In 2004, the Department, U.S. Forest Service, U.S. Bureau of Reclamation, U.S. Fish and Wildlife Service, Arizona Public Service, and Northern Arizona University staff began efforts to restore Fossil Creek as a refuge for native fish. The first phase of the project involved the decommissioning of the local power plant (which diverted much of Fossil Creek’s water into a flume system), the construction of a fish barrier, and chemical removal of non-native fish from the stream. Headwater/Roundtail Chub, Sonora Sucker, Desert Sucker, Speckled Dace, and Longfin Dace were salvaged from Fossil Creek prior to the chemical treatment and restocked after its completion. Post-treatment monitoring found that native fish populations increased dramatically following the removal of non-native fish and the restoration of stream flows. The Department, in coordination with the Fossil Creek Working Group, then began reintroducing five species of native fish into the creek, including Spikedace, Loach Minnow, Razorback Sucker, Gila Topminnow, and Longfin Dace. Four of these species are federally listed as endangered under the Endangered Species Act.
Between 2007 and 2014, Spikedace, Loach Minnow, Razorback Sucker, Gila Topminnow, and Longfin Dace were stocked multiple times in Fossil Creek. The goal of these stocking efforts, with the exception of Razorback Sucker, was to establish self-sustaining populations of each species within Fossil Creek. For Razorback Sucker, the goal was for juvenile fish to rear in Fossil Creek and then disperse downstream into the Verde River. As with any native species introduction, post-stocking monitoring is essential to determine whether or not these goals have been attained and to determine if additional stockings should be continued. In Fossil Creek, monitoring techniques varied across species and included backpack electrofishing, snorkeling, and trapping.
During the summer of 2016, the Department and U.S. Bureau of Reclamation staff completed the final post-stocking monitoring surveys for the five reintroduced native fish species. Based on these surveys, Spikedace, Gila Topminnow, and Longfin Dace have established self-sustaining populations in Fossil Creek. This is positive news for Spikedace recovery as they are currently restricted to only one naturally occurring population in Arizona. Unfortunately, Razorback Sucker and Loach Minnow failed to establish populations in Fossil Creek despite intense reintroduction efforts. Spikedace, Gila Topminnow, and Longfin dace populations will continue to be monitored in Fossil Creek, likely at less frequent intervals, in order to determine future management needs.
We would like to thank everyone involved in the Fossil Creek Native Fish Restoration Project. Due to the efforts of multiple agencies, universities, non-governmental organizations, volunteers, and other partners, Fossil Creek is one of the most unique streams in Arizona because of the high diversity of native fish species. We would like to recognize the Department’s Region II (Flagstaff) Aquatic Wildlife staff that has also been instrumental in managing and monitoring Fossil Creek’s native fish populations. Whereas the Department’s Native Aquatic Program was responsible for species reintroduction efforts in Fossil Creek and their subsequent monitoring, Region II annually monitors native chub, sucker, and dace populations in Fossil Creek and ensures that the stream remains non-native fish free. Region II also led a second chemical treatment of Fossil Creek in 2012, following the detection of Smallmouth Bass above the barrier.
Kent Mosher, Native Aquatics Program