Gila River Basin Native Fish Monitoring Annual Report 2018

This report summarizes monitoring activities conducted by Marsh & Associates, LLC (M&A) during calendar year 2018 for the Gila River Basin Native Fish Monitoring project (GRBMP). Here, detailed trip summaries with catch data are reported, results are summarized across sub-basins, species distribution maps were constructed, sampling gears were qualitatively evaluated, and a preliminary multivariate analysis of fish community composition was completed.

Surveys were conducted in selected streams of major drainages throughout Gila River basin that were not being surveyed by other entities (i.e., agencies, institutions, and private contractors). The focus species in each stream is one or more of five native species: Gila Chub Gila intermedia, Roundtail Chub Gila robusta, Spikedace Meda fulgida, Loach Minnow Tiaroga cobitis, and Gila Topminnow Poeciliopsis occidentalis. Gila Chub, Spikedace, Loach Minnow, and Gila Topminnow are currently listed as endangered. Roundtail Chub and Headwater Chub Gila nigra were historically recognized as separate species but were recently reclassified and combined as a single species referred to as Roundtail Chub (Page et al. 2017). Here, we refer to both chub as Roundtail Chub, and note streams where they formerly were recognized as Headwater Chub. Gila Chub also was merged with Roundtail Chub, but they are reported separately because they still are listed as an endangered species.