Cooperative Fish and Wildlife Research Units Program: Arizona
Education, Research and Technical Assistance for Managing Our Natural Resources

Endemic fishes of the arid southwestern United States have rapidly declined due to anthropogenic stressors. Identifying the habitat conditions needed by these species is critical for their successful management. Habitat suitability criteria are commonly used to conserve species of interest. Therefore, developing habitat suitability criteria for native fish species across multiple rivers permits better understanding of how different environments are occupied under various circumstances. We developed stream-specific and generalized criteria for Longfin Dace Agosia chrysogaster, Speckled Dace Rhinichthys osculus, and Desert Sucker Pantosteus clarki, across four central Arizona streams. Over 1,200 sites were sampled using pre-positioned electrofishing devices during the 2017 summer low-flow period to identify relationships among fish presence and habitat variables (depth, velocity, and substrate class). Optimal (central 50% of range used) and suitable (central 95% of range used) ranges within each habitat variable were calculated for each stream, based on the occurrence of each species. In general, Longfin Dace occupied depths of 9.00 – 54.75 cm (14.25 – 27.25 cm) velocities of 0.00 – 0.63 m/sec (0.11 – 0.31 m/sec), and substrate (modified Wentworth scale) of 0.5 – 4.3
(2.1 – 3.3). Speckled Dace occupied depths of 8.25 – 74.00 cm (17.00 – 34.25 cm) velocities of 0.00 – 0.74
m/sec (0.16 – 0.43 m/sec), and substrate of 0.0 – 4.5 (2.2 – 3.6). Desert Sucker occupied depths of 9.00 –
45.00 cm (15.25 – 25.00 cm) velocities of 0.09 – 0.72 m/sec (0.21 – 0.44 m/sec), and substrate of 1.0 – 4.6 (2.5 – 3.7). Generalized habitat suitability criteria for all three species were significantly (P<0.05) transferable with the exception of substrate class. Field work on this project was conducted spring and summer, 2017 and data analysis in fall 2018. Information was presented in a thesis. In 2019, an additional stream was surveyed, Fossil Creek, to improve the accuracy of general habitat suitability data for native desert fishes, and to develop habitat suitability indices for fishes in a travertine system. Results from this project are currently being prepared for a theses, and results from both projects are being submitted/prepared for publication. Partners include USFWS and USFS.