You may have heard tilapia referred to as “garbage fish”. However, most people who know fish, fish production and the value of captured and cultured fish consider tilapia “the miracle fish” or “the wonder fish”.
Egyptians have been culturing this freshwater fish for over 4,000 years. Clearly identifiable images of tilapias appear among ancient Egyptian hieroglyphs.
There are about 70 species of tilapia, of which 9 have been used for commercial production. There has been a great effort in identifying and systematizing the classification of these fishes which is highly complex mostly because they are ancient fish with a great affinity for hybridization. Tilapia has been introduced for culture to practically every continent with the exception of Antarctica. The best known and the most widely cultured species is the Nile Tilapia (Oreochromis niloticus). The Nile Tilapia is produced in about 85 countries around the world. About 98 per cent of all tilapias cultured in the world belongs to this species or to some of its hybrids with a closely related species, the Blue tilapia (O. aureus).
In 2017, the total production of tilapia (wild capture and cultured fish) was about 7,5 million metric tonnes. In 2018, the total value of tilapia sales worldwide was about US$12,000,000,000. Most of the output of cultured tilapia comes from China and Egypt with 42 and 14 per cent, respectively. Other important tilapia producers in Asia are Indonesia, the Philippines and Malaysia, while the major producers in Latin America are Mexico, Brazil and Colombia. The main market for cultured tilapias is the United States. Other important markets, especially for tilapia produced in China, are Mexico and Russia.
Tilapias are also produced in Canada. Farms for tilapia culture using heated water in indoor tanks exist in British Columbia and Alberta. Toronto is the largest market for live tilapia in North America. Other important markets for Canadian-produced live tilapia are Vancouver, Calgary and Edmonton.
In the United States tilapia is cultured in several states including Arizona, Texas and California, however, most tilapia growing operations are located in Idaho and use greenhouses, industrial waste heat or geothermal water resources in recirculating systems to produce live tilapia most of which supplies the demand of the large Asian population living in Vancouver.
Because of my work, I know about tilapias; I have studied their reproductive and survival requirements, their selective breeding and genetic improvement. I have eaten them in many preparations, and it is a delicious fish. Far from being a “garbage fish”, tilapia is an extremely valuable fish well deserving of its high reputation.
Furthermore, tilapias are beautiful fish!
EDITED 02–05–19
Thanks to all readers who have upvoted my answer to the question on tilapia as a “garbage fish”.
In response to several comments, I believe there are two aspects that deserve additional information and clarification:
1) On the subject of “tilapia feeding on fecal material”:
Wild tilapia are omnivorous, however, they prefer aquatic plants and consume most forms of algae. Tilapia farming operations (fish grown in ponds at a rate of 100 fish/meter^3) regularly allow the fish at various life stages to feed on algae, floating aquatic plants and submerged plants. Because of the higher stocking density than fish in the wild, nutrients that sustain the growth of vegetation in the pond must be supplemented or the fish may stop growing, starve or become stressed. To achieve increased plant production in the pond, animal manures (from water buffalo, horse, chicken or duck) are used as fertilizers. In some low-intensive operations, inorganic fertilizers such as urea and TSP ( tri-sodium phosphate) are applied to provide nutrients that stimulate the growth of protein-rich phytoplankton, which is consumed by filter-feeding tilapia.
At this point is worth recalling that intensive agriculture operations also enrich the soil by using inorganic fertilizers and manure to enhance the yield of vegetable crops. Additionally, the production of the common mushroom (Agaricus bisporus) relies on cow, chicken or horse manure as a substrate and nutrient to grow the mushrooms.
A well-run tilapia farming operation normally uses manure to provide nutrients for aquatic plants growth that feed the tilapias, and not as direct food for the fish.
2) On the subject of “muddy taste of tilapias”:
Several commercially important cultured freshwater fish (carp, catfish, tilapia, trout, etc.) may have a rather unpleasant “muddy taste”. This is caused by a compound called “Geosmin”. This compound, also known as Cyclododecanone [C12H22O] is produced by the gram-positive bacteria Streptomyces and various cyanobacteria naturally present in the water and it’s released when these micro-organisms die. In such occasions, Geosmin combines with 2-methylisoborneol [C11H20O], a compound also present in water produced by blue-green algae, such as Anabaena. The ensuing combined compound can concentrate in the fatty skin and dark muscle tissues of the fish resulting in the muddy taste. The good thing is that [Geosmin + 2-methylisoborneol] easily breaks down in acid conditions; soaking the fish filets in vinegar or other acidic ingredient (lemon juice) can reduce or eliminate the muddy flavor.