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Ice cover alters the behavior and stress level of brown trout Salmo trutta

Watz, Johan; Bergman, Eva; Calles, Olle; Enefalk, Asa; Gustafsson, Stina; Hagelin, Anna; Nilsson, Anders LU ; Norrgard, Johnny R.; Nyqvist, Daniel and Osterling, E. Martin, et al. (2015) In Behavioral Ecology 26(3). p.820-827
Abstract
Surface ice in rivers and lakes buffers the thermal environment and provides overhead cover, protecting aquatic animals from terrestrial predators. We tested if surface ice influenced the behavior (swimming activity, aggressive encounters, and number of food items eaten) and stress level (coloration of eyes and body) of stream-living brown trout Salmo trutta at temperatures of 3-4 degrees C in indoor experimental flumes. We hypothesized that an individual's resting metabolic rate (RMR, as measured by resting ventilation rate) would affect winter behavior. Therefore, groups of 4 trout, consisting of individuals with high, low, or mixed (2 individuals each) RMR, were exposed to experimental conditions with or without ice cover. Ice cover... (More)
Surface ice in rivers and lakes buffers the thermal environment and provides overhead cover, protecting aquatic animals from terrestrial predators. We tested if surface ice influenced the behavior (swimming activity, aggressive encounters, and number of food items eaten) and stress level (coloration of eyes and body) of stream-living brown trout Salmo trutta at temperatures of 3-4 degrees C in indoor experimental flumes. We hypothesized that an individual's resting metabolic rate (RMR, as measured by resting ventilation rate) would affect winter behavior. Therefore, groups of 4 trout, consisting of individuals with high, low, or mixed (2 individuals each) RMR, were exposed to experimental conditions with or without ice cover. Ice cover reduced stress responses, as evaluated by body coloration. Also, trout in low RMR groups had a paler body color than those in both mixed and high RMR groups. Trout increased their swimming activity under ice cover, with the highest activity found in high RMR groups. Ice cover increased the number of aggressive encounters but did not influence the number of drifting food items taken by each group. In mixed RMR groups, however, single individuals were better able to monopolize food than in the other groups. As the presence of surface ice increases the activity level and reduces stress in stream-living trout, ice cover should influence their energy budgets and production. The results should be viewed in light of ongoing global warming that reduces the duration of ice cover, especially at high latitudes and altitudes. (Less)
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Contribution to journal
publication status
published
subject
keywords
aggression, climate change, energy budget, metabolic rate, winter
in
Behavioral Ecology
volume
26
issue
3
pages
820 - 827
publisher
Oxford University Press
external identifiers
  • wos:000356585100024
  • scopus:84941635238
ISSN
1045-2249
DOI
10.1093/beheco/arv019
language
English
LU publication?
yes
id
d0688b95-d5a9-4522-b69b-802498378d04 (old id 7791096)
date added to LUP
2015-09-09 14:54:25
date last changed
2017-10-01 04:24:57
@article{d0688b95-d5a9-4522-b69b-802498378d04,
  abstract     = {Surface ice in rivers and lakes buffers the thermal environment and provides overhead cover, protecting aquatic animals from terrestrial predators. We tested if surface ice influenced the behavior (swimming activity, aggressive encounters, and number of food items eaten) and stress level (coloration of eyes and body) of stream-living brown trout Salmo trutta at temperatures of 3-4 degrees C in indoor experimental flumes. We hypothesized that an individual's resting metabolic rate (RMR, as measured by resting ventilation rate) would affect winter behavior. Therefore, groups of 4 trout, consisting of individuals with high, low, or mixed (2 individuals each) RMR, were exposed to experimental conditions with or without ice cover. Ice cover reduced stress responses, as evaluated by body coloration. Also, trout in low RMR groups had a paler body color than those in both mixed and high RMR groups. Trout increased their swimming activity under ice cover, with the highest activity found in high RMR groups. Ice cover increased the number of aggressive encounters but did not influence the number of drifting food items taken by each group. In mixed RMR groups, however, single individuals were better able to monopolize food than in the other groups. As the presence of surface ice increases the activity level and reduces stress in stream-living trout, ice cover should influence their energy budgets and production. The results should be viewed in light of ongoing global warming that reduces the duration of ice cover, especially at high latitudes and altitudes.},
  author       = {Watz, Johan and Bergman, Eva and Calles, Olle and Enefalk, Asa and Gustafsson, Stina and Hagelin, Anna and Nilsson, Anders and Norrgard, Johnny R. and Nyqvist, Daniel and Osterling, E. Martin and Piccolo, John J. and Schneider, Lea D. and Greenberg, Larry and Jonsson, Bror},
  issn         = {1045-2249},
  keyword      = {aggression,climate change,energy budget,metabolic rate,winter},
  language     = {eng},
  number       = {3},
  pages        = {820--827},
  publisher    = {Oxford University Press},
  series       = {Behavioral Ecology},
  title        = {Ice cover alters the behavior and stress level of brown trout Salmo trutta},
  url          = {http://dx.doi.org/10.1093/beheco/arv019},
  volume       = {26},
  year         = {2015},
}