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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American eels Anguilla rostrata (yellow phase; N = 462) collected from brackish-water portions (range of salinity: 0-23ø/w) of the Cooper River, South Carolina, ranged in length from 26.0 to 68.7 cm and in weight from 32 to 767 g. The length-weight relationship is log•0W = -5.85 + 3.07 1og•0L; W = wet weight (g) and L = total length (mm). Age estimates (inland years) from 442 pairs of otoliths indicated a mean age of 4.3 years and range of 1-12 years. Growth of American eels from brackish-water areas of the Cooper River was faster than growth of the species from northeastern United States and Canada. American eels from this southern habitat appear to migrate back to sea after ages 6-7, sooner than eels from northern locations. Histological examination of gonads from 458 specimens revealed that females outnumbered males 23 to 1. These results were consistent with most previous investigations and suggest that females dominate American eel populations in brackish-water and freshwater habitats in North America. The American eel Anguilla rostrata is a catadromous species that is harvested in brackish and freshwater areas in South Carolina and other eastern-seaboard states (Lane 1978). Although age-and-growth information is available for American eels inhabiting fresh waters of South Carolina (Harrell and Loyacano 1982) and other locations farther north (Ogden 1970; Gray and Andrews 1971; Hurley 1972; Facey and LaBar 1981), similar data for brackish-water American eels are limited to Newfoundland