Galapagos Species Database

Taxon category: Accepted

Origin: Introduced - not established

Year of first record: 2006

Year of introduction: 2006

Mode of introduction: Intentional

Introduction Pathway: Intentional

Subpathway: Fishery in the wild

Introduced status: Eradicated

Impact in Galapagos: In Galapagos, no freshwater fish exist naturally in El Junco, and the addition of tilapia changed the composition and abundance of the lake's native aquatic community which contains endemic invertebrates. There was also worry that tilapia could spread from the lake to other inland and coastal sites.

Impact elsewhere: Tilapia overcrowd freshwater habitats and often show competitive behaviour to native species. Their most devastating impact is in Lake Victoria when its introduction, along with the Nile perch, has caused the extinction of 200 species of the endemic cichlid species. The adults' diet of algae has led to their use to control aquatic weeds.

Control History in Galapagos: The National Park Service and the USGS carried out an eradication campaign in El Junco using rotenone. This poison is made using rotenoid plant extract, and affects only cold-blooded organisms. Following a risk assessment, and removal of native invertebrates from the lake, rotenone was applied on 25 January 2008. This resulted in the death of 40,000 tilapia. After the rotenone had degraded, captive invertebrates were released back to the lake. Regular monitoring is needed to ensure that El Junco remains free of tilapia (it is also possible that it could be reintroduced).

Control methods elsewhere: A number of control methods exist including, manual removal by fishing, chemical control, genetic modification, use of hormones to change the sex of the population and biological control through release of a natural predator or parasite.

Known Pest elsewhere: Widespread

Habitat preferences: A tropical freshwater to brackish water species. Prefers water between 31-36 degrees Celsius but can survive temperatures from 12-42 degrees Celsius. Prefers shallow water.

Trophic role: Omnivorous

Reproduction mode: Exclusively sexual

Reproductive biology: Black Tilapia grow quickly and breed in their first year. Both parents tend the eggs and young in their mouth.

Distribution origin: North Africa, Nile River region

Map of specimen collection localities or observation records for this species in our collections database.

Distribution: Restricted to El Junco, San Cristóbal Island

• Appeltans, W. Bouchet, P., Boxshall, G.A., Fauchald, K., Gordon, D.P., Hoeksema, B.W., Poore, G.C.B., van Soest, R.W.M., Stöhr, S., Walter, T.C., Costello, M.J. (eds.) (2010) World Register of Marine Species (WoRMS). Available online at http://www.marinespecies.org.
• IUCN (2023) The IUCN Red List of Threatened Species. Version 2022-2 Https://www.iucnredlist.org
• Jiménez-Uzcátegui, G. Carrión, V., Zabala, J., Buitrón, P. & Milstead, B. (2007) Status of introduced vertebrates in Galapagos. Galapagos Report 2006–2007. Charles Darwin Foundation, Puerto Ayora, p. 136–141.
• Phillips, R. B. D.A. Wiedenfeld and H.L. Snell (2012) Current status of alien vertebrates in the Galápagos Islands: invasion history, distribution, and potential impacts. Biol Invasions (2012) 14:461–480 DOI 10.1007/s10530-011-0090-z
• Toral, V. Poulsom, T. (2006) La tilapia Oreochromis niloticus en la Laguna de El Junco, San Cristóbal. Informe técnico para la Fundación Charles Darwin y Servicio Parque Nacional Galápagos. Puerto Ayora, Ecuador. 5 pp.