Aquatic Invasive Species

Blackchin Tilapia (Sarotherodon melanotheron)

Description:

• Usually have black spots on chin or throat (Campbell 1987)
• Irregular vertical bars (Trewavas 1983)
• Gold spot near gills in males (Trewavas 1983)

Habitat:

• High salinity tolerance (Randall 1987) and prefers brackish water (Trewavas 1983)
• Found in streams, estuaries and wetlands (Englund 2005)

Impacts & Concern:

• Can greatly reduce aquatic vegetation present (Courtenay 1974) and therefore negatively impact native Hawaiian birds (McGuire 2006)
• May overcrowd (Courtenay 1974) or act aggressive towards native fish (Faunce and Paperno 1999)

• Could serve as a vector of disease: blackchin tilapia is impacted by an unknown disease sometimes with no symptoms (Mauel et al. 2003) as well as the bacterium Francisella noatunensis subsp. Orientalis (Yamasaki et al. 2022)

Introduction:

• Imported by Bureau of Commercial Fisheries in 1962 onto Sand Island where it was studied as potential tuna bait and likely escaped (Randall 1987)
• After initial escape, blackchin tilapia spread through freshwater and estuary habitats (Szyper et al. 2000)

Distribution in Hawaii:

• Kauai: Anahola Stream, Puali Stream (Yamasaki 2022)
• Oʻahu: Kahuku Pond, Kuliouou Steam, Kawaihāpai Reservoir (Yamasaki 2022), Wahiawa Lake, Nuʻuana Reservoir (Wu and Yang 2012)
• Molokai: Not documented
• Lanai: Not documented
• Maui: Not documented
• Big Island: Not documented

Related AIS Team Management Projects:

• 2019 Special Activity Permit allowed DAR officials and local fishermen to net about 300 fish in Nu‘alolo Bay, Kaua‘i
• DAR investigated a large die-off of tilapia in the ‘Anahulu River near Hale‘iwa, O‘ahu after reports from kayak/SUP rental companies
• Monitoring for spread and disease outbreaks continues

Regulations:

• Prohibited for import, not currently listed under HDOA import rules (§4-71-6.5)

References:

• Campbell, D. (1987). A review of the culture of Sarotherodon melanotheron in West Africa. UNDP-FAO-NIOMR. 20 p.
• Courtenay W.R., Sahlman H. F., Miley W. M., Herrema D. J. Exotic fishes in fresh and brackish waters of Florida. (1974). Biological Conservation, 6(4), 292-302. https://doi.org/10.1016/0006-3207(74)90008-1
• Englund, R.A. (2005). Threats to native aquatic insect biodiversity in Hawaiʻi and the Pacific, and challenges in their conservation. [Doctoral dissertation, University of Hawaiʻi]. University of Hawaiʻi Manoa ScholarSpace.
• Faunce, C.H. & Paperno R. (1999). Tilapia-dominated fish assemblages within an impounded mangrove ecosystem in east-central Florida. Wetlands, 19(1), 126-138.
• Mauel, M., Miller, D., Frazier, K., Liggett, A., & Styer, L., Montgomery-Brock, D., & Brock, J. (2003). Characterization of a piscirickettsiosis-like disease in Hawaiian tilapia. Diseases of aquatic organisms, 53, 249-55. 10.3354/dao053249
• McGuire, C. (2006). Effects of introduced fish on aquatic insect abundance: A case study of Hamakua marsh, Oahu Hawaiʻi. [Master dissertation, University of Hawaiʻi]. University of Hawaiʻi Manoa ScholarSpace.
• Randall, J. E. (1987). Introductions of marine fishes to the Hawaiian Islands. Bulletin of Marine Science, 41(2), 490-502.
• Szyper, J.P., Hopkins, K.D., Malchow, W., & Okamura, W. Y. (2000). History and Prospects of Tilapia Stocks in Hawaii, U.S.A. In Tilapia Culture in the 21st Century–Proceedings from the Fifth International Symposium on Tilapia Aquaculture, Rio de Janeiro, Brazil.
• Trewavas, E. (1983). Tilapiine Fishes of the genera Sarotherodon, Oreochromis, and Danakilia. The Dorset Press. https://doi.org/10.5962/bhl.title.123198
• Yamasaki L.S., Iwai T.,Klinger-Bowen R. C., Weese D.A., Fowler C.E., Yacoub J.L., & Wong M.A. (2022). Identification of Nile tilapia (Oreochromis niloticus) and its hybrids in natural environments in Hawaii. Aquaculture, 550, e737805. https://doi.org/10.1016/j.aquaculture.2021.737805