Survival, growth, and movement of subadult humpback chub, Gila cypha, in the Little Colorado River, Arizona

River Research and Applications
By: , and 

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Abstract

Ecologists estimate vital rates, such as growth and survival, to better understand population dynamics and identify sensitive life history parameters for species or populations of concern. Here, we assess spatiotemporal variation in growth, movement, density, and survival of subadult humpback chub living in the Little Colorado River, Grand Canyon, AZ from 2001–2002 and 2009–2013. We divided the Little Colorado River into three reaches and used a multistate mark-recapture model to determine rates of movement and differences in survival and density between sites for different cohorts. Additionally, site-specific and year-specific effects on growth were evaluated using a linear model. Results indicate that summer growth was higher for upstream sites compared with downstream sites. In contrast, there was not a consistent spatial pattern across years in winter growth; however, river-wide winter growth was negatively related to the duration of floods from 1 October to 15 May. Apparent survival was estimated to be lower at the most downstream site compared with the upstream sites; however, this could be because in part of increased emigration into the Colorado River at downstream sites. Furthermore, the 2010 cohort (i.e. fish that are age 1 in 2010) exhibited high apparent survival relative to other years. Movement between reaches varied with year, and some years exhibited preferential upstream displacement. Improving understanding of spatiotemporal effects on age 1 humpback chub survival can help inform current management efforts to translocate humpback chub into new locations and give us a better understanding of the factors that may limit this tributary's carrying capacity for humpback chub.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Survival, growth, and movement of subadult humpback chub, Gila cypha, in the Little Colorado River, Arizona
Series title River Research and Applications
DOI 10.1002/rra.2864
Volume 32
Issue 3
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) Southwest Biological Science Center
Description 10 p.
First page 373
Last page 382
Country United States
State Arizona
Other Geospatial Little Colorado River
Online Only (Y/N) N
Additional Online Files (Y/N) N