Variation in movement between individuals can have important ecological effects on populations an... more Variation in movement between individuals can have important ecological effects on populations and ecosystems, yet the factors driving differences in movement and their consequences remain poorly understood. Here, individual variability in the movements of juvenile (age 0 + and 1 + year) pike Esox lucius was assessed using passive integrated transponder (PIT) telemetry in off-channel nursery areas over a 26-month period. Differences in the movement patterns of individuals were tested against their body sizes, ages, growth rates and trophic positions using data collected through a combination of catch-and-release sampling and stable isotope analyses. Results revealed that variation in movement between individuals was affected by age, with 1 + individuals moving more than individuals of age 0 + , but not length. Individuals whose TP was low on their initial capture event moved significantly less than those with a higher initial TP. Individuals that moved more grew faster and achieved a higher final TP. These results suggest that higher activity (i.e., increased movement) increases resource acquisition that enhances growth rates, which could ultimately maximise individual performances. K E Y W O R D S Inter-individual variation, movement, PIT telemetry, stable isotope analyses
The correlation of seemingly unrelated behaviours into behavioural syndromes has been established... more The correlation of seemingly unrelated behaviours into behavioural syndromes has been established in a wide range of species and taxa. However, most studies report on short-term behavioural correlations without insight into individual consistency or temporal stability of the behavioural syndrome. Here, we examine the individual repeatability of single behaviours, and the presence and temporal stability of a context-general behavioural syndrome in a solitary piscivorous predator, the pike (Esox lucius). Behavioural measurements on the same individuals were quantified independently through time and across three contexts: activity in the presence of a competitor, exploration of a novel environment and boldness under predation risk. There was no indication of a temporally stable behavioural syndrome, consisting of boldness, activity and exploration, nor were individuals consistent in the separate behaviours, contradicting the general assertion of its taxonomic prevalence. Furthermore, the study did not provide support for size or growth-dependent behaviour in this size-dimorphic species in conditions of limited food availability. The study highlights the importance of independent multiple observations of individual behaviour across time or contexts when measuring behavioural repeatability and covariation.
Models explaining behavioural syndromes often focus on state-dependency, linking behavioural vari... more Models explaining behavioural syndromes often focus on state-dependency, linking behavioural variation to individual differences in other phenotypic features. Empirical studies are, however, rare. Here, we tested for a size and growthdependent stable behavioural syndrome in the juvenile-stages of a solitary apex predator (pike, Esox lucius), shown as repeatable foraging behaviour across risk. Pike swimming activity, latency to prey attack, number of successful and unsuccessful prey attacks was measured during the presence/absence of visual contact with a competitor or predator. Foraging behaviour across risks was considered an appropriate indicator of boldness in this solitary predator where a tradeoff between foraging behaviour and threat avoidance has been reported. Support was found for a behavioural syndrome, where the rank order differences in the foraging behaviour between individuals were maintained across time and risk situation. However, individual behaviour was independent of body size and growth in conditions of high food availability, showing no evidence to support the state-dependent personality hypothesis. The importance of a combination of spatial and temporal environmental variation for generating growth differences is highlighted.
In coastal waters filamentous algal growths have increased due to eutrophication. At some stage, ... more In coastal waters filamentous algal growths have increased due to eutrophication. At some stage, algal filaments come loose and start drifting in the water column where they become important transient resources for ambient invertebrates, before they gather at the bottom and start decaying. By field experiments, we have quantitatively studied how macrofauna temporarily utilise these filamentous algae, and whether large water depths or long distances from the shore restrict or promote the colonisation process. Further we have compared macrofauna colonisation rates to algae in the water column and to algae lying at the sediment.
Variation in movement between individuals can have important ecological effects on populations an... more Variation in movement between individuals can have important ecological effects on populations and ecosystems, yet the factors driving differences in movement and their consequences remain poorly understood. Here, individual variability in the movements of juvenile (age 0 + and 1 + year) pike Esox lucius was assessed using passive integrated transponder (PIT) telemetry in off-channel nursery areas over a 26-month period. Differences in the movement patterns of individuals were tested against their body sizes, ages, growth rates and trophic positions using data collected through a combination of catch-and-release sampling and stable isotope analyses. Results revealed that variation in movement between individuals was affected by age, with 1 + individuals moving more than individuals of age 0 + , but not length. Individuals whose TP was low on their initial capture event moved significantly less than those with a higher initial TP. Individuals that moved more grew faster and achieved a higher final TP. These results suggest that higher activity (i.e., increased movement) increases resource acquisition that enhances growth rates, which could ultimately maximise individual performances. K E Y W O R D S Inter-individual variation, movement, PIT telemetry, stable isotope analyses
The correlation of seemingly unrelated behaviours into behavioural syndromes has been established... more The correlation of seemingly unrelated behaviours into behavioural syndromes has been established in a wide range of species and taxa. However, most studies report on short-term behavioural correlations without insight into individual consistency or temporal stability of the behavioural syndrome. Here, we examine the individual repeatability of single behaviours, and the presence and temporal stability of a context-general behavioural syndrome in a solitary piscivorous predator, the pike (Esox lucius). Behavioural measurements on the same individuals were quantified independently through time and across three contexts: activity in the presence of a competitor, exploration of a novel environment and boldness under predation risk. There was no indication of a temporally stable behavioural syndrome, consisting of boldness, activity and exploration, nor were individuals consistent in the separate behaviours, contradicting the general assertion of its taxonomic prevalence. Furthermore, the study did not provide support for size or growth-dependent behaviour in this size-dimorphic species in conditions of limited food availability. The study highlights the importance of independent multiple observations of individual behaviour across time or contexts when measuring behavioural repeatability and covariation.
Models explaining behavioural syndromes often focus on state-dependency, linking behavioural vari... more Models explaining behavioural syndromes often focus on state-dependency, linking behavioural variation to individual differences in other phenotypic features. Empirical studies are, however, rare. Here, we tested for a size and growthdependent stable behavioural syndrome in the juvenile-stages of a solitary apex predator (pike, Esox lucius), shown as repeatable foraging behaviour across risk. Pike swimming activity, latency to prey attack, number of successful and unsuccessful prey attacks was measured during the presence/absence of visual contact with a competitor or predator. Foraging behaviour across risks was considered an appropriate indicator of boldness in this solitary predator where a tradeoff between foraging behaviour and threat avoidance has been reported. Support was found for a behavioural syndrome, where the rank order differences in the foraging behaviour between individuals were maintained across time and risk situation. However, individual behaviour was independent of body size and growth in conditions of high food availability, showing no evidence to support the state-dependent personality hypothesis. The importance of a combination of spatial and temporal environmental variation for generating growth differences is highlighted.
In coastal waters filamentous algal growths have increased due to eutrophication. At some stage, ... more In coastal waters filamentous algal growths have increased due to eutrophication. At some stage, algal filaments come loose and start drifting in the water column where they become important transient resources for ambient invertebrates, before they gather at the bottom and start decaying. By field experiments, we have quantitatively studied how macrofauna temporarily utilise these filamentous algae, and whether large water depths or long distances from the shore restrict or promote the colonisation process. Further we have compared macrofauna colonisation rates to algae in the water column and to algae lying at the sediment.
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Papers by Marina Nyqvist