The environmentalists’ concerns for tilapia farming is nothing new as the topic is being debated over the past few decades across the globe. However, the recent controversial decisions made regarding farming and importing tilapia in and to Iran has turned it into hot topic in Iran’s environmental circles.

What is tilapia?

Tilapia is the common name for nearly a hundred species of cichlid fish. Native to lakes in Africa, tilapia is mainly freshwater fish residing in shallow streams, ponds, rivers and lakes.

This versatile warm-water fish is known in the food business as “aquatic chicken” because of its easy breeding and bland taste. Tilapia happily eats pellets made largely of corn and soy and gains weight rapidly, easily converting a diet that resembles cheap chicken feed into low-cost seafood.

As far as nutritional value of this species is concerned, it should be said that like all other fish, tilapia is a good source of protein, with few of the unhealthy saturated fats in red meats.

However, it contains lower omega-3 fatty acids comparing to other fish in the market. While a portion of tilapia has 135 milligrams of omega-3 fatty acids, a portion of salmon has over 2,000 milligrams. And farmed tilapia may have even less than wild tilapia because fish acquire omega-3s by eating aquatic plants and other fish.

Also, the amount of omega-6 acids in tilapia outnumbers the beneficial omega-3s by a factor of 2 to 1, which some nutrition experts believe that this ratio can increase the risk of heart disease.

The environmental side

Generally, fish farms are notorious for having adverse effects on the environment because if the farm fish escape their pens, water pollution and spread of disease to wild fish can be expected and tilapia is not an exception.

Tilapia is one of the most invasive species known and it’s really hard to get rid of them once they are established. The aggressive breeding and feeding of the fish can squeeze out native fish and plant species in lakes, hence, they are considered a true danger for ecosystems.

The case of Lake Apoyo in Nicaragua

“One small cage screwed up the entire lake — the entire lake!” highlights Jeffrey K. McCrary in a paper published in 2007 in the Environmental Biology of Fishes journal.  He has spent many years studying how a small, short-lived tilapia farm degraded Lake Apoyo in Nicaragua.

Waste from the cages polluted the pristine ecosystem, and some tilapia escaped. An aquatic plant called charra, an important food for fish, disappeared, leaving the lake a wasteland. Some species of plants and fish are slowly recovering, but others are probably gone forever, said McCrary.