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Technical note reignites debate on the classification of Nile tilapia

Editor/Mohamed shihab

A publication authored by 33 researchers compiles studies on the ecological risks posed by the species and aims to inform decisions made by Conabio.

A technical note signed by 33 Brazilian researchers addresses the classification of Nile tilapia (Oreochromis niloticus) as an invasive alien species. Published on June 29th in the scientific repository EcoEvoRxiv, the document compiles studies from the scientific literature that, according to the authors, indicate that the species meets the international criteria for this classification. The material was also prepared to contribute to ongoing discussions within the National Biodiversity Commission (Conabio).

The topic involves one of the main species in Brazilian aquaculture. In 2025, Brazil produced 707,495 tons of tilapia, a volume equivalent to about 70% of the national production of farmed fish. The species also accounted for approximately 94% of Brazilian fish farming exports, consolidating the country as the fourth largest tilapia producer in the world, according to the 2026 Brazilian Aquaculture Yearbook, from the Brazilian Aquaculture Association (Peixe BR). The same data are also found in Technical Note No. 2/2026 from Embrapa Fisheries and Aquaculture.

The technical note addresses the potential impacts of tilapia presence in natural environments outside their original range. According to the authors, the document aims to compile available scientific knowledge on the ecological aspects related to the species, without addressing its economic importance for fish farming.

According to Jean RS Vitule, professor at the Federal University of Paraná (UFPR) and senior author of the publication, the document seeks to provide scientific support for discussions on public policies and proposals related to the cultivation and legal classification of exotic species.

The authors also highlight that Brazil has the greatest diversity of freshwater fish in the world, with thousands of species distributed across different river basins, many of them endemic. According to the publication, the introduction of species outside their natural distribution is one of the factors analyzed by the scientific community in studies on changes in aquatic ecosystems.

The presence of tilapia in Brazil dates back to the 1950s. The rendalli tilapia (Coptodon rendalli) was introduced in 1953. The Nile tilapia, on the other hand, was officially introduced in 1971 by the then National Department of Works Against Drought (DNOCS), with the aim of producing fingerlings for stocking public reservoirs in the Northeast and increasing the supply of fish.

Characteristics such as rapid growth, good feed conversion, adaptability to different environmental conditions, and high reproductive potential have favored the expansion of Nile tilapia, which has become the main species in Brazilian fish farming.

According to the technical note, when individuals escape from fish farms, ponds, or net cages, manage to survive, reproduce, and form populations in natural environments, a process called biological invasion occurs. This is the central theme discussed by the researchers in the document.