% of the total aquaculture production of tilapia worldwide.
Production of farmed tilapia from the top 20 countries in 2017 Country Tonnes Notes China 1,188,480 In mainland China, tilapia is called () in Mandarin that is ultimately based on the Vietnamese word, cá rô phi. Indonesia 1,260,000 In Indonesia, tilapia are known as either mujair, referring to fish closer to the wild type coloration and conformation, or ikan nila, "nila" referring to the bright color of the common red hybrid. Tilapia were introduced to Indonesia in 1969 from Taiwan. Later, several species also introduced from Thailand (Nila Chitralada), Philippines (Nila GIFT) and Japan (Nila JICA). Tilapia has become popular with local fish farmers because they are easy to farm and grow fast. Major tilapia production areas are in West Java and North Sumatra. In 2006, Badan Pengkajian dan Penerapan Teknologi (Agency for the Assessment and Application of Technology) and Balai Besar Pengembangan Budidaya Air Tawar (Main Center for Freshwater Aquaculture Development – MCFAD), Indonesian government research, development and introduced a new species named "genetically supermale Indonesian tilapia" (GESIT). GESIT fish are genetically engineered to hatch eggs that will produce 98% - 100% male tilapia. Monosex culture (all male) is more productive and will benefit the farmers. Now, around 14 strains of ikan nila have been developed by contributions from research institutes including MCFAD. Egypt 967,301 Brazil 550,050Tilapia production in Brazil increased 3 - 4 percent in 2022. Philippines 267,735 In the Philippines, several species of tilapia have been introduced into local waterways and are farmed for food. Tilapia fish pens are a common sight in almost all the major rivers and lakes in the country, including Laguna de Bay, Taal Lake, and Lake Buhi.
Locally, tilapia are also known as "pla-pla". Tilapiine cichlids have many culinary uses, including fried, grilled, sinigang (a sour soup using tamarind, guava, calamansi or other natural ingredients as a base), paksiw (similar to sinigang, only it uses vinegar) and many more recipes.
On January 11, 2008, the Cagayan Bureau of Fisheries and Aquatic Resources (BFAR) stated that tilapia production grew and Cagayan Valley is now the Philippines' tilapia capital. Production grew 37.25 percent since 2003, with 14,000 tonnes (MT) in 2007. The recent aquaculture congress found the growth of tilapia production was due to government interventions: provision of fast-growing species, accreditation of private hatcheries to ensure supply of quality fingerlings, establishment of demonstration farms, providing free fingerlings to newly constructed fishponds, and the dissemination of tilapia to Nueva Vizcaya (in Diadi town). Vietnam 235,311 Thailand 203,696 The red hybrid is known in Thai language as pla thapthim (), whereas the black and silver striped hybrid is known as pla nin (; lit. "Nile fish"). Both hybrids of tilapia O. niloticus are very popular in Thai cuisine.