By Garry Rogers

Arizona Fish Habitat

Small stretches of the Agua Fria River in central Arizona are perennial. The water is polluted by farm fertilizer and mine tailings. Invasive species are abundant.

The U. S. State of Arizona occupies a dry region with limited precipitation, high evaporation, and not much surface water.  Widespread winter rain and snow, and heavy summer rain can escape evaporation by penetrating the soil and accumulating in fractured rocks and sediments on slopes and in valley floors.  The moisture soaks down slope through the sediments, and appears in springs, intermittent streams, and a few perennial streams and small lakes.  Many isolated endemic and rare species are present in these small moist habitats across the state.  (The header image is a Beautiful Shiner (Cyprinella formosa) photographed by René Reyes of the U. S. Bureau of Reclamation.)

During the past century, the human population grew from thousands to millions.  First farming, and then industrial and urban users diverted the streams into reservoirs and then began withdrawing stored water in the ground.  Some stream segments and many springs have been lost.  The remaining surface water is declining and is being polluted with toxic residue from mines, towns, and farms.

The threatening situation facing Arizona fish is common worldwide.  According to Stephen J. Walsh, Howard L. Jelks, and Noel M. Burkhead of the U. S. Geological Survey, almost half of North American species are imperiled and the number is growing (2009 article online at Actionbioscience).

Arizona Fish Numbers

According to the October 10 report by the Arizona Game and Fish Department (AZGFD), there are 42 surviving native Arizona fish species.  Two native species are already extinct, and the rest are all considered vulnerable.  The numbers below are from the North American Native Fishes Association (NANFA), U. S. Fish and Wildlife Service, and the Arizona Game and Fish Department (AZGFD).  Percentages are given for Arizona’s native species.  Many of the introduced species are declining along with the natives.

• North America:  1200
• Arizona fish species:  42
• Arizona fish extinct:  2 (5%)
• Arizona fish vulnerable:  40 (100%)
• Arizona introduced exotic fish species:  68
• ESA Arizona fish Listed Endangered:  6 (15%)
• ESA Arizona fish Listed Threatened:  6 (15%)
• ESA Arizona fish of Concern:  2 (5%)

Arizona Fish References

• The online Naturalist’s Bookstore has field guides (at the end of the category list) and other references.  Go to:  http://bit.ly/RKW2bC.
• AZGFD, Arizona Game and Fish Department:  http://www.azgfd.gov.
• ASIH, American Society of Ichthyologists and Herpetologists:  http://asih.org.
• Burkhead, N. M.  2012.  Extinction rates in North American freshwater fishes, 1900-2010.  BioScience, 62: 798 – 808
• Miller, R.R.  1961.  Man and the changing fish fauna of the American Southwest.  Papers of the Michigan Academy of Science, Arts, and Letters 46: 365-404.
• Miller, R. R., and C.H. Lowe. 1964. Fishes of Arizona. Pages 133-151 in Lowe, C.H., Ed. The vertebrates of Arizona. University of AZ Press, Tucson. 270 p.
• Nelson J.S., E.J. Crossman, H. Espinosa-Pérez, L.T. Findley, C.R. Gilbert, R.N. Lea, and J.D. Williams.  2004.  Common and scientific names of fishes from the United States, Canada, and Mexico, 6th ed. American Fisheries Society, Bethesda, MD.  386 p.
• NANFA, North American Native Fishes Association:  http://www.nanfa.org.
• Smithsonian National Museum of Natural History.  Department of Vertebrate Zoology, Division of Fishes:  http://vertebrates.si.edu/fishes/
• Turner, D.S. and M.D. List.  2007.  Habitat mapping and conservation analysis to identify critical streams for Arizona’s native fish.  Aquatic Conservation: Marine and Freshwater Ecosystems 17:  737-748.
• U. S. Fish and Wildlife Service:  http://www.fws.gov.

Conservation Status Symbol Definitions (from AZGFD)

Symbols used by Arizona Game and Fish Department (AZGFD)

• S1         Critically Imperiled: Extremely rare or some factor(s) is making the species especially vulnerable to extirpation.  Typically 5 or fewer locations or very few remaining individuals (<1,000).
• S2         Imperiled:  Rare or some factor(s) is making the species very vulnerable to extirpation. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000).
• S3         Vulnerable:  Rare or found only in a restricted range (even if abundant at some locations), or because of other factors making it vulnerable to extirpation.  Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals.
• S4         Apparently Secure:  Uncommon but not rare, and usually widespread.  Usually more than 100 occurrences* and more than 10,000 individuals.  Possible long-term concern.
• S5         Secure:  Common, widespread, and abundant.  Safe under present conditions.  Typically with considerably more than 100 locations and more than 10,000 individuals.
• SH         Possibly Extirpated (Historical): Historically present, and there is some expectation that the species may be rediscovered.
• SX         Presumed Extinct:  Not located despite intensive searches of historical sites and other appropriate habitat, and virtually no likelihood that it will be rediscovered.
• S#S#:   Indicates the range of uncertainty about exact status (e.g., S3S4).
• E:          Exotic Origin:  Species is not native to AZ.

Symbols Used for the Endangered Species Act (ESA)
(US Department of Interior, Fish and Wildlife Service)

• LE         Listed Endangered:  Imminent jeopardy of extinction.
• LT         Listed Threatened:  Imminent jeopardy of becoming Endangered.
• XN        Experimental Nonessential population.
• PDL      Proposed for delisting.
• No        (No Status) Certain populations of this taxon do not have designated status (check with state or regional USFWS office for details about which populations have designated status).
• PE         Proposed Endangered
• C           Candidate:  Species for which the USFWS has on file sufficient information on biological vulnerability and threats to support proposals to list as Endangered or Threatened under ESA. Proposed rules for these species is precluded at present by other higher priority listing actions.
• C*         The Service identifies species for which they made a continued warranted-but-precluded finding on a resubmitted petition by the code “C*” in the category column.
• SC         Species of Concern:  Describes the entire realm of taxa whose conservation status may be of concern to the US Fish and Wildlife Service, but does not have official federal status.