Spatial and temporal patterns of nonindigenous fish introductions in the United States

In 1978 biologists in Gainesville, Florida, began compiling records on the distribution and status of nonindigenous fishes known in U.S. inland waters. The database, now in electronic format, currently contains approximately 17,000 records representing more than 500 nonindigenous fish taxa (i.e., species, hybrids, and unidentified forms). Of these taxa, 317 (61%) are native to the United States but have been introduced by humans into U.S. drainages outside their natural geographic ranges; 185 (35%) are fishes introduced from foreign countries; and 22 (4%) are hybrids. Of the introduced foreign fish taxa, 71 (38%) are species that have established (i.e., reproducing) or possibly established populations in open U.S. waters. The database is a useful tool for natural resource managers and other decision makers. Although we periodically revise records and constantly enter new ones, our database is fairly updated; thus, we are able to more thoroughly analyze patterns of introduction and the spread of nonindigenous fishes within the United States. Moreover, information gaps exposed by the data set should serve to stimulate and guide future research on nonindigenous fishes. This paper introduces our database and provides an overview of temporal and spatial patterns of nonindigenous fish distributions in U.S. inland waters.