Ecological Risk Screening Summary - Spotted Metynnis (Metynnis maculatus) - Uncertain Risk

Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.

Spotted metynnis (Metynnis maculatus) is a freshwater fish native to the Amazon and Paraguay river basins in South America. M. maculatus is used in commercial fisheries and aquariums. While M. maculatus is considered invasive in several rivers and reservoirs where it has been introduced, studies supporting this characterization are lacking. Means of introduction for this species include introduction for sport fishing, and movement when reservoirs flood natural barriers to movement. This species is known to have high reproductive potential, and is highly abundant in several locations where it has been introduced. This suggests that there may be ecological and economic impacts, although this is not confirmed in the literature. Given the absence of scientific studies confirming harm to native species, the environment, the economy or human health, history of invasiveness is classified as none documented. The climate match for M. maculatus in the contiguous United States is medium, with highest matches in the Southeast and Southwest. There are no known introductions of this species in the United States, but members of the Metynnis genus (species uncertain) have been collected beyond their native range in Florida, where their status is listed as locally established. Certainty of assessment is low because of the lack of definitive impacts and the uncertain taxonomy of this genus. Overall risk for this species is Uncertain.