DOI: 10.5061/dryad.3j9kd51x3
title: Sex-dependent shifts in visual detection thresholds under turbid conditions in an African cichlid

description: Turbidity is increasing in freshwaters globally due to human activities
 and is known to affect visually-mediated behaviors in fish. As
 anthropogenic impacts continue to degrade aquatic environments, it is
 critical to determine how sensory systems are affected and what this might
 mean for population persistence. We investigated the effect of turbidity
 on visual detection thresholds in an African cichlid fish
 (Pseudocrenilabrus multicolor) that experiences environmental extremes
 across its East African range. We tested the visual abilities of adult
 wild-caught fish from two sites representing the extremes of turbidity and
 oxygen (a high turbidity, high dissolved oxygen river and a low turbidity,
 low dissolved oxygen swamp). Further, we reared offspring of wild-caught
 parents from each population in a full-factorial high/low oxygen, high/low
 turbidity design to tease apart the influence of each stressor on visual
 detection thresholds. We used an optomotor response test to determine
 detection thresholds under increasing levels of turbidity for both
 wild-caught and lab-reared fish. Detection thresholds were higher in the
 wild-caught river population compared to the swamp population, and there
 was a strong sex difference, such that wild-caught males had higher
 detection thresholds than females, regardless of population of origin. Our
 results suggest that there are sex-based differences in contrast detection
 abilities that could play a critical role in visual ecology for
 populations experiencing divergent turbidity regimes. In the rearing
 experiment, sex-based differences in detection thresholds were influenced
 by different aspects of the rearing treatment. Detection threshold varied
 significantly by oxygen rearing treatment for males and by the interactive
 effects of oxygen and turbidity for females. This research improves our
 understanding of the effect of elevated turbidity on African cichlid
 vision and contributes to growing knowledge of how animals respond to
 environmental change. Ethics statement:  All research was
 approved by The Ohio State University Institutional Animal Care and Use
 Committee (2014A00000055-R1). Permission was given by the Commissioner of
 Fisheries Resources Management and Development, Uganda, for export of
 fish, and from the Uganda National Council for Science and Technology for
 permission to conduct research.
description: # Sex-dependent shifts in visual detection thresholds under turbid
 conditions in an African cichlid This file contains metadata for two files
 used in two R scripts associated with this manuscript. Description for
 WILD CAUGHT: field_opto.xlsx used in field-opto_analysis.R All code is
 provided for the analyses as described in the manuscript.
 Pseudocrenilabrus multicolor (haplochromine cichlid fish) were collected
 from two sites in western Uganda and used as the parental population for a
 rearing experiment. Each row in the dataset represents metrics for a
 single fish. Variable Description ID:   individual number assigned to each
 fish Population:  coded for variable for each Population (NYA=River,
 LWA=Swamp) Sex: sex of individual fish SL: standard length of fish (cm) T1
 - direction: randomly determined direction of optomotor apparatus
 (clockwise (C) or counterclockwise (CC)) for trial 1 T1 - stop: detection
 threshold; ending turbidity for trial 1 in NTU T2 - direction: randomly
 determined direction of optomotor apparatus (clockwise (C) or
 counterclockwise (CC)) for trial 2 T2 - stop: detection threshold; ending
 turbidity for trial 2 in NTU ave: average of T1 - stop and T2 - stop diff:
 the difference between T1 - stop and T2 - stop Description for REARING:
 rearing_opto.xlsx used in rearing-opto_analysis.R All code is provided for
 the analyses as described in the manuscript. Pseudocrenilabrus multicolor
 (haplochromine cichlid fish) were collected from two sites in western
 Uganda and used as the parental population for a rearing experiment. Each
 row in the dataset represents metrics for a single fish. Variable
 Description ID: individual number assigned to each fish Population: coded
 for variable for each Population (NYA=River, LWA=Swamp) Rearing: coded for
 variable for rearing treatment (hypoxic-clear (HC); hypoxic-turbid (HT);
 normoxic-clear (HC); normoxic-turbid (HT)). Oxygen: coded for variable for
 rearing treatment (hypoxic (H); normoxic (N)) Turbidity: coded for
 variable for rearing treatment (clear (C); turbid (T)) Tank: rearing tank
 number Brood: brood identifier Sex: sex of individual fish SL: standard
 length of fish (cm) T1 - direction: randomly determined direction of
 optomotor apparatus (clockwise (C) or counterclockwise (CC)) for trial 1
 T1 - stop: detection threshold; ending turbidity for trial 1 in NTU T2 -
 direction: randomly determined direction of optomotor apparatus (clockwise
 (C) or counterclockwise (CC)) for trial 2 T2 - stop: detection threshold;
 ending turbidity for trial 2 in NTU ave: average of T1 - stop and T2 -
 stop diff: the difference between T1 - stop and T2 - stop