Abstract
Salmonids form dominance hierarchies in environments, where space or food are limiting. Our first objective was to investigate the physiology of individual rainbow trout in 4-fish hierarchies. Our second was to compare conclusions drawn from grouping physiological data on the basis of social rank with those based on relating individual physiology to individual aggressive behavior. To create a social hierarchy, groups of 4 juvenile trout were fed (1 % ration) using a darkened feeding container, twice daily (morning and evening). Each morning feeding was videotaped to record aggressive behavior, thereby facilitating the assignment of a social status rank to each fish. On days 5 and 10-11, physiological parameters were measured in fish fasted for 24 h. Social hierarchies formed in all tested groups. One fish would become dominant, whereas the three subordinate individuals would each assume a stable social rank. When classified according to this social rank, the three subordinate individuals all displayed similar physiology, different from the physiology of the dominant fish. The latter included higher ammonia excretion rate, greater protein utilization in aerobic metabolism, greater feeding, higher specific growth rate, greater increase in condition factor, and lower routine oxygen consumption rate. However, when individual aggression was taken into account, a continuous gradient was observed between aggression and physiology for most parameters, regardless of social status. These relationships could be improved by normalizing the aggression score to the overall level of aggression in each hierarchy. We argue that individual behavior should be considered instead of just social rank when studying the physiology of trout in social hierarchies.
| Original language | English |
|---|---|
| Pages (from-to) | 787-799 |
| Number of pages | 13 |
| Journal | Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology |
| Volume | 183 |
| Issue number | 6 |
| DOIs | |
| State | Published - Aug 1 2013 |
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Keywords
- Aggression
- Ammonia excretion
- Feeding
- Growth
- Oxygen consumption
- Social rank
ASJC Scopus subject areas
- Physiology
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology
- Biochemistry
- Endocrinology
Cite this
The physiology of rainbow trout in social hierarchies : Two ways of looking at the same data. / Grobler, Josias M B; Wood, Chris M.
In: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology, Vol. 183, No. 6, 01.08.2013, p. 787-799.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The physiology of rainbow trout in social hierarchies
T2 - Two ways of looking at the same data
AU - Grobler, Josias M B
AU - Wood, Chris M.
PY - 2013/8/1
Y1 - 2013/8/1
N2 - Salmonids form dominance hierarchies in environments, where space or food are limiting. Our first objective was to investigate the physiology of individual rainbow trout in 4-fish hierarchies. Our second was to compare conclusions drawn from grouping physiological data on the basis of social rank with those based on relating individual physiology to individual aggressive behavior. To create a social hierarchy, groups of 4 juvenile trout were fed (1 % ration) using a darkened feeding container, twice daily (morning and evening). Each morning feeding was videotaped to record aggressive behavior, thereby facilitating the assignment of a social status rank to each fish. On days 5 and 10-11, physiological parameters were measured in fish fasted for 24 h. Social hierarchies formed in all tested groups. One fish would become dominant, whereas the three subordinate individuals would each assume a stable social rank. When classified according to this social rank, the three subordinate individuals all displayed similar physiology, different from the physiology of the dominant fish. The latter included higher ammonia excretion rate, greater protein utilization in aerobic metabolism, greater feeding, higher specific growth rate, greater increase in condition factor, and lower routine oxygen consumption rate. However, when individual aggression was taken into account, a continuous gradient was observed between aggression and physiology for most parameters, regardless of social status. These relationships could be improved by normalizing the aggression score to the overall level of aggression in each hierarchy. We argue that individual behavior should be considered instead of just social rank when studying the physiology of trout in social hierarchies.
AB - Salmonids form dominance hierarchies in environments, where space or food are limiting. Our first objective was to investigate the physiology of individual rainbow trout in 4-fish hierarchies. Our second was to compare conclusions drawn from grouping physiological data on the basis of social rank with those based on relating individual physiology to individual aggressive behavior. To create a social hierarchy, groups of 4 juvenile trout were fed (1 % ration) using a darkened feeding container, twice daily (morning and evening). Each morning feeding was videotaped to record aggressive behavior, thereby facilitating the assignment of a social status rank to each fish. On days 5 and 10-11, physiological parameters were measured in fish fasted for 24 h. Social hierarchies formed in all tested groups. One fish would become dominant, whereas the three subordinate individuals would each assume a stable social rank. When classified according to this social rank, the three subordinate individuals all displayed similar physiology, different from the physiology of the dominant fish. The latter included higher ammonia excretion rate, greater protein utilization in aerobic metabolism, greater feeding, higher specific growth rate, greater increase in condition factor, and lower routine oxygen consumption rate. However, when individual aggression was taken into account, a continuous gradient was observed between aggression and physiology for most parameters, regardless of social status. These relationships could be improved by normalizing the aggression score to the overall level of aggression in each hierarchy. We argue that individual behavior should be considered instead of just social rank when studying the physiology of trout in social hierarchies.
KW - Aggression
KW - Ammonia excretion
KW - Feeding
KW - Growth
KW - Oxygen consumption
KW - Social rank
UR - http://www.scopus.com/inward/record.url?scp=84880597896&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84880597896&partnerID=8YFLogxK
U2 - 10.1007/s00360-013-0752-5
DO - 10.1007/s00360-013-0752-5
M3 - Article
C2 - 23543045
AN - SCOPUS:84880597896
VL - 183
SP - 787
EP - 799
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
SN - 0174-1578
IS - 6
ER -