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Influence of fear on the behavioural decisions of common roach (rutilus rutilus)

Pirroni, Sara (2018) BION03 20172
Degree Projects in Biology
Abstract
Under predation risk, a trade-off between the need for safety and foraging opportunity occurs. Fish have been shown to adopt several behavioural strategies in order to reduce the risk of being attacked by a predator. In order to deeper investigate this phenomenon, in the present study common roach (Rutilus rutilus) behavioural personalities have been assessed under laboratory conditions and in the wild in the presence/absence of northern pike (Esox lucius). According to the hypothesis suggested, roach showed a behavioural change in personality between the lab and the natural environment. However, differently to what was expected, in presence of a higher predation risk in the wild, roach showed a decrease in social behaviour and activity... (More)
Under predation risk, a trade-off between the need for safety and foraging opportunity occurs. Fish have been shown to adopt several behavioural strategies in order to reduce the risk of being attacked by a predator. In order to deeper investigate this phenomenon, in the present study common roach (Rutilus rutilus) behavioural personalities have been assessed under laboratory conditions and in the wild in the presence/absence of northern pike (Esox lucius). According to the hypothesis suggested, roach showed a behavioural change in personality between the lab and the natural environment. However, differently to what was expected, in presence of a higher predation risk in the wild, roach showed a decrease in social behaviour and activity while increasing boldness. This indicates that common roach responded to altered risk by changing behavioural strategy and adopting new features in order to increase the vigilance and consequently reduce the risk of falling victim to predators. Furthermore, when in presence of pike, roach showed a non-significant decrease in activity with peaks in activity during daylight hours as a result of their foraging strategy and environmental conditions. Despite these results show that fish respond to fear with many behavioural strategies, there is still the need of future research in order to have a deeper knowledge of roach personality and to understand to what extent the presence of a predator can influence fish personality and consequently predator-prey interactions. (Less)
Popular Abstract
Effects of fear on common roach (Rutilus rutilus)

The presence of a predator can affect fish behavioral traits in multiple ways and determine a trade-off between the need for safety and foraging opportunity. In order to reduce the risk of being attacked by predators, fish have been shown to adopt different behavioral strategies.

To deeper investigate this phenomenon, the behavioural responses (activity, sociability and boldness) of common roach (Rutilus rutilus) to predation risk were first conducted in the lab in the absence of predators and later compared to fish spatial behaviour assessed in an artificial pond in the presence/absence of northern pike (Esox Lucius). In the lab, boldness was assessed considering the time for fish... (More)
Effects of fear on common roach (Rutilus rutilus)

The presence of a predator can affect fish behavioral traits in multiple ways and determine a trade-off between the need for safety and foraging opportunity. In order to reduce the risk of being attacked by predators, fish have been shown to adopt different behavioral strategies.

To deeper investigate this phenomenon, the behavioural responses (activity, sociability and boldness) of common roach (Rutilus rutilus) to predation risk were first conducted in the lab in the absence of predators and later compared to fish spatial behaviour assessed in an artificial pond in the presence/absence of northern pike (Esox Lucius). In the lab, boldness was assessed considering the time for fish to emerge completely from a refuge box, sociability as the time spent close to a group of conspecifics, and activity as cumulative time moving. In the field, fish personality was evaluated using acoustic transmitters/receivers, considering three different periods: only roach, roach in presence of caged pike, and roach with pike released. The sociability of each roach individual was quantified as the distance from its conspecifics, boldness as the distance between individual roach and predators ( pike) and activity as distance moved. Furthermore, the diel variation of activity was also evaluated.

In accordance with the hypothesis, roach showed a change in personality between laboratory conditions and the natural habitat. However, this hypothesis was partly rejected by the significant positive correlation for activity in the natural environment and in laboratory conditions, indicating the outcome of the smaller-scale laboratory experiments representing the natural personality of roach. In contrast to what it was expected, under higher predation risk, roach showed a decrease in sociability and activity while increasing boldness (Fig.1). In addition, peaks in activity were recorded during daylight hours.


The outcomes of this study indicate that common roach can respond to predation risk adopting uncommon behavioural strategies such as predator inspection in order to increase the vigilance and reduce the likelihood of falling victim to predators. The higher activity during daytime is attributable to the foraging strategy of this freshwater fish that relies on sight during daytime. Despite these findings, there is still the need for further investigations in order to have a deeper knowledge of roach personality and to understand to what extent the presence of a predator can influence personality. Moreover, future studies including environmental factors such as light and temperature in assays of sociability and boldness would be interesting. The present study represents only in a small scale how predation risk can affect fish behavioural traits, there is therefore the need of future research in order to get the whole picture of roach behavioural responses to predation risk and to understand how population dynamics and predator-prey interactions are consequently impacted.

Master’s Degree Project in Biology 60 credits 2018
Department of Biology, Lund University

Advisors: Anders Nilsson and Christer Brönmark
Department of Biology-Aquatic Ecology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Pirroni, Sara
supervisor
organization
course
BION03 20172
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8958549
date added to LUP
2018-09-12 14:54:44
date last changed
2018-09-12 14:54:44
@misc{8958549,
  abstract     = {Under predation risk, a trade-off between the need for safety and foraging opportunity occurs. Fish have been shown to adopt several behavioural strategies in order to reduce the risk of being attacked by a predator. In order to deeper investigate this phenomenon, in the present study common roach (Rutilus rutilus) behavioural personalities have been assessed under laboratory conditions and in the wild in the presence/absence of northern pike (Esox lucius). According to the hypothesis suggested, roach showed a behavioural change in personality between the lab and the natural environment. However, differently to what was expected, in presence of a higher predation risk in the wild, roach showed a decrease in social behaviour and activity while increasing boldness. This indicates that common roach responded to altered risk by changing behavioural strategy and adopting new features in order to increase the vigilance and consequently reduce the risk of falling victim to predators. Furthermore, when in presence of pike, roach showed a non-significant decrease in activity with peaks in activity during daylight hours as a result of their foraging strategy and environmental conditions. Despite these results show that fish respond to fear with many behavioural strategies, there is still the need of future research in order to have a deeper knowledge of roach personality and to understand to what extent the presence of a predator can influence fish personality and consequently predator-prey interactions.},
  author       = {Pirroni, Sara},
  language     = {eng},
  note         = {Student Paper},
  title        = {Influence of fear on the behavioural decisions of common roach (rutilus rutilus)},
  year         = {2018},
}