After the significant increases in meat and chicken prices over recent years, Um Amr, a housewife with four children who lives in Cairo, began purchasing tilapia fish two to three times a month to provide protein for her family at a relatively low cost.

Like for many Egyptians, tilapia has always been a “refuge” for Um Amr and her family. She buys two kg of tilapia fish for LE120 from the local market, while one kg of chicken costs LE165 and one kg of meat costs LE350. She chooses tilapia as a cheaper option.

However, this refuge has now been threatened by the accumulation of pollutants in natural fisheries.

Studies conducted by researchers at the National Institute of Oceanography and Fisheries at locations along the Nile and in various lakes have revealed that levels of pollution, including of heavy metals and polycyclic aromatic hydrocarbons, chemicals produced when fossil fuels are burned, exceed permissible limits in some aquatic environments in Egypt.

These areas hold large quantities of pollutants, which hurt the health of tilapia and other species of fish. As a result, the fish accumulate pollutants in their vital organs, posing a potential long-term health risk to consumers.

The presence of the tilapia fish in Egypt dates back thousands of years, as the ancient Egyptians recognised it and depicted it in temple paintings. Today, tilapia remains the most popular fish in the country.

Egypt also ranks first in tilapia production in Africa and third in the world. In 2021, it saw total fish production of 2.3 million tons across various species, with tilapia alone accounting for more than half of this output.

Fish farming accounts for 85 per cent of tilapia production, compared to 15 per cent for natural fisheries, according to the annual production statistics bulletin issued by the Central Agency for Public Mobilisation and Statistics (CAPMAS) in May 2023.

The average production of tilapia from fish farming is increasing at an annual rate of 11.8 per cent, compared to a decline in productivity from natural fisheries at an annual rate of 1.85 per cent, according to “An Economic Study of Tilapia in Egypt” published in the Egyptian Journal of Agricultural Economics in 2019, which compared annual production rates from 2000 to 2016.

Today, pollution is significantly contributing to the decline in fish production from natural fisheries. Sally Salaheddin, an assistant professor at the National Institute of Oceanography and Fisheries, said that “through my study of various fish species, I have identified numerous sources of pollution that affect the aquatic environment. This has negatively impacted both the numbers and the productivity of fish species.”

She said that a comparison of the numbers and types of fish produced over the years shows a notable decline in the diversity of species and quantities in lakes and other water bodies in Egypt.

“There are now certain fish that we no longer see in the markets,” she explained. “This decline is due to various factors, including their inability to survive in polluted conditions. Fish may also migrate from one location to another in search of a cleaner environment, which results in certain lakes becoming devoid of specific species that cannot tolerate pollution.”

Tilapia is known for its resilience and characteristics that enable it to survive challenging conditions, Salaheddin said. “Studies have shown that tilapia can withstand stressful environmental factors, such as varying temperatures and relatively high levels of pollution, better than other fish species. Tilapia is also highly tolerant to a wide range of salinity and low oxygen levels, which enhances its chances of survival in diverse environments.”

“Tilapia fish have a high tolerance for various pollutants, which allows them to accumulate these harmful substances in their bodies. But as these pollutants build up, they can damage vital organs such as the liver, gills, and kidneys.”

“In a series of studies conducted at our institute, we observed elevated levels of pollutants and heavy metals in these organs. The greater the accumulation of pollutants, the more dangerous it becomes for both the fish and those who consume them,” Salaheddin said.

Studies: A study conducted by the National Institute of Oceanography and Fisheries published in May 2024 measured the levels of polycyclic aromatic hydrocarbon (PAH) pollution in Lake Manzala and its impact on some fish species such as the Nile tilapia.

The study found that PAH pollutants in the water exceeded permissible levels in certain areas affected by heavy anthropogenic activities. Histological examinations of fish tissue samples showed several changes, indicating a direct relationship with concentrations of Benzo(a)pyrene, a highly potent carcinogen, in the tissues of the fish, especially those from heavily polluted areas, exceeding EU guidelines.

The study warned that high levels of PAH pose a carcinogenic risk to tilapia consumers if long-term pollution rates continue as they are.

Lake Manzala ranks second in tilapia fish production among lake fisheries in Egypt, its production amounting to 38,000 tons a year, after Lake Borollos, which ranks first (57,000 tons in 2021), followed in third place by Lake Nasser (21,000 tons), according to CAPMAS in 2021.

Despite the concerning indicators about pollution, there is some good news, as Salaheddin explained. The organ where the fish typically store the least amount of toxins is the muscle, which is the edible part of the fish. However, consuming large quantities of fish can still be dangerous, particularly for coastal residents, and may lead to long-term health risks.

A study published in 2022 showed a direct relationship between human activities and the pollution of water bodies, confirming the physiological and histopathological impact of heavy metals such as iron, manganese, zinc, copper, cadmium, and lead on the Nile tilapia and assessing the potential risks to human health related to fish consumption from Lake Nasser.

The index of heavy metal accumulation was highest in the liver, followed by the gills, and then the muscles. This finding highlights the negative impact of heavy metals on fish health and the function of their internal organs. The bioaccumulation of metals in the muscles, gills, and liver tissues indicated that iron was the most accumulated metal, followed by zinc, copper, manganese, lead, and cadmium.

The study confirmed that consuming fish from Lake Nasser is safe, as the accumulation of heavy metals in the muscles of tilapia (the edible portion) fell within the limits permitted for human consumption. The risk index did not indicate any adverse health effects for ordinary or habitual consumers at any of the sampling sites.

But the study emphasised the importance of continuously assessing health risks associated with high rates of metal contamination in fish tissues to maintain the health of fish populations and consumers. Salaheddin said she is studying mitigation mechanisms in tilapia fish and working on enhancing these mechanisms through diet supplements or vaccination to improve fish resistance and alleviate the impact of pollutants on health and growth.

A second study conducted by the National Institute of Oceanography and Fisheries, entitled “Evaluation of Heavy Metal Contents and Potential Risks in Surface Water and Fish in Lake Qaroun, Egypt,” published in 2022, warned of “serious” health risks from ingesting tilapia from the lake and recommended that residents and fishermen in the studied area be aware of potential health risks through different pathways related to the lake’s heavy metal content.

It said that consideration should be given to avoiding the continued contamination of the lake through untreated sewage and agricultural wastewater. According to CAPMAS, the production of tilapia and most other types of fish from Lake Qaroun in 2021 was zero.

A study to assess the risks of metal pollution for tilapia fish around the four islands of the Nile published in 2022 recorded pathological tissue lesions in tilapia fish samples collected from polluted areas, saying that this is an “early warning” for the habitual consumers of tilapia, who may consume the fish two or three times a week to an average of six to 12 ounces per week.

Hanan Sayed Gaber, a professor at the National Institute of Oceanography and Fisheries, reported that high levels of pollution can cause the emergence of diseases and histological changes in fish, especially tilapia, in different water bodies. “Uncontrolled human activity has also caused the spread of some parasites that have affected the health and productivity of fish,” she added.

Gaber explained that pollution affects the reproductive organs of the tilapia fish, which leads to malfunctions in reproductive activity and a subsequent decrease in fecundity.

FISH FARMING: Fish farming ensures that tilapia is freely available in Egypt even with the decline in natural fisheries production and helps to keep the price of the fish within the reach of consumer budgets, said Emad Abu Sitta, 38, the owner of a fish farm in Lake Edko in Beheira governorate.

He said that the reason for the popularity of tilapia compared to other types of fish is that it is still the cheapest, with prices ranging between LE60 for small tilapia and LE80 for larger fish per kg in the markets. The prices of other freshwater fish such as mullet and tobar starts at LE100, while the prices of saltwater fish are also rising.

The prices of some types of saltwater fish such as Mussa, sea bream, and shrimp range between LE200 and LE400 per kg. Fish farms have a significant role to play in producing tilapia and keeping prices down.

However, fish farming does not necessarily mean reducing pollution. Salaheddin said. “The law does not allow the use of fresh water suitable for drinking for fish farming. Fish farms use agricultural drainage water, and the rate of water change is low, unlike in the natural environment where the fish can move away from sources of pollution. Running water also helps reduce the rate of pollution, unlike the closed systems used by fish farms.”

One expert on tilapia farming said that the fish are affected by the quality of the water. “We see this in the taste of fish that live in water polluted by agricultural or industrial waste, which cannot be compared to the taste of fish that are raised in high-quality water,” he said.

Tilapia fish are in their best condition and production is highest from April to November. It reaches its peak in July when the spawning season that extends from December to March has finished. It is then that the fish regain their vitality and become fatter and better tasting.

 Nasr Ahmed, an associate professor at the National Institute of Oceanography and Fisheries, says that tilapia are highly sought after by consumers because they are the most available and the lowest priced.

Fish in general are rich in vitamins and Omega-3 fatty acids that benefit the body and contribute to building muscles. Environmental laws related to the discharge of factories and service facilities into water bodies should be implemented, he said, and they should be subject to permanent monitoring. Penalties should be increased for violators to reduce pollution levels, Ahmed said.

Law 48/1982 on the Protection of the River Nile and Waterbodies from Pollution prohibits the disposal of all types of waste into waterways except with a licence from the Ministry of Irrigation. Article 4 of the executive regulations of the law stipulates that industrial waste discharged into waterways must not contain any chemical pesticides, radioactive materials, or floating materials, or any material that could constitute harm to humans, animals, fish, plants, or birds, or affect the suitability of water for drinking, or domestic, industrial, or agricultural purposes.

Article 6 of the regulations prohibits the discharge of liquid industrial waste or untreated sewage into waterways and groundwater reservoirs.

The law stipulates that the Ministry of Health and Population is assigned to analyse samples of treated liquid waste and report the results to the Ministry of Water Resources and Irrigation, accompanied by the opinion of Ministry of Health and Population laboratories. The ministry is supposed to conduct periodic analysis of samples of treated liquid waste from facilities licensed to discharge into waterways at least once every three months. In the event of a violation of the conditions, the license will be withdrawn.

Violators of the law can be punished by imprisonment for a period not exceeding one year and a fine of not less than LE500 and not more than LE2,000, or one of these two penalties.

Egypt has paid significant attention to developing its fish wealth in recent years through expanding fish farming and operations to improve efficiency. Work has also been done to clean and dredge canals. Egypt’s fish production increased from 1.4 million tons in 2014 to 2.3 million tons in 2021, according to CAPMAS.