Status of Freshwater Fishes of the United States: Overview of an Imperiled Fauna

Abstract

Conservation biologists have begun a concerted effort to educate the public, resource administrators, and politicians about the decline of temperate ecosystems, including their fishes. The United States harbors the most diverse temperate freshwater fish fauna in the world with about 790 species represented, about 90% of which are nongame fishes. From a state‐by‐state perspective, diversity of fishes in the United States is concentrated in the South, primarily in Alabama, Kentucky, Georgia, Mississippi, Tennessee, and Virginia, each of which supports at least 200 native fish species. Endemicity of fishes is high in both the South and West; in the latter region, up to 70% of fishes in some drainages (e.g., Colorado River) are endemic. Imperilment apparently is not confined to particular taxonomic groups. Of the five most diverse fish families in the United States, total imperilment ranges from 7% in the Centrarchidae to 50% in nonanadromous salmonids and indicates widespread and pervasive degradation of aquatic habitats. Imperilment is most acute in areas of high diversity and/or endemicity (i.e., the southern and western states). States with 20 or more imperiled fishes include Alabama, Arizona, California, Georgia, Nevada, New Mexico, North Carolina, Oregon, Virginia, Tennessee, and Texas. Backlogs in listing species as federally threatened or endangered are most egregious (10 or more backlogged taxa) in Alabama, Georgia, Nevada, and Tennessee.

Species Richness and Patterns of Invasion in Plants, Birds, and Fishes in the United States*

“…Native fish species were prominent in the drainages of the Mississippi River (Figure 2g). High endemic areas of freshwater fishes also coincide with the unique geologic history of the southern Appalachians (Williams et al 1989;Warren and Burr 1994). Likewise, California has an overwhelming abundance of total species and endemic species (Dobson et al 1997), in part due to its unique paleo-biogeography (Stebbins and Major 1965), high habitat heterogeneity, large area, and abundant soil and water resources in many areas (see Stein et al 2000).…”

A Gap Analysis and Comprehensive Conservation Strategy for Riverine Ecosystems of Missouri

“…Ten percent of all the freshwater fish species, 30% of all the freshwater mussels, and 61% of all the freshwater crayfish that have been described worldwide occur in the United States (Page and Burr 1991, Williams et al 1993, Warren and Burr 1994, Taylor et al 1996, Master et al 1998. Even more impressive statistics have been reported for other freshwater taxa (e.g., stoneflies, dragonflies, mayflies; Master et al 1998).…”

“…In the last one hundred years 123 freshwater animals have gone extinct in North America (Ricciardi and Rasmussen 1999). In the United States alone, 71% of freshwater mussels, 51% 1 E-mail: sowasp@missouri.edu of freshwater crayfish, and 37% of freshwater fish are currently considered vulnerable to extinction (Williams et al 1993, Warren and Burr 1994, Taylor et al 1996, Master et al 1998. Perhaps even more alarming are predictions by Riccardi and Rasmussen (1999) who, by using extinction records and an exponential decay model, found extinction rates of freshwater fauna in North America to be 5 times higher than those of terrestrial fauna.…”

Ozark-Ouachita Highlands Assessment: Aquatic Conditions

“…The Ozark-Ouachita Highlands are part of a region-the Southern United States plus the Missouri Ozarks-that harbors the richest freshwater fish fauna on the North American continent (Warren and Burr 1994). The Highlands' streams and rivers alone are home to at least 190 native fish species, representing 51 percent of the native freshwater fishes of the entire Mississippi River Basin, about 24 percent of those of the Continental United States, and 18 percent of all native freshwater fishes of North America Mayden 1992, Warren andBurr 1994).…”