Tilapia are a hardy, aggressive freshwater fish originally native to Africa that reproduce quickly and eat a grain-based vegetarian diet. This fish grows fast and can reach a size for harvesting within eight to 10 months. Tilapia is a white fish with a bland flavor that makes it a good substitute for other white fish, including snapper, grouper, flounder, and rockfish. Tilapia is available year-round fresh and frozen, whole and in fillets, and frozen value-added fillets. According to some buyers, the quality of frozen tilapia fillets can vary so it is recommended to stay with a good brand to ensure consistency. Fillets are available in several graded sizes: 3-5 oz, 5-7 oz, and 7-9 oz, with 5-7 oz being the most common grade.
The nature of the fish makes it taste like the water where it was raised, so the best quality has the cleanest taste. Many frozen fillet producers in Taiwan and China treat the fish with carbon monoxide to give the bloodline a red color; these fillets are frequently marketed as sashimi-quality snapper even though they aren’t and do not have the same quality. To make sure their tilapia crop is male, some farmers use a hormone called methyltestosterone that, although deemed safe by the U.S. Food and Drug Administration, has caused some buyers to seek non-treated fish.
Key sustainability sourcing notes for tilapia spp. based on global production from 2016-17 and based on the most recent Seafood Watch assessments and ASC certifications as of October, 2019, are as follows:
~5% of global farm-raised tilapia production is certified to the standards of the Aquaculture Stewardship Council (ASC)
ASC-certified tilapia by country comes from Indonesia ~75%, Brazil ~15%, and China ~10%
For the three primary countries with ASC-certified tilapia, the percentage of the ASC-certified tilapia is ~5% for Brazil and Indonesia, and <1% in China
<1% of global farm-raised tilapia meets a Seafood Watch "Best Choice (green)" rating**; ~90% from Ecuador and ~10% from Peru
~25% of global farm-raised tilapia meets a Seafood Watch "Good Alternative (yellow)" rating; ~85% from Indonesia
~50% of global farm-raised tilapia is unrated; ~35% from Egypt, ~10% each from Philippines, Bangladesh, Vietnam, Brazil, and Thailand
The U.S.** produces ~0.2% of global tilapia production
Global tilapia production increased ~5% from 2016 to 2017
**Tilapia raised in recirculating aquaculture systems (RAS) globally receives a Seafood Watch "Best Choice (green)" rating, but estimates of relative production by RAS are not available. Most tilapia produced in the United States is produced using RAS.
Tilapia have compressed, deep bodies with long dorsal fins. The front part of the dorsal fin is heavily spined. Spines can also be found on the pelvis and anal fins. In earlier life stages, tilapia usually have wide vertical bars down their sides (this physical characteristic can be seen on some adult individuals as well). Tilapia can be distinguished from similar looking fish species by an interrupted lateral line. Their coloring can range from gray or pink to yellowish. Tilapia can grow as large as two feet and can weigh over 10 lbs.
Tilapia will usually reach sexual maturity around five to six months and will start spawning in ponds when the temperature reaches 75o Fahrenheit (24o Celsius). Males will make a nest at the bottom of the pond and then will breed with a number of females. Females will then spawn in the nest – the number of eggs a female releases during spawning is proportional to body weight – with the male fertilizing the eggs. Females hold the fertilized eggs in their mouths until they hatch (the eggs are usually held for about one to two weeks). After hatching, the larvae will feed on the yolk sac for several days, until they venture out to start feeding on their own. The fry (another term for young fish who are capable of feeding themselves) will return to their mother’s mouth for refuge if necessary.
Tilapia are omnivorous grazers. They will feed on phytoplankton, aquatic plants, small invertebrates, larval fish, and detritus. They can filter feed by entrapping particles on the mucus secreted by their gills, though they eat mainly by grazing the water’s surface.
Tilapia are a tropical fish native to Africa and the Middle East. In the wild, tilapia can be found in lakes, wetlands, estuaries, and in marine environments. In Africa, tilapia are native to the Nile River basin, the Niger, Benue, Volta, and Senegal rivers, and Lakes Chad, Tanganyika, Albert, Edward, and Kivu. Tilapia are known for their tolerance to poor water quality. They are; however, relatively sensitive to water temperatures as most tilapia species cannot withstand temperatures below 50° Fahrenheit (10° Celsius) for a few days (blue tilapia can tolerate lower temperatures of about 48° Fahrenheit (8.9° Celsius)). Additionally, most tilapia will stop feeding when water temperatures fall below 63° Fahrenheit (17°Celsius). Of the commercially important species, Nile tilapia are the least tolerant to salinity, but can grow well in salinities up 15 parts per thousand (ppt). Blue tilapia grow well in brackish water up to 20 ppt. Mozambique tilapia are considered to be the most tolerant of salt water and can grow in salinities near or at full saltwater strength.
Tilapia are produced in more than 100 countries making them one of the most widely produced aquaculture species in the world. They have subsequently been purposefully introduced (as biological controls for mosquitos or algae) or accidentally introduced (as a result of escapes from ponds and net pens) into the wild in numerous countries. Some wild populations throughout the world are considered to be invasive as they can disrupt native ecosystems. China is currently the world’s largest producer of farmed tilapia and it is estimated they produce over 40 percent of the world’s supply. The US is considered to be the largest importer of farmed tilapia with most of that fish (estimated at 40 percent) being imported from China.
Science & Management
As tilapia are one of the most commonly farmed fish species, studies have focused on improving growth of the fish and efficient use of resources in farmed tilapia production.
Though tilapia can survive in environments with lower dissolved oxygen (DO) than most other farmed fish, research has shown that they have better growth rates when DO concentrations do not fall below 0.7 mg/L. It has been found that tilapia will grow well in water with salinities up to 15 ppt and can achieve optimal growth when water is around 85-88o Fahrenheit (29-31o Celsius). Researchers at Dartmouth College recently discovered that marine microalgae can be used to replace wild fish oil that is used in feed given to tilapia. Tilapia who ate the microalgae were observed to have “bulked up” more despite being given less feed on this new diet.
Tilapia is one of the largest aquaculture sectors in the United States. Given their sensitivity to temperatures, most US tilapia are farmed using recirculating aquaculture systems or aquaponics systems, while some are also grown in ponds. Tilapia are considered to be fast growing and resilient – making them an ideal aquaculture species.
While there is no national oversight agency for aquaculture in the US, management of US-based farms is considered to be strong and there are extensive regulations in place regarding predator controls, therapeutant use, and disease management. Permitting varies by state with numerous federal agencies providing some degree of oversight. These include:
The United States Department of Agriculture (USDA) – which is responsible for coordinating national aquaculture policy and providing industry with research, information, and extension services;
The Environmental Protection Agency (EPA) – which regulates waste discharge from aquaculture facilities. The EPA authorizes state governments to regulate aquaculture discharges in accordance with National Pollutant Discharge Elimination System (NPDES) permits. These permits help control and monitor discharge levels of solids and other pollutants. Discharge from aquaculture facilities is also subject to additional regulations under individual state laws and agencies;
The Fisheries and Wildlife Service (FWS) – which regulates the introduction and transport of fish; and,
The Food and Drug Administration (FDA) – the FDA’s Center for Veterinary Medicine is responsible for approving and monitoring the use of drugs and medicated feeds used in the aquaculture industry.
China is the world’s largest producer of farmed tilapia. The major production areas are located in south China which due to its warm climate, accounts for roughly 90 percent of total Chinese production. Guangdong, Hainan, and Guangxi provinces supply the majority of Chinese tilapia as the warm temperatures allow for year-round farming. Chinese tilapia are generally farmed using net pens or in ponds (with or without other species). Production systems in China are classified into two categories: integrated systems and specialized systems. Integrated systems are small to medium size and use on-farm wastes to fertilize ponds. These farms cannot obtain the Chinese Inspector Quarantine (CIQ) certification and therefore cannot export. Specialized systems have CIQ certification and are subject to more rigorous controls and inspections. Tilapia in China are also farmed in reservoirs originally built for rice farms.
Despite its importance in China and the US market, there is lack of publicly available information on environmental monitoring and subsequently, the environmental impacts of Chinese tilapia farming. Additionally, information on feeds, effluent management, and escapes is dispersed and considered difficult to access. The Chinese Ministry of Agriculture is responsible for issuing licenses for aquaculture operations; however, it has been difficult for the Ministry to inspect and license the thousands of small farms currently operating. The amount of small-scale facilities operating without a license is unknown and without proper inspection and enforcement, it is impossible to know if they are meeting current Chinese regulations.
There is no specific legislation regarding aquaculture siting in China, but the use of aquatic and terrestrial environments are regulated under different laws, including: the Fisheries Law, the Regulation Law for Sea Area Usage, and the Environmental Impact Assessment (EIA) Law. As all land and water areas are state-owned, siting must meet local zoning schemes required by the Land Administration Law. This particular law also prohibits the use of basic farmland for aquaculture use. Wastewater discharge is regulated under national regulations as well as local governments, though enforcement appears to be almost nonexistent. The national government also establishes laws prohibiting the use of certain chemicals – such as nitrofurans and malachite green – as well as certain antibiotics in aquaculture production.
Tilapia is Indonesia’s most-produced aquaculture product. Production primarily occurs on the islands of Sumatra and Java, which account for about 81 percent of total national tilapia production. Indonesian tilapia are primarily farmed using freshwater ponds (accounting for 75 percent of total production) and marine net pens (which make up the remaining 25 percent). The majority of Indonesian production is consumed domestically. The US and Europe account for the majority of Indonesian exports; however, that amount is relatively small when compared to Chinese tilapia exports. In 2015, Indonesian tilapia accounted for only 4.6 percent of the total US tilapia imports.
The General Directorate of Aquaculture production and Development, a dependent of the Ministry of Marine Affairs and Fisheries, is responsible for farm siting and cumulative aquaculture impacts in Indonesia. The Indonesian Fisheries Act No 31 regulates the environmental impacts of the aquaculture industry. Provincial governments are responsible for the management, use, conservation, and spatial planning of aquatic environments under the Law on Regional Administration while the central government maintains control of issuing licenses for foreign companies. The effectiveness of regulations in Indonesia is hindered by a lack of coordination between the different management agencies. Enforcement of national and regional regulations is also difficult and their success is not fully known. English language information about the overall tilapia aquaculture industry and management in Indonesia is relatively scarce and while production statistics are available, there is a lack of information regarding the ecological impacts of tilapia farming in Indonesia. The environmental impacts of effluents (which are notably lacking in data), land use change, predator control, and chemical use in Indonesia is poorly understood.
In the United States, tilapia farms tends to be held to higher environmental requirements than farms in other countries, according to the New England Aquarium. However, the aquarium says that tilapia farms in Latin America generally have good environmental practices. The Chinese government put guidelines in place in 1990 to prevent alien fish species from being introduced to native populations.
American tilapia systems tend to release small amounts of effluent.
In Asia and Latin America where tilapia farming is intensive, farming can cause local waterways to have higher nitrogen and phosphorous levels, leading to heavier algae growth. Some Mexican tilapia farming operations enhance the habitat by using effluent to irrigate trees, reforesting watershed areas.
Tilapia are farmed in earthen ponds, floating cages, or in indoor recirculating tanks. In the United States, tilapia are farmed in closed tank systems, which reduces the likelihood of escapes. Most tilapia come from farms in Southeast Asia and Latin America. Asian farmers usually treat effluent before discharging it, however poorer rural areas do not always treat it. In Latin America, several independent companies have created best practices for tilapia farming, but the effectiveness of these measures is unclear. Tilapia’s hardy nature reduces the need for pesticides, antibiotics, drugs and other added chemicals. However, the practice in Mexico of raising the fish in drainage water is potentially hazardous due to leaching chemicals. In the United States, the Environmental Protection Agency requires fish farmers to hold discharge elimination permits. American tilapia systems tend to release small amounts of effluent.
Tilapia are vegetarian and primarily fed a grain-based diet. However, some farmers use feed that contains low amounts of fish meal and oil. In Latin America, farmers use feed that contains as much as 8% fishmeal, although it’s usually 5% or less. In Asia, many farmers add fertilizers to the water, encouraging phytoplankton and zooplankton to grow so that less feed is required.
Escapes and Introduced Species
Tilapia are disease-resistant and able to survive in poor water, making the likelihood that escapees will survive very high. Since tilapia are non-native to the United States and threaten native freshwater fish, U.S. farms minimize the risk by employing recirculating systems. Open pond tilapia farming is prohibited in the United States. In Asia, tilapia often escape ponds when they become flooded from rainfall, but their impact on native populations is not fully known. Asian farmers also raise the fish in cages and tanks. Tilapia escapees from tilapia ponds in Central and South America have been linked to the decline of native freshwater fish species. In Mexico, farmed tilapias have been known to spread parasites to native fish.