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Body size and condition influence migration timing of juvenile Arctic grayling

Ecology of Freshwater Fish

By:
, ORCID iD , , and
https://doi.org/10.1111/eff.12199

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Abstract

Freshwater fishes utilising seasonally available habitats within annual migratory circuits time movements out of such habitats with changing hydrology, although individual attributes of fish may also mediate the behavioural response to environmental conditions. We tagged juvenile Arctic grayling in a seasonally flowing stream on the Arctic Coastal Plain in Alaska and recorded migration timing towards overwintering habitat. We examined the relationship between individual migration date, and fork length (FL) and body condition index (BCI) for fish tagged in June, July and August in three separate models. Larger fish migrated earlier; however, only the August model suggested a significant relationship with BCI. In this model, 42% of variability in migration timing was explained by FL and BCI, and fish in better condition were predicted to migrate earlier than those in poor condition. Here, the majority (33%) of variability was captured by FL with an additional 9% attributable to BCI. We also noted strong seasonal trends in BCI reflecting overwinter mass loss and subsequent growth within the study area. These results are interpreted in the context of size and energetic state-specific risks of overwinter starvation and mortality (which can be very high in the Arctic), which may influence individuals at greater risk to extend summer foraging in a risky, yet prey rich, habitat. Our research provides further evidence that heterogeneity among individuals within a population can influence migratory behaviour and identifies potential risks to late season migrants in Arctic beaded stream habitats influenced by climate change and petroleum development.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Body size and condition influence migration timing of juvenile Arctic grayling
Series title:
Ecology of Freshwater Fish
DOI:
10.1111/eff.12199
Volume:
25
Issue:
1
Year Published:
2016
Language:
English
Publisher:
John Wiley & Sons
Contributing office(s):
Coop Res Unit Seattle
Description:
11 p.
First page:
156
Last page:
166
Country:
United States
State:
Alaska
Other Geospatial:
Ublutuoch River
Online Only (Y/N):
N
Additional Online Files (Y/N):
N