Biology subjects

Peterka, J.

Publications and source records attributed to Peterka, J..

3 recordsLinked to original sources

bioRxiv2024

Hungry catfish - effect of prey availability on movement dynamics of a top predator

O_LIThe availability and spatial distribution of prey determines the energetic costs of predators foraging and largely drives their space use, activity level and foraging timing. Consequently, predators in ecosystems with different prey availability and distribution should adjust their movement patterns to optimise their foraging success in order to maximise efficiency. C_LIO_LIThe aim of this study was to investigate the ability of a top predator, European catfish (Silurus glanis), to adapt its space use, temporal activity and diet patterns in environments with varying prey density and distribution, and to examine the consequences for the catfishs body growth. C_LIO_LICatfish activity, tracked with high-resolution acoustic telemetry positioning systems deployed in two oligotrophic lakes with limited fish prey and one eutrophic reservoir with abundant fish prey, showed clear differences in their spatial and foraging behaviour. In oligotrophic, prey-poor lakes, catfish showed larger space use, altered diurnal activity patterns, reduced use of the open water, increased variability in inter- and intra-individual space use and had a more diverse diet compared to their conspecifics in the eutrophic, prey-rich reservoir. However, despite these behavioural alterations the reduced food availability in prey-poor lakes ultimately led to a reduced catfish growth, as these behavioural changes could not fully compensate for the lower prey fish abundance. C_LIO_LIThe study showed that top predators can combine different behavioural mechanisms and individual strategies to adapt to different ecological contexts. The observed ability of catfish to optimize activity, space use and diet highlights the evolutionary need to maximise foraging efficiency and overall fitness in different habitats, giving catfish a significant competitive advantage. Such competitive abilities are prerequisites for the actual catfish success as an invasive species within a Europe. C_LI

ecology↗

bioRxiv2021

Dynamics of the habitat use of three predatory freshwater fish in a lentic ecosystem

To understand the conditions of coexistence in multiple-species predator community, we studied longitudinal and vertical movement of pike (Esox lucius), pikeperch (Sander lucioperca) and catfish (Silurus glanis) in the [R]imov Reservoir, using an autonomous telemetry system for 11 months. We found significant differences among these three species in movement and depth that varied considerably in time, with the greatest differences between warm (late spring and early autumn) and cold season (late autumn to early spring). Preference for different sections of the reservoir was stable for pike, while pikeperch and catfish frequently visited tributary during the warm season, and moved closer to the dam during the cold season. Pike longitudinal activity was highest in the cold season, pikeperch in the warm season, and catfish activity peaked in both the warm and cold seasons. Overlap in the depth used among species was higher in the warm season, when all species used the upper layer of the water column, and lower in cold season, when pikeperch and catfish used deeper areas. These results demonstrated ability of predators to actively inspect a large portion of the reservoir in both longitudinal and vertical dimensions, although differing in the timing of their habitat use and activity.

ecology↗

bioRxiv2021

Influence of internal seiche dynamics on vertical movement of fish

O_LIInternal seiches are common in stratified lakes, with significant effects on stratification patterns, hydrodynamics and vertical nutrient transport. In particular, seiche can change the vertical distribution of the thermocline and the cold hypolimnetic and warm epilimnetic water masses by several meters on a timescale of a few hours. The results are rapid and strong changes in temperature profiles and oxygen availability that can have profound effects on vagrant and sessile organisms. Internal seiche dynamics could therefore affect fish communities directly through physiological stress and elevated mortality, and indirectly through prey distribution. C_LIO_LIThe aim of this study was to analyze the effects of internal seiche dynamics on lacustrine fish behaviour, and to characterize fish reaction patterns, with the main focus on vertical movement of fish in the vicinity of a shifting thermocline, and avoidance of cold hypolimnetic water. C_LIO_LIThe analysis was based on acoustic telemetry data from Lake Milada, a post-mining lake in the Czech Republic, with a total of 55 tracked individuals of four species: northern pike (Esox lucius), wels catfish (Silurus glanis), tench (Tinca tinca) and rudd (Scardinius erythropthalmus). C_LIO_LIThe effects of seiche dynamics on the four species studied were weak but significant during the day, but only on rudd during the night. Upward seiche produced stronger reactions in fish than downward seiche, and the effects were manifested only during the strongest seiche events. C_LIO_LIThermocline shifting during seiche events may induce a transient reduction in habitat for seiche-reacting species, thus potentially affecting predation and other inter- and intra-specific interactions, and probably affecting fish community dynamics. C_LI Graphical abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

ecology↗