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  • County assists with release of Gila topminnow

    May 09, 2019 | Read More News
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    When County officials and Arizona Game and Fish biologists released 542 Gila topminnow into Edgar Canyon April 19, it marked the first introduction of species under an almost-finalized Aquatic Species Management Plan.

    “What really drove the process though,” said Brian Powell, assistant division manager for Pima County Natural Resources, Parks and Recreation, “was the County’s Sonoran Desert Conservation Plan and Multi-species Conservation Plan.” 

    The SDCP balances the conservation and protection of cultural and natural resource heritage with efforts to maintain an economically vigorous and fiscally responsible community. The MSCP is the part of the SDCP that deals with compliance with the Endangered Species Act.
    Release of Gila topminnow
    The Gila topminnow (Poeciliopsis occidentalis) is a small (1-2 inch) guppy-like fish native to the greater Gila River watershed in Arizona, New Mexico, and northern Sonora, Mexico. They prefer smaller creeks and streams with pools and eddies for shelter. Topminnow are the same family as guppies, which bear live young rather than lay eggs.

    In southern Arizona, the topminnow is native to the Santa Cruz and San Pedro River watersheds, however they now only occur in a few specific locations in Pima County, including Cienega Creek, Sabino Canyon, and the lower Santa Cruz River.

    Powell and Marisa Rice, a program manager with Pima County Regional Flood Control District, were on hand for the translocation of the Gila topminnow, once one of the most widespread fish species in lower elevation streams in the Gila River basin. 

    Now, explained Tony Robinson with Arizona Game & Fish, the Gila topminnow are listed as endangered because their distribution drastically shrank due to negative interactions with nonnative fish species and loss of habitat as a result of dams, diversions, and water pumping. That’s why Arizona Game and Fish Department has partnered with Pima County to recover Gila topminnow. 

    “To achieve recovery, new populations need to be established in the species historic range, and new and existing populations need to be protected from threats,” Robinson said. “Hopefully Gila topminnow will establish in Edgar Canyon and thus bring the species closer to recovery, downlisting and delisting. Recovery is possible in the near future.”
    Edgar Canyon is a major tributary leading to the San Pedro River. Near the canyon sits Six Bar Ranch, purchased by Pima County in 2006 for the purpose of protecting a diversity of wildlife and continuing the historic southern Arizona practice of cattle ranching. 

    The SDCP has a significant focus on riparian and aquatic resources. Protection of water resources was a driver of Pima County’s most recent and significant land acquisition program, which began in 2005 with voter-approved bonds and other funding sources. Today, the County and its Regional Flood Control District own over 107,000 acres of fee lands and hold over 143,000 acres of state and federal grazing leases. Important water resources can be found throughout these County conservation lands.