Little Colorado River (LCR) Projects

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Project Descriptions Spring and Fall LCR surveys (4 trips/yr) [1] The LCR is divided into three contiguous reaches (Boulders, Coyote, and Salt) Uses hoopneting in the lower 13.57 river kilometers of the LCR to generate marks and get recaptures Closed Chapman Petersen mark-recapture to estimate absolute abundance of ≥150 mm and ≥200 mm humpback chub (spring and fall) and age-0 humpback chub (40-99 mm) in the fall. Catch per unit effort (CPUE) data = estimate relative abundance The two spring mark-recapture efforts (generally during April and May) are aimed to coincide with the peak of humpback chub spawning in the LCR and provides an annual estimate of the spring spawning abundance. The two fall mark-recapture efforts (generally during September and October) temporally expand marks and recaptures of humpback chub in the LCR, thereby strengthening other open or multistate models. Humpback chub, flannelmouth sucker, and bluehead sucker >150 mm are PIT tagged. From 2010 onward, humpback chub 40-99 mm received a Visible Implant Elastomer (VIE) tag Humpback chub and other fish were visually checked for the presence of the external copepod parasite (Lernaea cyprinacea), but the internal Asian fish tapeworm (Bothriocephalus acheilognathi) is no longer monitored. Juvenile Chub Monitoring (JCM) Near Shore Ecology (NSE) Study of the 2009-2011 fall steady flow test LCR PIT tag array Migration timing [2]

Links and Information The Humpback Chub Page Presentations and Papers 2017 Mark-Recapture and Fish Monitoring Activities in the Little Colorado River in Grand Canyon from 2000 to 2016 Humpback Chub that Spawn in the LCR: Status and Drivers 2016 Spring 2016 Lower LCR humpback chub sampling trip report Mark-Recapture and Fish Monitoring Activities in the Little Colorado River in Grand Canyon Colorado River in Grand Canyon from 2000 to 2015 Humpback chub (Gila cypha) that Spawn in the Little Colorado River: Status and Potential Drivers 2013 An Overview of Humpback Chub Monitoring in the Little Colorado River Other Stuff Adult chub: >200mm Subadult chub: 150-199mm Juvenile chub: <150mm Catch per unit effort (CPUE): courser measure that can show trends in abundance