Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Rainbow trout (Oncorhynchus mykiss) have been purposely introduced in many regulated rivers, with inadvertent consequences on native fishes. We describe how trout growth rates and condition could be influencing trout population dynamics in a 130 km section of the Colorado River below Glen Canyon Dam based on a large-scale mark–recapture program where ∼8000 rainbow trout were recaptured over a 3-year period (2012–2014). There were strong temporal and spatial variations in growth in both length and weight as predicted from von Bertalanffy and bioenergetic models, respectively. There was more evidence for seasonal variation in the growth coefficient and annual variation in the asymptotic length. Bioenergetic models showed more variability for growth in weight across seasons and years than across reaches. These patterns were consistent with strong seasonal variation in invertebrate drift and effects of turbidity on foraging efficiency. Highest growth rates and relative condition occurred in downstream reaches with lower trout densities. Results indicate that reduction in rainbow trout abundance in Glen Canyon will likely increase trout size in the tailwater fishery and may reduce downstream dispersal into Grand Canyon.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2015-0102
Volume 73
Issue 1
Year Published 2016
Language English
Publisher NRC Research Press
Contributing office(s) Southwest Biological Science Center
Description 15 p.
First page 125
Last page 139
Country United States
State Arizona
Other Geospatial Colorado River, Grand Canyon
Online Only (Y/N) N
Additional Online Files (Y/N) N