Oreochromis aureus

“The blue tilapia is considered a competitor with native species for spawning areas, food, and space (Buntz and Manooch 1969; Noble and Germany 1986; Muoneke 1988; Zale and Gregory 1990). Courtenay and Robins (1973) reported that certain streams where this species is abundant have lost most vegetation and nearly all native fishes. It has invaded the Taylor Slough portion of Everglades National Park where it is considered a major management problem for the National Park Service (Courtenay 1989; Courtenay and Williams 1992).\"

Stomach content analyses of blue tilapias in this region obtained by the US Geological Survey indicate that they are omnivorous, feeding on a range of vegetable and animal material, including fish (USFWS, 2002).

\"Blue tilapias (O. aureus) were discovered in Muddy River, southern Nevada, in 1992 as a result of an illegal introduction. By 1996, they had dispersed throughout the river. In 1994, they were found in two basins of Lake Mead, and have since been found throughout the lake. By 2001 it was determined that they had spawned in the Virgin River (USFWS, 2002). The decline in the number of endangered Moapa dace (Moapa coriacea) and Moapa White River springfish (Crenichthys baileyi moapae) have been correlated with the presence of tilapia. Tilapias are believed to prey on, or compete with, other native fish such as the federally endangered woundfin (Plagopterus argentissimus) and Virgin River chub (Gila seminude) (USFWS, 2002).\"; “Blue tilapia have also been implicated as the cause for unionid mussel declines in two Texas water bodies, Tradinghouse Creek and Fairfield reservoirs (Howells 1995).”

\"The 1st known introduction of blue tilapia in Nevada was in the Muddy River (a.k.a. Moapa River), Clark County, Nevada, and its arrival was followed by a decline in populations of native fishes (Scoppettone et al. 1998)\"; \"The blue tilapia's local abundance and high densities in certain areas have resulted in marked changes in fish community structure (Muoneke 1988, and citations therein). A dramatic reduction in native fishes in the Warm Springs area of Nevada coincided with invasion of this species (Scoppettone et al. 1998, 2005).”