Invasive Tilapia Species Spread Across Five Continents, Prompts Research on Detection Methods

Strategic Insights -

According to researchers at the Shanghai Ocean University, tilapia, native to Africa, have been introduced to aquaculture and the ornamental fish trade, leading to their spread across five continents. This spread has made them one of the most ecologically harmful invasive species. A study published in the journal NeoBiota used environmental DNA (eDNA) methods to monitor tilapia invasion, finding that previously designed universal primers were not sensitive enough for detection.

Key Takeaways:

  • Tilapia, originally from Africa, have spread to five continents due to human introductions for aquaculture and the ornamental fish trade.
  • Traditional fish survey methods are often ineffective in detecting tilapia during the early stages of their escape.
  • Researchers designed four pairs of tilapia-specific primers for use in multiplex PCR coupled with high-throughput sequencing, enabling the simultaneous detection of multiple tilapia species in a single reaction.
  • The designed primers exhibited higher detection sensitivity than universal primers, reaching a detection limit of 5.33 x 10^-7 ng/L.
  • Multi-locus amplification achieved a 95% limit of detection (LOD) at 2.66 x 10^-6 ng/L, significantly better than single-locus amplification.
  • Water samples collected from nine rivers across four drainages in China revealed the presence of tilapia in rivers such as the Yangtze River and the Pearl River.
  • The study detected Oreochromis niloticus and Coptodon zillii as the dominant invasive species, with some locations also showing the presence of O. aureus and Sarotherodon galilaeus.
  • This method provides an effective tool for early monitoring of tilapia invasion, inspiring the development of similar strategies for monitoring other invasive species.

Statistics:

  • The study used four pairs of tilapia-specific primers for use in multiplex PCR coupled with high-throughput sequencing.
  • The designed primers exhibited a detection limit of 5.33 x 10^-7 ng/L.
  • Multi-locus amplification achieved a 95% limit of detection (LOD) at 2.66 x 10^-6 ng/L.
  • Water samples were collected from nine rivers across four drainages in China.
  • The study detected Oreochromis niloticus and Coptodon zillii as the dominant invasive species.
  • The study found the presence of O. aureus and Sarotherodon galilaeus in some locations.

Sources:

  • NeoBiota. "Multi-locus environmental DNA markers and taxon-specific primers enhanced detection rate of invasive tilapia." 2025,101():185-202. (NeoBiota - http://neobiota.pensoft.net/).
  • Pensoft Publishers. "NeoBiota." (publisher).
  • NewsRx. "Shanghai Ocean University Researchers Further Understanding of Invasive Species (Multi-locus environmental DNA markers and taxon-specific primers enhanced detection rate of invasive tilapia)." Life Science Weekly. October 21, 2025; p 6685.