Rudd (Scardinius erythrophthalmus) is a member of the minnow family and is native to western Europe. It was first brought into the United States in the late 1800s or early 1900s with a second group of introductions in the late 1960s and early 1970s. Rudd have been present in New York's Roeliff-Jansen Kill drainage since the early 1900s. Rudd have been established in
Lake Cobboseecontee, Maine, since 1973. As of 2005, the Nonindigenous Aquatic Species Program in Gainesville, Florida, reported rudd from 22 states, with reproducing populations established in Massachusetts, Maine, Missouri, Nebraska, New York, Virginia, Washington, and Wisconsin. The species has been widely reported in Colorado but we do not know whether populations are established there or not.
Like many of the smaller and lesser known exotic species, we know relatively little about the potential impacts of Rudd on native fishes and aquatic habitats but we have reason to believe that their presence is cause for concern. They have been reported to hybridize with native minnows. They also are suspected to compete with native fishes, including trout, for foods such as aquatic insects.
Rudd have been imported into this country as a baitfish. They are propagated in Arkansas and Virginia and distributed to bait shops in as many as 16 states. Bait bucket releases, often illegal, appear to be the primary way by which they reach new habitats. Rudd tolerate a wide variety of conditions and have been found in a number of habitats from subalpine lakes to large rivers and small streams. They are reported to feed mostly on aquatic invertebrates but also can switch to plant foods. In at least certain habitats, Rudd can live up to 30 years.
Source: Schofield, P.J., J.D. Williams, L.G. Nico, P. Fuller, and M.R. Thomas. 2005. Foreign nonindigenous carps and minnows (Cyprinidae) in the United States - a guide to their identification, distribution, and biology: U.S. Geological Survey Scientific Investigations Report 2005-5041.