American Fisheries Society Crayfish of the United States and Canada

This is the second compilation of crayfishes of the United States and Canada prepared by the American Fisheries Society's Endangered Species Committee. Since the last revision in 1996, the number of crayfish taxa in need of conservation attention changed little. This list includes 363 taxa representing 12 genera and 2 families.

Approximately 48% of species or subspecies in the study area are imperiled. There are 54 vulnerable, 52 threatened, and 66 endangered extant taxa; 2 taxa are possibly extinct. For some crayfishes, limited natural range (e.g., one locality or one drainage system) precipitates recognition as Endangered or Threatened; but for many others, status assignments continue to be hampered by a paucity of recent distributional information.

While progress has been made in this arena, basic ecological and current distributional information are lacking for 60% of the U.S. and Canadian crayfish fauna. Threats highlighted in Taylor et al. (1996) such as habitat loss and introduction of nonindigenous crayfishes continue to persist and are greatly magnified by the limited distribution of many species. Recognition of the potential for rapid decimation of crayfish species, especially those with limited ranges, should provide impetus for proactive efforts toward conservation.

Maps: Each taxon on the list was assigned to one or more states or provinces that circumscribe its native distribution. Mapped distributions indicate where taxa naturally occur or occurred in the past. States or provinces with parentheses in text and tables are locations where taxa are known or suspected to be introduced.

A variety of sources were used to obtain distributional information, most notably Taylor et al. (1996) and multiple state-specific literature and websites.