Data from: Enhanced conspicuousness of prey in warmer water mitigates the constraint of turbidity for predators
Data files
Jul 17, 2025 version files 38.25 KB
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Final_data.csv
36.26 KB
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README.md
1.99 KB
Abstract
Changes in environmental conditions impact predator-prey interactions by altering behaviour through sensory and non-sensory (e.g., metabolic or cognitive) pathways. Elevated water temperature and turbidity are known to alter activity levels and anti-predator responses in prey fish, and are increasing globally as a result of anthropogenic activities. Less is known about how temperature and turbidity impact predators’ ability to detect prey directly, or indirectly via changes to prey behaviour. We quantified the detectability of Trinidadian guppies (Poecilia reticulata) free-swimming in a large arena from the perspective of a stationary visual predator (simulated as an underwater camera). We used a fully factorial experimental design testing the independent and combined effects of increased temperature and turbidity. We found that both stressors had a strong influence on the appearance of prey (objectively quantified as the mean magnitude of the optical flow in the videos). As expected, turbidity reduced the frequency of detection between the guppies and the simulated predator, i.e., the magnitude of optical flow exceeded the threshold for a ‘detection event’ more often in clear water. Events were also shorter in duration in turbid water, reducing the time available for a predator to detect the prey. However, during an event, prey were more detectable in warmer water (i.e., the mean magnitude was greater). Although we found no evidence of interactive effects of turbidity and temperature on the response variables, their cumulative main effects suggest an antagonistic effect between the two stressors on the predator-prey dynamic overall.
Data files included:
1. Final_data.csv
This data file includes all averaged variables used in the statistical analysis described in the Methods section
- VideoFile: Unique trial identifier. Video files are not included in this repository. Available on request by contacting the first author CZ directly on cos.zanghi@bristol.ac.uk or cos.zan@gmail.com.
- MeanMagnitude MaxMagnitude: mean and max average magnitude of optical flow for each trial
- Trail_N: Unique Trial Number 1-96
- Guppy_tub: Number of holding tanks of origin 1-4
- Guppy_group : number of group tested each day 1-6
- Guppy_N : number of individual guppies within each group
- Rep_Testing : Repeated testing 1-4
- Min_from_Midnight: minutes passed from midnight when trial commenced
- SqrMean SqrMax : Square root transformations of mean and max magnitude
- Treatment : categorical variable
- Temp : categorical variable, H = Hot, W = Warm
- Turb : categorical variable, C = Clear, T = Turbid
- Proportion_Yes99 Proportion_Yes95 Proportion_Yes90 Proportion_Yes80 Proportion_Yes70 : Proportion of detection events for each of the 5 thresholds
- Mean_Magnitude_Yes99 Mean_Magnitude_Yes95 Mean_Magnitude_Yes90 Mean_Magnitude_Yes80 Mean_Magnitude_Yes70 : Mean Magnitude for each of the 5 thresholds
- Mean_Event_Duration99 Mean_Event_Duration95 Mean_Event_Duration90 Mean_Event_Duration80 Mean_Event_Duration70 : Mean duration of events for each of the 5 thresholds
- encounters99 encounters95 encounters90 encounters80 encounters70 : Number of events for each of the 5 thresholds
Scripts included:
1. CH_3_stats_v.4.R
This script describes the final steps of data manipulation: where values of mean magnitude were used to calculated further metrics (i.e. Proportion of events, Number of events and Duration of events). Preliminary data for these steps are available on request. Then, under the ### STATS ### heading, the analysis to support the finding reported in the paper is reported.