Various types of catfish, cavefish, chubs and dace qualify as endangered and are on the United States Fish and Wildlife Service list. Darters, madtoms, minnows and gambusias such as the Pecos gambusia also meet the criteria of an endangered fish species. An assortment of different pupfish, salmon, steelhead, sturgeon, trout and suckers comprise a large portion of the list.
The Oregon chub is a typical endangered endemic fish species. It made the endangered list of the United States Fish and Wildlife Service on Oct. 18, 1993 due to a number of reasons. A small olive-colored minnow that lives in the Willamette River Valley in the western portion of Oregon, this fish would benefit greatly when the river flooded. The flooding would create new areas for the fish to live and begin new populations. However, the river became subject to flood-control dams that took their toll on the Oregon chub. The introduction of fish such as bass precipitated problems as they fed on the chub. Such dangers as pesticides and chemical spills have also polluted its environment.
Fish that are on some states' endangered species lists are not necessarily on others. For example, the burbot, the American brook lamprey and the shortnose sturgeon qualify as endangered in Connecticut. The sturgeon is on federal endangered lists but the other two thrive in other parts of the country.
The white sturgeon, categorized as endangered since 1994, is the largest freshwater fish in North America. It is an example of a once widely distributed fish that now occupies a fraction of its former range. It has the ability to reach fantastic sizes, with some specimens weighing in at 1,800 pounds. In addition, this fish sometimes lives for more than a century. However, its river environment has felt severe impact from hydroelectric dams, pollution, the introduction of non-native species and changes in water flows. These have proved too much for the white sturgeon to overcome. It is illegal to fish for white sturgeon in every state. A comprehensive recovery effort that includes such initiatives as habitat restoration may or may not succeed in restoring the fish to its former numbers.