The American Fisheries Society Endangered Species Committee herein provides a list of all crayfishes (families Astacidae and Cambaridae) in the United States and Canada that includes common names; state and provincial distributions; a comprehensive review of the conservation status of all taxa; and references on biology, conservation, and distribution. The list includes 363 native crayfishes, of which 2 (⟨ 1%) taxa are listed as Endangered, Possibly Extinct, 66 (18.2%) are Endangered, 52 (14.3%) are Threatened, 54 (14–9%) are Vulnerable, and 189 (52.1%) are Currently Stable. Limited natural range continues to be the primary factor responsible for the noted imperilment of crayfishes; other threats include the introduction of nonindigenous crayfishes and habitat alteration. While progress has been made in recognizing the plight of crayfishes, much work is still needed.

Rates of biodiversity loss are higher in freshwater ecosystems than in most terrestrial or marine ecosystems, making freshwater conservation a priority. However, prioritization methods are impeded by insufficient knowledge on the distribution and conservation status of freshwater taxa, particularly invertebrates. We evaluated the extinction risk of the world's 590 freshwater crayfish species using the IUCN Categories and Criteria and found 32% of all species are threatened with extinction. The level of extinction risk differed between families, with proportionally more threatened species in the Parastacidae and Astacidae than in the Cambaridae. Four described species were Extinct and 21% were assessed as Data Deficient. There was geographical variation in the dominant threats affecting the main centres of crayfish diversity. The majority of threatened US and Mexican species face threats associated with urban development, pollution, damming and water management. Conversely, the majority of Australian threatened species are affected by climate change, harvesting, agriculture and invasive species. Only a small proportion of crayfish are found within the boundaries of protected areas, suggesting that alternative means of long-term protection will be required. Our study highlights many of the significant challenges yet to come for freshwater biodiversity unless conservation planning shifts from a reactive to proactive approach.

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