thumbnail

A quantitative life history of endangered humpback chub that spawn in the Little Colorado River: variation in movement, growth, and survival

Ecology and Evolution

By:
, , , and
DOI: 10.1002/ece3.990

Links

Abstract

While the ecology and evolution of partial migratory systems (defined broadly to include skip spawning) have been well studied, we are only beginning to understand how partial migratory populations are responding to ongoing environmental change. Environmental change can lead to differences in the fitness of residents and migrants, which could eventually lead to changes in the frequency of the strategies in the overall population. Here, we address questions concerning the life history of the endangered Gila cypha (humpback chub) in the regulated Colorado River and the unregulated tributary and primary spawning area, the Little Colorado River. We develop eight multistate models for the population based on three movement hypotheses, in which states are defined in terms of fish size classes and river locations. We fit these models to mark–recapture data collected in 2009–2012. We compare survival and growth estimates between the Colorado River and Little Colorado River and calculate abundances for all size classes. The best model supports the hypotheses that larger adults spawn more frequently than smaller adults, that there are residents in the spawning grounds, and that juveniles move out of the Little Colorado River in large numbers during the monsoon season (July–September). Monthly survival rates for G. cypha in the Colorado River are higher than in the Little Colorado River in all size classes; however, growth is slower. While the hypothetical life histories of life-long residents in the Little Colorado River and partial migrants spending most of its time in the Colorado River are very different, they lead to roughly similar fitness expectations when we used expected number of spawns as a proxy. However, more research is needed because our study period covers a period of years when conditions in the Colorado River for G. cypha are likely to have been better than has been typical over the last few decades.

Study Area

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
A quantitative life history of endangered humpback chub that spawn in the Little Colorado River: variation in movement, growth, and survival
Series title:
Ecology and Evolution
DOI:
10.1002/ece3.990
Volume
4
Issue:
7
Year Published:
2014
Language:
English
Publisher:
John Wiley & Sons Ltd.
Contributing office(s):
Southwest Biological Science Center
Description:
13 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Ecology and Evolution
First page:
1006
Last page:
1018
Country:
United States
Other Geospatial:
Colorado River;Little Colorado River