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. 2026 Jul 3;109(3):1786–1799. doi: 10.1111/jfb.70556

Impacts of predator odours and conspecific disturbance cues on minnow thermal tolerance

V Groves 1,✉, M Morissette 1, L Nagpal 1, N E Mandrak 2, L J Chapman 1
PMCID: PMC13602091  PMID: 42397083

Abstract

Warming waters can affect fish community dynamics, potentially exacerbating predator–prey asymmetries in behavioural and physiological metrics of thermal tolerance. Further, differing responses of prey fish species to concurrent predation risk and warming highlight the need to understand these impacts in various contexts, especially with at‐risk species. This study explored variation in thermal tolerance between the Threatened pugnose shiner (Miniellus anogenus) and non‐threatened congener blackchin shiner (Miniellus heterodon) given concurrent exposure to warming and predation risk via chemical cues. Using a series of three channel‐side experiments, we (1) explored whether predator odours from centrarchids affect the thermal tolerance of pugnose shiner and blackchin shiner, (2) explored how conspecific disturbance cues impacted blackchin shiner thermal tolerance and (3) quantified the thermal tolerance of two centrarchid species (largemouth bass (Micropterus nigricans) and pumpkinseed (Lepomis gibbosus)) predators and qualitatively compared this to the two shiner species. We found that blackchin shiner had a lower critical thermal maximum (CTMax) when given predator odours compared to a water control, demonstrating a plastic upper thermal limit in response to risk. In contrast, the CTMax of pugnose shiner did not differ between treatments, indicating that they may lack the capacity to respond to these concurrent stressors. The CTMax of blackchin shiner and pugnose shiner increased over the summer coinciding with increasing water temperature in their home habitat. However, when blackchin shiner received disturbance cue relative to the water control in a separate assay, the effect of seasonal acclimatization on CTMax was reduced. Finally, largemouth bass qualitatively exhibited a CTMax that was higher than the shiners, but pumpkinseed did not. Continuing to explore how predator–prey relationships change with warming waters may strengthen our predictive capacity when examining future climate‐change scenarios.

Keywords: blackchin shiner, CTMax, largemouth bass, pugnose shiner, pumpkinseed

1. INTRODUCTION

Warming is an important stressor that has the potential to impact all facets of an ectotherm's life. At the individual level, warming water can impact growth (Sandblom et al., 2016), morphology (Potts et al., 2021a) and metabolic rate (Nyboer & Chapman, 2018) of fishes. At the population level, warming has been documented to increase aggression in multiple fish species (Filipsson et al., 2023; Francispillai et al., 2024; Moffat et al., 2025) and to increase rates of intra‐guild predation (cannibalism) in three dragonfly species (Frances & McCauley, 2018). At the community level, with warming waters, some ectotherms have been observed to expand their range or increase in abundance, which can affect assemblage structure. For example, the range of centrarchid sportfishes including largemouth bass (Micropterus nigricans previously M. salmoides; Kim et al., 2022) and pumpkinseed (Lepomis gibbosus) in Ontario, Canada, has shifted northward over the last 30 years while the range of five minnow species (Leuciscidae) appears to have contracted southward (Alofs et al., 2014). As a result, predator–prey overlap in some ecosystems or microhabitats may be increasing with warming (Alofs et al., 2014).

With increased warming, predator–prey asymmetries may occur whereby predators and prey differ in their levels of performance, response rates and/or thermal tolerance (Dell et al., 2014; Kordas et al., 2011). The trophic‐sensitivity hypothesis posits that predators will be less tolerant than prey to environmental stress due to a combination of their greater body size, lower abundance and behavioural strategies like shifting habitat rather than persisting in situ potentially increasing adaptive capacity (Cheng et al., 2017). Support for the trophic‐sensitivity hypothesis has been shown in the fish (Mystus gulio)–shrimp (Penaeus monodon) predator–prey system whereby M. gulio exhibited decreased thermal tolerance and increased stress biomarkers under warming compared to the shrimp prey (Baag & Mandal, 2023). However, in a study of predator–prey thermal tolerance across 17 species of tadpole prey and 20 species of dragonfly predators, dragonfly predators were found to have a significantly higher critical thermal maximum (CTMax) than the tadpoles, which suggests that tadpoles, the prey, may be more vulnerable to warming (Pintanel et al., 2021).

In addition to the potential for mismatches in predator–prey environmental tolerances, predation pressure can also differ under warming due to increased foraging requirements, changes in attack speed and/or altered prey capture success (Dell et al., 2014). For example, Australian bass (Macquaria novemaculeata) increased their attack rates on eastern mosquitofish (Gambusia holbrooki) under warming, but eastern mosquitofish in turn increased their escape speed, exceeding the speed of the bass, resulting in a net decrease in predation pressure (Grigaltchik et al., 2012). As such, the dynamics of predator–prey interactions will likely shift under increased warming scenarios and, thus, the tolerances of both predators and prey to environmental stress should be considered in tandem to improve predictive capacity. However, studies on predation risk that require direct contact between predators and prey to monitor predation events may be limited by ethical implications or may not be possible when individuals are rare or of conservation importance (Crane et al., 2022).

One method that researchers can use to simulate predation risk non‐lethally is by using chemical risk cues. To assess their relative risk level in their microhabitat, prey can use chemical risk cues as a source of information to inform antipredator responses. For example, disturbance cues are a type of non‐damaged chemical cue released from startled conspecifics across the gill epithelia and in urine that can indicate to other nearby conspecifics the presence of danger (Crane et al., 2022). Predator odours (unique predator scent) or kairomones (combination of predator scent and by‐products of digestion, i.e., diet cues) are another class of risk cue released passively by a predator indicating its presence (Kasumyan, 2022; Mitchell et al., 2017). Both conspecific disturbance cues and predator odours have been documented to elicit antipredator behaviours in a number of aquatic prey species including the common minnow blackchin shiner (Miniellus heterodon; formerly in the Notropis genus; Groves et al., 2025b), Trinidadian guppy (Poecilia reticulata; Goldman et al., 2019; Pouca et al., 2021) and rainbow trout (Oncorhynchus mykiss; Ferrari et al., 2008; Vavrek & Brown, 2009). In this study, we explored how thermal tolerance was affected by chemical risk cues in pugnose shiner (Miniellus anogenus), a Threatened minnow under Canada's Species at Risk Act, and blackchin shiner, a non‐threatened congener of pugnose shiner. Notably, both pugnose shiner and blackchin shiner occupy similar ecological niches, are morphologically similar, often co‐occur in the same schools and are in the same genus, which makes comparisons between the two species highly ecologically relevant (Potts et al., 2021b; Reemeyer et al., 2024; unpublished catch data).

Pugnose shiner has been listed as Threatened by Canada's Species at Risk Act since 2013 (DFO, 2012). It has been documented in 15 locations in Canada, two of which are listed as having extirpated populations, and another eight of which are listed as having an unknown population status (DFO, 2012). Major threats to pugnose shiner include habitat modification, nutrient loading and turbidity; however, changes to trophic dynamics are also listed as a potential threat whose relative contribution to their imperilment is unknown in most of their range (DFO, 2012). Pugnose shiner may be impacted by expanding centrarchid populations that may increase competition with, or predation on this Threatened species (DFO, 2012). For example, bass occurrence is negatively associated with minnow diversity, with direct impacts of bass being predation on minnows and indirect impacts on minnows including habitat restriction (Jackson, 2002; Pilger et al., 2008; Schlosser, 1987). In addition, pumpkinseed is a potential predator of fish fry or eggs and a possible competitor of adult minnows due to shared diet items (e.g., macroinvertebrate larvae, zooplankton; Godinho et al., 1997; García‐Berthou & Moreno‐Amich, 2000). As such, understanding how acute exposure to predation risk impacts thermal tolerance may highlight how pugnose shiner will cope with warming waters and changing trophic dynamics compared to the non‐threatened blackchin shiner.

This study had three specific objectives. First, we explored whether predator odours from two centrarchid species (largemouth bass and pumpkinseed) affect the thermal tolerance of the Threatened pugnose shiner and the non‐imperilled blackchin shiner. We predicted that the thermal tolerance of the pugnose shiner may not be affected by centrarchid cue if they cannot recognize predator odours as sufficiently risky, which may potentially contribute to their lower abundance and imperilled status. In contrast, given that blackchin shiner is widespread, is non‐imperilled and has shown behavioural responses to predator odours in another study (Groves et al., 2025b), we predict that blackchin shiner will respond to centrarchid cue. Second, we explored how conspecific disturbance cues impacted blackchin shiner thermal tolerance. This was not done in pugnose shiner due to limited individuals available to produce conspecific cues. We predicted that blackchin shiner would show increased thermal tolerance when given conspecific disturbance cue relative to the control. This has been previously documented in a laboratory study; however, this has yet to be addressed in a natural setting (Groves et al., 2025a). Finally, we quantified the thermal tolerance of two centrarchid predators and/or competitors (cue donors for objective 1) of blackchin and pugnose shiner to explore a potential predator–prey mismatch in thermal tolerance. In accordance with the trophic‐sensitivity hypothesis, we predicted that centrarchid predators would exhibit decreased thermal tolerance relative to both minnows. Taken together, these objectives aim to highlight how blackchin and pugnose shiner may fare under concurrent warming and under greater predator risk as well as provide insight, more generally, into how predator–prey dynamics may be impacted by warming.

2. METHODS

2.1. Ethics statement

Ethics approval to perform this study was provided by the animal care committee at McGill University (animal use protocol number 7951) in accordance with the Canadian Councial for Animal Care. The following permits were obtained: Species at Risk Act permit (No. 24‐PCAA‐00010), the Ministry for Natural Resources of Ontario permits (No. 1105153) and permission from Pinery Provincial Park, Ontario, Canada.

2.2. Study site

This study took place in the Old Ausable Channel, Grand Bend, Ontario, Canada, May 27 – August 8, 2024. The Old Ausable Channel is a 14‐km long channel fed by ground and rainwater along the south shore of Lake Huron (Maun & Schincariol, 2010). Four imperilled fish species are found in the Old Ausable Channel: Threatened pugnose shiner; Endangered lake chubsucker (Erimyzon sucetta; Staton et al., 2009); and grass pickerel (Esox americanus vermiculatus; Beauchamp et al., 2012) and northern sunfish (Lepomis peltastes; DFO, 2024), which are listed as Special Concern. Blackchin shiner, largemouth bass and pumpkinseed are also found in the Old Ausable Channel in addition to other non‐imperilled fishes including blacknose shiner (Notropis heterolepis), yellow perch (Perca flavescens) and golden shiner (Notemigonus crysoleucas) (unpublished catch data).

2.3. Fish capture and holding

All fishes were captured using a seine (1‐cm mesh, 30 m length) deployed from a Jon boat. Fishes were immediately identified; bycatch was released at the site of capture, and target species were transferred to our channel‐side research trailer (43.290429°, −81.779460°) parked at the Huron Woods Community Center for holding and thermal tolerance trials. If fishes were to be used the following day for thermal tolerance trials (below), they were transferred to coolers equipped with battery‐operated bubblers and either rock or plant refugia (Chara spp.) and held overnight either in shoals for blackchin shiner, pugnose shiner and pumpkinseed, or alone for largemouth bass. If fish were to be used for the collection of chemical cues (below), they were placed immediately into their designated collection containers.

2.4. Chemical cue collection

Using a single fish at a time, one largemouth bass and four pumpkinseed were used as predator odour donors (Table 1). Donors were selected based on having a gape size that was large enough to theoretically allow them to prey upon blackchin and pugnose shiner (3 × 3 cm, largemouth bass; 1.23 ± 0.09 × 1.23 ± 0.05 cm, pumpkinseed; mean gape height × width ± standard error). We recorded the mass and standard length of the donor individuals, and they were placed in a collection cooler (45‐L cooler for largemouth bass, and 10‐L cooler for pumpkinseed) filled with channel water (27.1 L for largemouth bass, and between 3.2 and 4.5 L for pumpkinseed) such that the concentration of donor biomass per L of water per hour held was 0.8 g/L/h. This predator odour concentration was found to decrease CTMax in predator‐experienced P. multicolor (Groves et al., 2025c). In a previous study on blackchin shiner, this concentration of rock bass (another predator of blackchin shiner; Ambloplites rupestris) odour elicited an increase in shelter use relative to the control; however, the same concentration of pumpkinseed odour did not impact blackchin shiner behaviour (Groves et al., 2025b). It is important to note that in the Groves et al. (2025b) study, rock bass and pumpkinseed predator odour did not contain diet cues as both centrarchids were starved for 24 h before cue collection and were never fed blackchin shiner, demonstrating a weaker form of predation risk. In this current study, centrarchids were not starved before cue collection, likely releasing diet cues from prior feedings, to represent more ecologically relevant predator risk. The collection cooler contained a battery‐powered air bubbler and either a plastic plant or rock for refugia. We then left the donor undisturbed overnight before removing the donor the following day, placing them in a recovery cooler with fresh water and returning them to the channel. The temperature in the collection cooler for largemouth bass was 15.7°C and the mean temperature in the collection cooler for pumpkinseed was 19.0°C ± 1.5 (mean ± standard error). Cue‐collection temperatures varied due to different ambient temperatures associated with seasonal temperature change. The role of temperature in the release of and subsequent response to predator odours is relatively unknown (as reviewed in Kasumyan, 2022). The water in the collection cooler, hereafter ‘predator odour’, was then strained over poly‐fil fibre to catch any debris before being portioned and frozen at −20°C until use.

TABLE 1.

Biometric table for fish used for objectives 1, 2 and 3, as well as for cue (conspecific disturbance cues for blackchin shiner, and predator odour for pumpkinseed and largemouth bass) production.

Species Purpose N Mass ± standard error (g) Standard length ± standard error (cm)
Blackchin shiner Obj. 1 44 a 1.09 ± 0.07 3.99 ± 0.07
Obj. 2 30 1.37 ± 0.09 4.40 ± 0.12
Cue 30 1.50 ± 0.09 4.47 ± 0.08
Pugnose shiner Obj. 1 41 0.72 ± 0.03 3.54 ± 0.07
Pumpkinseed Obj. 3 20 22.30 ± 2.27 8.30 ± 0.27
Cue 4 77.25 ± 5.75 12.60 ± 0.16
Largemouth bass Obj. 3 10 b 48.00 ± 7.78 12.51 ± 0.82
Cue 1 520 31
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a

Three fish were not massed (scale died), but standard length was recorded.

b

One fish was not measured for mass or length.

Blackchin shiner was used to collect conspecific disturbance cues and undisturbed odour in three separate batches of 10 individuals following the procedure outlined in Groves et al. (2025a, 2025b), 151 (2025c) (Table 1). The mass and standard length of 10 donor individuals were recorded, and the donors were placed in a 10‐L cooler with 7.1–8.0 L of channel water. The volume was based on the total donor biomass such that the total concentration of conspecific disturbance cue was 2 g of donor fish per litre of collection water. This concentration of disturbance cue elicited an increase in activity in blackchin shiner relative to undisturbed odour (Groves et al., 2025b) and an increase in the critical thermal maximum (CTMax) of blackchin shiner that were given cue during CTMax trials relative to a water control (Groves et al., 2025a). The donor fish were held overnight in the collection cooler that contained a battery‐powered bubbler and plastic plant for enrichment. The following day, a portion of the collection cooler water was removed as our conspecific ‘undisturbed odour’. Then, the bubbler and plastic plant were carefully removed before simulating a 60‐s chase using a 15.24‐cm‐long plastic bass model glued to a plastic rod, making sure to not come into physical contact with the donor fish that could inadvertently release damage‐released alarm cues (Chivers & Smith, 1998). After the chase, fish were left for another 60 s before being removed from the collection cooler and placed into a recovery cooler prior to returning to the channel. We then recorded the temperature of the remaining collection cooler water (22.6°C ± 0.8; mean ± standard deviation), hereafter conspecific ‘disturbance cue’. The disturbance cue was removed from the cooler and strained over poly‐fil fibre to catch any debris. Then, both the disturbance cues and undisturbed odour were portioned and frozen at −20°C until use.

2.5. Experimental designs

For objective 1, 44 blackchin shiner and 41 pugnose shiner underwent thermal tolerance trials (below) while receiving 60 mL of either largemouth bass predator odour (n = 12 blackchin shiner, n = 15 pugnose shiner), pumpkinseed predator odour (n = 18 blackchin shiner, n = 14 pugnose shiner) or a channel‐water control (n = 14 blackchin shiner, n = 12 pugnose shiner) every 5 min throughout the trial (Table 1). Whenever possible, both blackchin shiner and pugnose shiner were run at the same time within a trial as they could receive the same chemical risk cues. One trial of three fish was removed from analyses as they were noted as appearing sick during the trial, as well as a single blackchin shiner that was identified as an outlier having reached CTMax 1.97°C lower (or 6.57 min earlier) than the next lowest CTMax, suggesting that the individual may have been ill. While we cannot know why the individuals were sick, the presence of parasites can be related to decreased thermal tolerance and survival, potentially confounding the results (Chrétien et al., 2023; De Bonville et al., 2024). As such, the sample sizes above are having removed those sick individuals.

For objective 2, 30 blackchin shiner underwent thermal tolerance trials, while receiving 60 mL of either conspecific disturbance cue (n = 18) or undisturbed (n = 12) odour every 5 min throughout the trial. As blackchin shiner were the only fishes receiving disturbance cue or undisturbed odour, they were only run with other blackchin shiner. Performing this objective with pugnose shiner was not possible due to insufficient fish caught in a single day to collect conspecific cues—out of the 38 days spent fishing for this study, on only two occasions were more than eight pugnose shiner caught on a single day.

For objective 3, 10 largemouth bass and 20 pumpkinseed underwent thermal tolerance trials without receiving chemical cues. Pumpkinseed and bass were not run within the same trial. Three pumpkinseed and two largemouth bass were removed from analyses due to either the presence of fungus or technical difficulties mid‐trial (the above sample sizes do not include these fish).

2.6. Thermal tolerance trials

The procedure for the thermal tolerance trials remained the same for all objectives. After the fishes were captured and held overnight, without food, as to be in a post‐absorptive state for testing, they were transferred to the thermal tolerance arena for their trial. Based on the fish's size, all blackchin shiner, pugnose shiner and pumpkinseed, and two of the largemouth bass were placed into one of three mesh baskets (15 cm l × 13 cm w × 12.5 cm h) within a Plexi‐glass chamber (61 cm l × 30.5 cm w × 20.3 cm h). As such, up to three fish could be ran in a single trial, and each basket was covered with corrugated board along three sides so that the individual within a box could not view a neighbouring fish. As the remaining either largemouth bass were too large for the mesh baskets, they were either ran in half the Plexi‐glass chamber (~30 cm h × 30.5 cm w × 20.3 cm h) by dividing the whole chamber with a mesh barrier, or in the whole chamber separated from the heater with a mesh barrier (~45 cm l × 30.5 w cm × 20.3 cm h). Regardless if the fish were placed into a mesh basket or into a portion of the arena directly, the arena was filled with channel water and contained an airstone and circulating heater (Julabo Corio CD, www.julabo.com). The channel water in the arena was within approximately ±1°C of the cooler water in which fish were held overnight, and the channel‐water temperature was recorded prior to the thermal tolerance trial (hereafter ‘environmental temperature’; Figure S1). The fish were given one hour to habituate to the thermal tolerance arena prior to the start of the trial. Then, the water temperature was increased at a constant rate of 0.3°C/min (Becker & Genoway, 1979). We recorded the critical thermal maxima (CTMax) of each individual as the water temperature at which a fish lost equilibrium for three seconds. We also recorded the agitation temperature (T Ag) as the temperature at which a fish first showed behavioural avoidance in response to warming (McDonnell & Chapman, 2015)—specifically a dive in the corner of the thermal tolerance basket for the fishes tested here. After a fish reached their CTMax, they were removed from the thermal tolerance arena and placed into aerated, ambient temperature water in a recovery cooler before being returned to the channel. As in Raby et al. (2025), details for thermal tolerance trials can be found in Table S1.

2.7. Statistical analysis

All analyses were run using R Studio (version 2024.04.1; R Core Team, 2024) with packages emmeans v. 1.10.2 (Lenth, 2024), lmerTest v. 3.1.3 (Kuznetsova et al., 2017), multcomp v. 1.4.25 (Hothorn et al., 2008), multcompView v. 0.1.10 (Graves et al., 2024), MuMIn v. 1.47.5 (Bartoń, 2023) and tidyverse v. 2.0.0 (Wickham et al., 2019).

For objective 1, we analysed CTMax and T Ag in separate linear models. Each model included species (blackchin shiner vs. pugnose shiner), risk stimulus (largemouth bass predator odour vs. pumpkinseed predator odour vs. channel water) and environmental temperature as fixed effects. Environmental temperature was always included as prior work has shown that both blackchin and pugnose shiner exhibit seasonal variation in thermal tolerance (Reemeyer et al., 2024). Then, using corrected Akaike information criterion (AICc) comparisons, we explored including log‐transformed body mass as an additional fixed effect and trial number as a random effect. When interactions between fixed effects were not significant, we removed them via the backwards method. When interactions including species were present, we split our model by species to further explore the impacts of risk stimuli on blackchin and pugnose shiner thermal tolerance. When risk stimulus was significant, we performed a Tukey honest significant differences test for pairwise comparisons between groups. The assumptions for homoscedasticity of residuals and normality of residuals were verified and confirmed visually.

For objective 2, we ran separate linear models for blackchin shiner CTMax and T Ag with risk stimuli (conspecific disturbance cue vs. undisturbed odour) and environmental temperature as fixed effects. We used AICc comparisons to explore whether to include log‐transformed mass as a fixed effect and trial number as a random effect. When interactions were not significant between fixed effects, they were removed stepwise as above. The assumptions for homoscedasticity of residuals and normality of residuals were verified and confirmed visually.

For objective 3, we analysed differences in CTMax and T Ag of pumpkinseed and largemouth bass using linear models. Species and environmental temperature were included as fixed effects. As above, we used AICc comparisons to explore whether to include log‐transformed body mass as an additional fixed effect and trial number as a random effect. When interactions between fixed effects were not significant, we removed them via the backwards method. The assumptions for homoscedasticity of residuals and normality of residuals were verified and confirmed visually.

3. RESULTS

3.1. Objective 1: Impacts of predator odour on blackchin and pugnose shiner

For CTMax, the best fit model was a simple linear model with risk stimulus, species, environmental temperature and the interaction between risk stimulus and species (p = 0.04; Table 2). For blackchin shiner, both risk stimulus (p < 0.001) and environmental temperature (p = 0.006) were significant (Table 2). When blackchin shiner were given channel water, they had a significantly higher CTMax than when given largemouth bass predator odour (p = 0.047; Table S2) or pumpkinseed odour (p = 0.027; Table S2; Figure 1a). In addition, as environmental temperatures increased, CTMax also increased (Figure 2a). For pugnose shiner, environmental temperature was significant (p = 0.009), but risk stimulus (p = 0.69) was not (Table 1). When pugnose shiner received channel water, largemouth bass odour or pumpkinseed odour, their upper thermal limit did not differ (Figure 1b). As with blackchin shiner, CTMax increased with environmental temperature (Figure 2a).

TABLE 2.

Results from separate linear models or linear mixed models on metrics of thermal tolerance (critical thermal maximum, CTMax; agitation temperature, T Ag) for blackchin shiner and pugnose shiner.

Metric Data Fixed effects Sum of squares Mean sum of squares Df F value p Value
CTMax All Risk stimulus 13.04 6.52 2 10.93 <0.001
Species 1.39 1.39 1 2.33 0.13
Environmental temperature 11.76 11.76 1 19.72 <0.001
Risk stimulus: species 3.89 1.94 2 3.56 0.04
Residuals 46.53 0.60 78
Blackchin Risk stimulus 18.48 9.24 2 14.23 <0.001
Environmental temperature 5.50 5.50 1 8.48 0.006
Residuals 25.96 25.96 40
Pugnose Risk stimulus 0.42 0.21 2 0.37 0.69
Environmental temperature 4.24 4.24 1 7.63 0.009
Residuals 20.56 0.56 37
T Ag All Risk stimulus 10.19 5.09 2, 22.37 0.46 0.63
Species 60.63 60.63 1, 63.16 5.52 0.02
Environmental temperature 78.39 78.39 1, 23.67 7.14 0.01
Log mass 15.15 15.15 1, 65.93 1.38 0.24
Environmental temperature: species 45.75 45.75 1, 64.23 4.17 0.045
Blackchin Risk stimulus 96.39 48.20 2, 16.94 5.31 0.02
Environmental temperature 37.20 37.20 1, 19.87 4.09 0.06
Log mass 1.67 1.67 1, 27.88 0.18 0.67
Environmental temperature: risk stimulus 90.69 45.34 2, 17.22 4.99 0.02
Risk stimulus: log mass 65.09 32.55 2, 28.48 3.58 0.04
Pugnose Risk stimulus 0.13 0.07 2, 15.33 0.009 0.99
Environmental temperature 49.52 49.52 1, 15.89 6.52 0.02
Log mass 3.56 3.56 1, 33.93 0.47 0.50
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Note: Models include risk stimulus (channel water control vs. largemouth bass odour vs. pumpkinseed odour), species (blackchin shiner vs. pugnose shiner) as fixed effects and environmental temperature as a covariate. When indicated by the best fit model, trial number was included as a random effect. Significant values (p < 0.05) are shown in bold.

FIGURE 1.

FIGURE 1

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Critical thermal maximum (CTMax, open circles) and agitation temperature (T Ag, closed circles) of blackchin shiner (panel a) and pugnose shiner (panel b) when given risk cues from either channel water, largemouth bass odour or pumpkinseed odour. Data are shown as means ± standard error, and raw data are underlaid. Lower case letters indicate Tukey honest significant differences between groups.

FIGURE 2.

FIGURE 2

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Relationships between environmental channel temperature at the time of the thermal tolerance trial and critical thermal maximum (CTMax, open circles, panel a) and agitation temperature (T Ag, closed circles, panel b) of blackchin shiner (blue) and pugnose shiner (orange) grouped across risk cues. Note that blackchin shiner are not in panel b due to interactions between risk cues and environmental temperature (see Figure 3). Relationships are shown with 95% confidence intervals (grey), and raw data are underlaid. Note the different y axis values.

For T Ag, the best fit model included risk stimulus, species, environmental temperature, log‐transformed mass and the interaction between environmental temperature and species (p = 0.045). For blackchin shiner, there was a significant interaction between environmental temperature and risk stimulus (p = 0.02; Table 2), and risk stimulus and log‐transformed mass (p = 0.04; Table 2). When given predator odour from largemouth bass, T Ag increased with fish mass, whereas, when given channel water or pumpkinseed predator odours, T Ag decreased with fish mass (Table 3a). When given largemouth bass predator odour, the T Ag of blackchin shiner decreased with environmental temperature, whereas, when given channel water, T Ag increased (Figure 3b). For pugnose shiner, only environmental temperature was significant (p = 0.02; Table 2), and T Ag increased with environmental temperature (Figure 2b).

TABLE 3.

Results from a linear model for critical thermal maximum (CTMax) and linear mixed model results for agitation temperature (T Ag) of blackchin shiner when given conspecific disturbance cue or undisturbed odour.

Metric Fixed effect Sum of squares Mean sum of squares Df F value p Value
CTMax Risk stimuli 0.40 0.40 1 0.41 0.528
Environmental temperature 4.27 4.27 1 4.35 0.048
Risk stimuli: environmental temperature 4.31 4.31 1 4.40 0.047
Residuals 22.54 0.98 23
T Ag Risk stimuli 1.62 1.62 1, 4.85 0.11 0.750
Environmental temperature 11.07 11.07 1, 5.01 0.78 0.418
Log mass 16.64 16.64 1, 21.95 1.17 0.291
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Note: For CTMax environmental temperature was included as a covariate. For T Ag, environmental temperature and log‐transformed mass were included as covariates and trial number as a random effect. Significant values (p < 0.05) are shown in bold.

FIGURE 3.

FIGURE 3

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Relationships between agitation temperature (T Ag) and log‐transformed mass (g; panel a) and environmental channel temperature at the time of the thermal tolerance trial (panel b) of blackchin shiner given channel water (blue), largemouth bass odour (red) or pumpkinseed odour (yellow). Relationships are shown with 95% confidence intervals (grey), and raw data are underlaid. Note the different y axis values due to the confidence intervals.

3.2. Objective 2: Impacts of conspecific disturbance cue on blackchin shiner

When exploring the impacts of conspecific disturbance cue vs. undisturbed odour on blackchin shiner CTMax, the best fit model was a simple linear model with risk stimuli and environmental temperature as fixed effects (Table 3). Risk stimulus alone was not significant (p = 0.53; Table 3; Figure 4a). However, there was a significant interaction between risk stimuli and environmental temperature (p = 0.047). The CTMax of blackchin shiner showed a greater increase with environmental temperature when given undisturbed odour versus disturbance cue (Figure 4b).

FIGURE 4.

FIGURE 4

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Thermal tolerance of blackchin shiner when given either conspecific disturbance cues (red) or undisturbed odour (green). Panel a shows the critical thermal maximum (CTMax, closed circles) and agitation temperature (T Ag, open circles). Data are shown as means ± standard error, and raw data are underlaid. Panel b shows the relationship between critical thermal maximum (CTMax) and environmental temperature for blackchin shiner given conspecific disturbance cue (red) or an undisturbed odour control (green). Relationships are shown with 95% confidence intervals (grey), and raw data are underlaid.

For TAg, our best fit model was a linear mixed model with risk stimuli, environmental temperature and log‐transformed body mass as fixed effects and trial number as a random effect. Neither risk stimuli (p = 0.75), environmental temperature (p = 0.42) or log‐transformed body mass (p = 0.29) were significant (Table 3). As such, the temperature at which individuals first became agitated did not differ when given risk cues versus the undisturbed odour control (Figure 4a).

3.3. Objective 3: Centrarchid thermal tolerance

The best fit model for CTMax of largemouth bass and pumpkinseed was a simple linear model including species and environmental temperature as fixed effects. Species was not significant (p = 0.45; Table 4); there was no difference in CTMax between largemouth bass and pumpkinseed (Figure 5a). Environmental temperature was significant (p < 0.001; Table 4); CTMax increased with environmental temperature (Figure 5b).

TABLE 4.

Linear model for critical thermal maximum (CTMax) and linear mixed model for agitation temperature (T Ag) of largemouth bass vs. pumpkinseed.

Metric Fixed effect Sum of squares Mean sum of squares Df F value p Value
CTMax Species 0.53 0.53 1 0.59 0.45
Environmental temperature 31.26 31.26 1 34.89 <0.001
Residuals 52.91 0.58 91
TAg Species 15.04 15.04 1, 18.64 0.74 0.40
Environmental temperature 69.92 69.92 1, 19.04 3.46 0.08
Log mass 7.61 7.61 1, 23.05 0.38 0.54
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Note: Environmental temperature was included as covariate for both CTMax and T Ag. For T Ag, log‐transformed mass was included as an additional covariate, and trial was included as a random effect. Significant values (p < 0.05) are shown in bold.

FIGURE 5.

FIGURE 5

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Thermal tolerance metrics of largemouth bass (red) and pumpkinseed (yellow). Panel a shows the critical thermal maximum (CTMax, open circles) and agitation temperature (T Ag, closed circles) as means ± standard error with the raw data underlaid. Panel b shows the relationship between CTMax and environmental temperature with 95% confidence intervals (grey).

The best fit model for T Ag was a linear mixed model with species (largemouth bass vs. pumpkinseed), environmental temperature and log‐transformed body mass as fixed effects, and trial as a random effect. Neither species (p = 0.40), nor log‐transformed mass (p = 0.54) were significant, but there was a weak effect of environmental temperature (p = 0.08; Table 4).

4. DISCUSSION

To understand impacts of predation risk on thermal tolerance, we conducted a series of three field experiments. We found that blackchin shiner given predator odour from either largemouth bass or pumpkinseed had a significantly lower CTMax than blackchin shiner given a channel‐water control. However, pugnose shiner CTMax did not differ when given predator odour from largemouth bass or pumpkinseed, or the channel‐water control. When blackchin shiner were given conspecific disturbance cues during thermal tolerance trials, CTMax increased less with increasing environmental temperatures than when given the control, which suggests that the effect of seasonal acclimatization on CTMax is reduced when given disturbance cue during CTMax trials. Further, largemouth bass qualitatively exhibited a CTMax that was higher than the shiners, but pumpkinseed did not. Together, these results suggest that pugnose shiner may perceive and/or lack the capacity to respond to concurrent dual stressors of predation risk and warming during thermal tolerance trials, whereas blackchin shiner upper thermal limits are plastic when receiving risk cues.

4.1. Objective 1: Impacts of predator odour on blackchin and pugnose shiner

When blackchin shiner were given predator odours from either largemouth bass or pumpkinseed, they exhibited significantly lower CTMax than when given the channel‐water control. A decreased CTMax in response to predator odours suggests that blackchin shiner perceive predator odours as stressful. The General Stress Paradigm posits that under predation risk, prey increase their metabolic rate to prepare for an escape response, thereby diverting energy away from other activities (Hawlena & Schmitz, 2010; Janssens et al., 2015). As such, exhibiting a stress response to predator odours can convey an antipredator advantage by cueing to receivers to mount an escape response. However, as a result of detecting predator odours under increased temperatures, as shown in this experiment, prey may be more vulnerable to climate warming due to decreased CTMax. Perhaps then, increased predation risk and warming have the potential for additive or synergistic interactions on prey minnows.

Decreased CTMax in response to predator odours in blackchin shiner aligns with results of a field experiment where predator‐experienced P. multicolor that received predator odours from African sharptooth catfish (Clarias gariepinus) showed lower CTMax compared to when receiving a lake‐water control (Groves et al., 2025c). However, in a study on grey treefrog tadpoles (Hyla versicolor), chronic exposure to predator odours from dragonfly nymph (Anax junius) resulted in an increased CTMax compared to tadpoles that lacked predator odour exposure (Katzenberger et al., 2014). Additionally, in a laboratory experiment on blackchin shiner, acute exposure to rock bass predator odour elicited an antipredator response, but did not impact CTMax (Groves et al., 2025a). These three contrasting trends on the impacts of predator odours on thermal tolerance suggest that impacts of risk cues on upper thermal limits are context dependent. This is not surprising given that behavioural responses to predation risk can depend on the individual (e.g., personality; Dall et al., 2004; Haines et al., 2020); sex (Brusseau et al., 2023; Ingley et al., 2014); size (Reinhardt & Healey, 1997); abiotic environmental conditions (temperature (Briceño et al., 2020); hypoxia (Strand et al., 2022); turbidity (Abrahams & Kattenfeld, 1997; Kimbell & Morrell, 2015)); biotic environmental conditions (background levels of predation risk (Brown et al., 2006; Chivers et al., 2014); presence of parasites (Barber et al., 2000; Demandt et al., 2018)); as well spatio‐temporal variation in environmental conditions (uncertainty (Feyten et al., 2019); habitat complexity (Crane et al., 2020; Rilov et al., 2007); and, variation in risk (Lima & Bednekoff, 1999; Zanette & Clinchy, 2019)). Therefore, individuals must continuously balance the need to satisfy energetic demands (e.g., foraging, mating, defence) with avoiding predation to exhibit adaptive behavioural and physiological responses to ecological conditions based on their internal and external environment (Lima & Bednekoff, 1999; Schmitz & Trussell, 2016).

In contrast, pugnose shiner did not differentiate between either predator odours or the channel‐water control in their upper thermal limits. Differing responses to predator odours on CTMax in Threatened pugnose shiner vs. non‐threatened blackchin shiner are interesting as both species are in the same genus, often co‐occur and are morphologically similar (Potts et al., 2021b). Further, in the Old Ausable Channel, individuals from both species are caught in the same seines. Pugnose shiner not exhibiting a reduced CTMax when given predator odours while blackchin shiner do may indicate that both shiners perceive and/or respond to risk cues differently in a multiple stressor context. There are several potential reasons along the information‐decision pipeline, that may act in isolation or interact, to explain why pugnose shiner may fail to exhibit the same response to predator odours as blackchinhiner (Schmidt et al., 2010). For example, pugnose shiner may not respond to predator odours if they first fail to detect predator odours along the chemosensory pathway (Schmidt et al., 2010; Wisenden, 2015). Second, pugnose shiner may fail to perceive predator odours as indicating risk, that is, detecting the presence of largemouth bass but not associating the presence of largemouth bass with danger. Finally, pugnose shiner may fail to respond to predator odours either because they do not perceive their current level of danger as high enough to warrant a response (exhibiting a threat‐sensitive antipredator response; Brown et al., 2011), or they perceive the concurrent threat from warming during the thermal tolerance trial to be a more pressing stressor. Taken together, the difference between the status of the non‐threatened blackchin shiner and Threatened pugnose shiner may be in part due to different perceptions or use of risk information.

Blackchin shiner showed a reduced CTMax when given pumpkinseed odour relative to the channel‐water control in this study but did not exhibit antipredator behaviours in response to pumpkinseed odour in a prior study (Groves et al., 2025b). These contrasting findings may demonstrate that blackchin shiner lack an innate antipredator response to pumpkinseed and instead rely on information from diet cues to assess their relative risk level. Given that in this current study, pumpkinseed were not starved before cue collection, it is possible that whatever diet cues released from donors conveyed a greater level of predation risk to blackchin shiner receivers. Future studies should perform donor stomach‐content analysis in conjunction with behavioural assays to clarify the role of diet cues in prey assessment of risk. In a natural setting, it is unlikely that predators would typically release predator odours without diet cues, so predator odours alone may be less ecologically relevant.

Interestingly, as blackchin shiner size increased, T Ag increased when given largemouth bass odour, a trend that has also been documented in the African cichlid, P. multicolor in response to predator odour (Groves et al., 2025c). In comparison, when individuals received pumpkinseed predator odour, T Ag decreased with increased fish size, mirroring the trend seen with the water control. It is possible that smaller blackchin shiner perceive pumpkinseed cue as more relevant risk than larger individuals as when pumpkinseed include fish in their diet, it typically is fry or eggs, not full‐sized individuals (García‐Berthou & Moreno‐Amich, 2000; Godinho et al., 1997). It is also possible that blackchin shiner perceive pumpkinseed odour in general to be less risky than largemouth bass predator odour, since decreased TAg with increased blackchin shiner size was also seen with the water control, yet individuals still showed reduced CTMax when given pumpkinseed odour. This suggests that when blackchin shiner received pumpkinseed predator odour, individuals exhibit increased vigilance rather than an escape response; however, additional research is needed to disentangle if blackchin shiner are responding to pumpkinseed as predators or as competitors. The use of chemical cues to detect, perceive and respond to possible interspecific competitors in aquatic ecosystems has received considerably less attention compared to predation. However, four species of coral‐reef damselfish (Coppock et al., 2016), and spiny lobster (Panulirus argus; Behringer & Hart, 2017) are documented to exhibit an avoidance response to chemical cues from heterospecific competitors.

4.2. Objective 2: Impacts of conspecific disturbance cue on blackchin shiner

We found that acute exposure to conspecific disturbance cues in channel‐side thermal tolerance assays in blackchin shiner did not result in an absolute change in CTMax relative to when given the control but instead yielded a weaker increase in CTMax (ranging from 36.36 to 37.93°C; minimum – maximum values) with environmental temperatures ranging 21.2–23.7°C. In contrast, when blackchin shiner were given undisturbed odour, CTMax increased more sharply (ranging 34.52–38.63°C; minimum–maximum values) with environmental temperatures ranging 21.3–22.9°C. This differs from a previous study on blackchin shiner acclimated to 18°C where acute exposure to conspecific disturbances cues elicited a significantly higher CTMax than when they were given either no cue or rock bass predator odour during thermal tolerance trials (Groves et al., 2025a). In the same study, CTMax was not altered by conspecific disturbance cues in 25°C acclimated fish (Groves et al., 2025a), perhaps due to a limited ability to adjust upper limits under higher temperatures due to physiological constraints (i.e., warming as a concrete ceiling; Sandblom et al., 2016). Further, the thermal tolerance of blackchin shiner was documented to increase with environmental temperatures aligned with seasonal acclimatization in a previous field study in the Old Ausable Channel (Reemeyer et al., 2024). In this study, the benefit of increased thermal tolerance conferred by seasonal acclimatization may be reduced when given acute exposure to disturbance cue in channel‐side assays.

4.3. Objective 3: Centrarchid thermal tolerance

Based on the trophic‐sensitivity hypothesis, we predicted that largemouth bass and pumpkinseed would show reduced CTMax compared to blackchin and pugnose shiner. We could not test this statistically as the shiners had received cues (e.g., channel water, predator odour) during the trial, and the centrarchids were tested without cues. However, we can draw some inferences regarding potential predator–prey asymmetries. Both shiners receiving chemical cues and centrarchids being tested undisturbed show an increase in CTMax with environmental temperature, demonstrating that both shiners and centrarchids can exhibit plasticity in thermal tolerance. While largemouth bass and pumpkinseed CTMax did not significantly differ from one another, seven of the 10 largemouth bass showed higher CTMax values than the maximum CTMax (38.13°C) of the shiners. While this difference requires empirical testing, our findings may suggest that largemouth bass is more tolerant to warming than the shiners, contrary to the trophic‐sensitivity hypothesis and highlighting a potential predator–prey asymmetry in the face of global warming. Further, it is unknown how the thermal tolerance of both centrarchid predators/competitors is impacted by the presence of shiner cue—would the odour of a prey item result in an earlier T Ag due to prey‐seeking behaviour, and would this translate to decreased energy availability as they approach their upper thermal limit? Including prey cues thus represents a logical next step in testing the thermal tolerance of fish communities as a whole. Social context is often overlooked when studying animal physiology, which may result in either over‐ or under‐estimated physiological values (Killen et al., 2026). Failing to consider species interactions in evaluating predator–prey thermal tolerances then may potentially distort our understanding of an animal's tolerance to warming. It is also worth noting that a subset of individuals was removed from analyses due to the presence of fungus or illness. In nature, it is likely then that immune costs associated with illness compromise performance (Chrétien et al., 2023), which could potentially further impact species interactions under warming and should be investigated further.

5. CONCLUSION

In conclusion, blackchin shiner and pugnose shiner respond to predator odours during thermal tolerance trials differently, with pugnose shiner reacting similarly to predator odours and the channel‐water control. Both shiners were able to increase their upper thermal limits with seasonal temperature increases; however, blackchin shiner given disturbance cues showed a weaker increase in CTMax with seasonal warming. Finally, largemouth bass qualitatively showed higher thermal tolerance than both shiners, which suggests that under future climate warming, predators and prey may face thermal asymmetries. These findings suggest that increases in centrarchid predator populations in northern parts of their range may negatively affect the Threatened pugnose shiner and highlight the importance of integrating biotic and abiotic stressors when evaluating risk factors for imperilled fishes.

AUTHOR CONTRIBUTIONS

Conceptualization by VG, NEM and LJC. Data curation by VG, MM and LN. Visualization, formal analysis and writing – original draft by VG. Resources by LJC and NEM. All authors reviewed the manuscript.

FUNDING INFORMATION

Funding was provided by the Department of Fisheries and Oceans Canada Nature Fund for Aquatic Species at Risk (G253657) to LJC.; Distinguished James McGill Professorship Research Funds to LJC.; doctoral scholarships/fellowships from NSERC, the Fonds de Recherche du Québec Nature et technologies (10.69777/330366), and McGill University to VG; and a NSERC undergraduate summer research award to MM.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflicts of interest.

Supporting information

Figure S1 Environmental temperature taken before each thermal tolerance trial across the testing dates. Raw data are underlaid and the grey shading shows 95% confidence intervals.

Table S1: Modified table from Raby et al. (2025) with details for the thermal tolerance trials.

Table S2: Comparisons between stimuli for blackchin shiner critical thermal maximum (CTMax) via Tukey honest significant differences. Significant values (p < 0.05) are shown in bold.

JFB-109-1786-s001.docx (135.8KB, docx)

ACKNOWLEDGEMENTS

We thank Julia Wein for assistance with fish capture, Dr. Trevor Pitcher for the use of his research trailer, and the Huron Woods Community Center and Pinery Provincial Park for their hospitality. We also thank two anonymous reviewers for their constructive feedback.

DATA AVAILABILITY STATEMENT

Data and code will be available at the following upon publication: 10.6084/m9.figshare.32030136.

REFERENCES

  1. Abrahams, M. , & Kattenfeld, M. (1997). The role of turbidity as a constraint on predator‐prey interactions in aquatic environments. Behavioral Ecology and Sociobiology, 40, 169–174. [Google Scholar]
  2. Alofs, K. M. , Jackson, D. A. , & Lester, N. P. (2014). Ontario freshwater fishes demonstrate differing range‐boundary shifts in a warming climate. Diversity and Distributions, 20, 123–136. [Google Scholar]
  3. Baag, S. , & Mandal, S. (2023). Do predator (Mystus gulio) and prey (Penaeus monodon) have differential response against heatwaves? Unveiling through oxidative stress biomarkers and thermal tolerance estimation. Marine Environmental Research, 184, 105850. [DOI] [PubMed] [Google Scholar]
  4. Barber, I. , Hoare, D. , & Krause, J. (2000). Effects of parasites on fish behaviour: A review and evolutionary perspective. Reviews in Fish Biology and Fisheries, 10, 131–165. [Google Scholar]
  5. Bartoń, K. (2023). MuMIn: Multi‐Model Inference. https://CRAN.R-project.org/package=MuMIn
  6. Beauchamp, J. , Boyko, A. L. , Dunn, S. , Hardy, D. , Jarvis, P. L. , & Staton, S. K. (2012). Management plan for the grass pickerel (Esox americanus vermiculatus) in Canada. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada. [Google Scholar]
  7. Becker, C. D. , & Genoway, R. G. (1979). Evaluation of the critical thermal maximum for determining thermal tolerance of freshwater fish. Environmental Biology of Fishes, 4, 245–256. [Google Scholar]
  8. Behringer, D. C. , & Hart, J. E. (2017). Competition with stone crabs drives juvenile spiny lobster abundance and distribution. Oecologia, 184, 205–218. [DOI] [PubMed] [Google Scholar]
  9. Briceño, F. A. , Fitzgibbon, Q. P. , Polymeropoulos, E. T. , Hinojosa, I. A. , & Pecl, G. T. (2020). Temperature alters the physiological response of spiny lobsters under predation risk. Conservation Physiology, 8, coaa065. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Brown, G. E. , Ferrari, M. C. O. , & Chivers, D. P. (2011). Learning about danger: Chemical alarm cues and threat‐sensitive assessment of predation risk by fishes. Fish Cognition and Behavior. Blackwell Publishing Ltd. [Google Scholar]
  11. Brown, G. E. , Rive, A. C. , Ferrari, M. C. O. , & Chivers, D. P. (2006). The dynamic nature of antipredator behavior: Prey fish integrate threat‐sensitive antipredator responses within background levels of predation risk. Behavioral Ecology and Sociobiology, 61, 9–16. [Google Scholar]
  12. Brusseau, A. J. P. , Feyten, L. E. A. , Groves, V. , Felismino, M. E. L. , Cao Van Truong, D. , Crane, A. L. , Ramnarine, I. W. , & Brown, G. E. (2023). Sex and background risk influence responses to acute predation risk in Trinidadian guppies. Behavioral Ecology, 34, 898–906. [Google Scholar]
  13. Cheng, B. S. , Komoroske, L. M. , & Grosholz, E. D. (2017). Trophic sensitivity of invasive predator and native prey interactions: Integrating environmental context and climate change. Functional Ecology, 31, 642–652. [Google Scholar]
  14. Chivers, D. P. , McCormick, M. I. , Mitchell, M. D. , Ramasamy, R. A. , & Ferrari, M. C. O. (2014). Background level of risk determines how prey categorize predators and non‐predators. Proceedings of the Royal Society B‐Biological Sciences, 281, 20140355. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Chivers, D. P. , & Smith, R. J. F. (1998). Chemical alarm signalling in aquatic predator‐prey systems: A review and prospectus. Ecoscience, 5, 338–352. [Google Scholar]
  16. Chrétien, E. , De Bonville, J. , Guitard, J. , Binning, S. A. , Melis, É. , Kack, A. , Côté, A. , Gradito, M. , Papillon, A. , Thelamon, V. , Levet, M. , & Barou‐Dagues, M. (2023). Few studies of wild animal performance account for parasite infections: A systematic review. Journal of Animal Ecology, 92, 794–806. [DOI] [PubMed] [Google Scholar]
  17. Coppock, A. G. , Gardiner, N. M. , & Jones, G. P. (2016). Sniffing out the competition? Juvenile coral reef damselfishes use chemical cues to distinguish the presence of conspecific and heterospecific aggregations. Behavioural Processes, 125, 43–50. [DOI] [PubMed] [Google Scholar]
  18. Crane, A. L. , Bairos‐Novak, K. R. , Goldman, J. A. , & Brown, G. E. (2022). Chemical disturbance cues in aquatic systems: A review and prospectus. Ecological Monographs, 92, e01487. [Google Scholar]
  19. Crane, A. L. , Ferrari, M. C. O. , Rivera‐Hernandez, I. A. E. , & Brown, G. E. (2020). Microhabitat complexity influences fear acquisition in fathead minnows. Behavioral Ecology, 31, 261–266. [Google Scholar]
  20. Dall, S. R. X. , Houston, A. I. , & McNamara, J. M. (2004). The behavioural ecology of personality: Consistent individual differences from an adaptive perspective. Ecology Letters, 7, 734–739. [Google Scholar]
  21. De Bonville, J. , Côté, A. , & Binning, S. A. (2024). Thermal tolerance and survival are modulated by a natural gradient of infection in differentially acclimated hosts. Conservation Physiology, 12, coae015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Dell, A. I. , Pawar, S. , & Savage, V. M. (2014). Temperature dependence of trophic interactions are driven by asymmetry of species responses and foraging strategy. Journal of Animal Ecology, 83, 70–84. [DOI] [PubMed] [Google Scholar]
  23. Demandt, N. , Saus, B. , Kurvers, R. H. J. M. , Krause, J. , Kurtz, J. , & Scharsack, J. P. (2018). Parasite‐infected sticklebacks increase the risk‐taking behaviour of uninfected group members. Proceedings of the Royal Society B: Biological Sciences, 285, 20180956. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. DFO . (2012). Recovery Strategy for the Pugnose Shiner (Notropis anogenus) in Canada, 2012.
  25. DFO . (2024). Management plan for the northern sunfish (Lepomis peltastes) in Canada (Great Lakes – Upper St. Lawrence populations). Species at Risk Act Management Plan Series. Fisheries and Oceans Canada. [Google Scholar]
  26. Ferrari, M. C. O. , Messier, F. , & Chivers, D. P. (2008). Can prey exhibit threat‐sensitive generalization of predator recognition? Extending the predator recognition continuum hypothesis. Proceedings of the Royal Society B: Biological Sciences, 275, 1811–1816. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Feyten, L. E. A. , Demers, E. E. E. M. , Ramnarine, I. W. , Chivers, D. P. , Ferrari, M. C. O. , & Brown, G. E. (2019). Who's where? Ecological uncertainty shapes neophobic predator avoidance in Trinidadian guppies. Behavioral Ecology and Sociobiology, 73, 70. [Google Scholar]
  28. Filipsson, K. , Bergman, E. , Erlandsson, A. , Greenberg, L. , Österling, M. , & Watz, J. (2023). Temperature during embryonic development in brown trout influences juvenile behaviour in encounters with predators. Journal of Zoology 322, 241–250. [Google Scholar]
  29. Frances, D. N. , & McCauley, S. J. (2018). Warming drives higher rates of prey consumption and increases rates of intraguild predation. Oecologia, 187, 585–596. [DOI] [PubMed] [Google Scholar]
  30. Francispillai, E. K. , Dietsch, S. , & Chapman, L. J. (2024). Effects of temperature on fish aggression and the combined impact of temperature and turbidity on thermal tolerance. Journal of Thermal Biology, 125, 103987. [DOI] [PubMed] [Google Scholar]
  31. García‐Berthou, E. , & Moreno‐Amich, R. (2000). Food of introduced pumpkinseed sunfish: Ontogenetic diet shift and seasonal variation. Journal of Fish Biology, 57, 29–40. [Google Scholar]
  32. Godinho, F. , Ferreira, M. T. , & Cortes, R. V. (1997). The environmental basis of diet variation in pumpkinseed sunfish, Lepomis gibbosus, and largemouth bass, Micropterus salmoides, along an Iberian river basin. Environmental Biology of Fishes, 50, 105–115. [Google Scholar]
  33. Goldman, J. A. , Singh, A. , Demers, E. E. M. , Feyten, L. E. A. , & Brown, G. E. (2019). Does donor group size matter? The response of guppies (Poecilia reticulata) and convict cichlids (Amatitlania nigrofasciata) to disturbance cues from conspecific and heterospecific donors. Canadian Journal of Zoology, 97, 319–325. [Google Scholar]
  34. Graves, S. , Hans‐Peter, P. , & Selzer, L. (2024). multcompView: Visualizations of paired comparisons. https://CRAN.R-project.org/package=multcompView
  35. Grigaltchik, V. S. , Ward, A. J. W. , & Seebacher, F. (2012). Thermal acclimation of interactions: Differential responses to temperature change alter predator–prey relationship. Proceedings of the Royal Society B: Biological Sciences, 279, 4058–4064. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Groves, V. , Brabant, C. , Boys, M. , & Chapman, L. J. (2025a). Blackchin shiner exposed to warming and predation risk exhibit changes in behavioural and physiological metrics of thermal tolerance. Journal of Thermal Biology, 134, 104348. [DOI] [PubMed] [Google Scholar]
  37. Groves, V. , Brabant, C. , Boys, M. , & Chapman, L. J. (2025b). Non‐lethally produced chemical risk cues elicit antipredator responses in a common Canadian minnow. Ethology, 151, e13553. [Google Scholar]
  38. Groves, V. , Francispillai, E. K. , Reemeyer, J. E. , & Chapman, L. J. (2025c). Chemical risk cues impact fish behavior and thermal tolerance, but effects vary with predation experience. Current Zoology, 72, 166–181. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Haines, J. A. , Nason, S. E. , Skurdal, A. M. M. , Bourchier, T. , Boutin, S. , Taylor, R. W. , McAdam, A. G. , Lane, J. E. , Kelley, A. D. , Humphries, M. M. , Gorrell, J. C. , Dantzer, B. , Coltman, D. W. , & Haimalainen, A. (2020). Sex‐ and context‐specific associations between personality and a measure of fitness but no link with life history traits. Animal Behaviour, 167, 23–39. [Google Scholar]
  40. Hawlena, D. , & Schmitz, O. J. (2010). Physiological stress as a fundamental mechanism linking predation to ecosystem functioning. The American Naturalist, 176, 537–556. [DOI] [PubMed] [Google Scholar]
  41. Hothorn, T. , Bretz, F. , & Westfall, P. (2008). Simultaneous inference in general parametric models. Biometrical Journal, 50(3), 346–363. Portico. 10.1002/bimj.200810425 [DOI] [PubMed] [Google Scholar]
  42. Ingley, S. J. , Rehm, J. , & Johnson, J. B. (2014). Size doesn't matter, sex does: A test for boldness in sister species of Brachyrhaphis fishes. Ecology and Evolution, 4, 4361–4369. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Jackson, D. A. (2002). Ecological effects of Micropterus introductions: The dark side of black bass. In Black bass: Ecology, conservation, and management (pp. 221–232). Amer Fisheries Soc. [Google Scholar]
  44. Janssens, L. , Van Dievel, M. , & Stoks, R. (2015). Warming reinforces nonconsumptive predator effects on prey growth, physiology, and body stoichiometry. Ecology, 96, 3270–3280. [DOI] [PubMed] [Google Scholar]
  45. Kasumyan, A. O. (2022). Fish as sources of kairomones–chemical signals for aquatic animals. Journal of Ichthyology, 62, 289–315. [Google Scholar]
  46. Katzenberger, M. , Hammond, J. , Duarte, H. , Tejedo, M. , Calabuig, C. , & Relyea, R. A. (2014). Swimming with predators and pesticides: How environmental stressors affect the thermal physiology of tadpoles. PLoS One, 9, e98265. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Killen, S. S. , Cortese, D. , Cotgrove, L. , Chrétien, E. , Christensen, E. , Crespel, A. , Jolles, J. , Pineda, M. , Tiddy, I. C. , Fu, C. , Kochhann, D. , McKenzie, D. J. , & Munson, A. (2026). Further integrating social context into comparative and environmental physiology. Journal of Experimental Biology, 229, jeb251374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Kim, D. , Taylor, A. T. , & Near, T. J. (2022). Phylogenomics and species delimitation of the economically important black basses (Micropterus). Scientific Reports, 12, 9113. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Kimbell, H. S. , & Morrell, L. J. (2015). Turbidity influences individual and group level responses to predation in guppies, Poecilia reticulata . Animal Behaviour, 103, 179–185. [Google Scholar]
  50. Kordas, R. L. , Harley, C. D. G. , & O'Connor, M. I. (2011). Community ecology in a warming world: The influence of temperature on interspecific interactions in marine systems. Journal of Experimental Marine Biology and Ecology, 400, 218–226. [Google Scholar]
  51. Kuznetsova, A. , Brockhoff, P. B. , & Christensen, R. H. B. (2017). lmerTest package: Tests in linear mixed effects models. Journal of Statistical Software, 82(13). 10.18637/jss.v082.i13 [DOI] [Google Scholar]
  52. Lenth, R. V. (2024). Emmeans: Estimated marginal means, aka least‐squares means.
  53. Lima, S. L. , & Bednekoff, P. A. (1999). Temporal variation in danger drives antipredator behavior: The predation risk allocation hypothesis. The American Naturalist, 153, 649–659. [DOI] [PubMed] [Google Scholar]
  54. Maun, E. M. A. , & Schincariol, R. A. (2010). Impacts of water diversition on bioitc communities of a river in a dune watershed. National Research Council of Canada Monograph Publishing Program. [Google Scholar]
  55. McDonnell, L. H. , & Chapman, L. J. (2015). At the edge of the thermal window: Effects of elevated temperature on the resting metabolism, hypoxia tolerance and upper critical thermal limit of a widespread African cichlid. Conservation Physiology, 3, cov050. [DOI] [PMC free article] [PubMed] [Google Scholar]
  56. Mitchell, M. D. , Bairos‐Novak, K. R. , & Ferrari, M. C. O. (2017). Mechanisms underlying the control of responses to predator odours in aquatic prey. Journal of Experimental Biology, 220, 1937–1946. [DOI] [PubMed] [Google Scholar]
  57. Moffat, K. T. , Groves, V. , & Chapman, L. J. (2025). Impacts of elevated water temperature on the behaviour and thermal tolerance of the bluntnose minnow (Pimephales notatus). Canadian Journal of Zoology, 103, 1–8. [Google Scholar]
  58. Nyboer, E. A. , & Chapman, L. J. (2018). Cardiac plasticity influences aerobic performance and thermal tolerance in a tropical, freshwater fish at elevated temperatures. Journal of Experimental Biology, 221, jeb.178087. [DOI] [PubMed] [Google Scholar]
  59. Pilger, T. J. , Franssen, N. R. , & Gido, K. B. (2008). Consumption of native and nonnative fishes by introduced largemouth bass (Micropterus salmoides) in the San Juan River, New Mexico. The Southwestern Naturalist, 53, 105–108. [Google Scholar]
  60. Pintanel, P. , Tejedo, M. , Salinas‐Ivanenko, S. , Jervis, P. , & Merino‐Viteri, A. (2021). Predators like it hot: Thermal mismatch in a predator–prey system across an elevational tropical gradient. Journal of Animal Ecology, 90, 1985–1995. [DOI] [PubMed] [Google Scholar]
  61. Potts, L. B. , Mandrak, N. E. , & Chapman, L. J. (2021a). Coping with climate change: Phenotypic plasticity in an imperilled freshwater fish in response to elevated water temperature. Aquatic Conservation‐Marine and Freshwater Ecosystems, 31, 2726–2736. [Google Scholar]
  62. Potts, L. B. , Mandrak, N. E. , & Chapman, L. J. (2021b). Fine‐scale distribution and occupancy modelling of the threatened Pugnose shiner (Notropis anogenus) in the St. Lawrence River, Ontario, Canada. Canadian Journal of Fisheries and Aquatic Sciences, 78, 1293–1304. [Google Scholar]
  63. Pouca, C. V. , Mitchell, D. J. , Lefevre, J. , Vega‐Trejo, R. , & Kotrschal, A. (2021). Early predation risk shapes adult learning and cognitive flexibility. Oikos, 130, 1477–1486. [Google Scholar]
  64. R Core Team . (2024). R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing. https://www.R-project.org/ [Google Scholar]
  65. Raby, G. D. , Morgan, R. , Andreassen, A. H. , Stewart, E. M. C. , De Bonville, J. , Hoots, E. C. , Kuchenmüller, L. , Metz, M. , Rowsey, L. E. , Green, L. , Griffin, R. A. , Martin, S. , Reid, H. B. , Ern, R. , Åsheim, E. R. , Cowan, Z.‐L. , Leeuwis, R. H. J. , Blewett, T. A. , Speers‐Roesch, B. , … Jutfelt, F. (2025). Measuring critical thermal maximum in aquatic ectotherms: A practical guide. Methods in Ecology and Evolution, 16, 2208–2228. [Google Scholar]
  66. Reemeyer, J. E. , Rumball, D. , Mandrak, N. E. , & Chapman, L. J. (2024). Seasonal variation in thermal tolerance and hypoxia tolerance of a threatened minnow and a non‐imperilled congener: A cautionary tale for surrogate species in conservation. Conservation Physiology, 12, coae071. [DOI] [PMC free article] [PubMed] [Google Scholar]
  67. Reinhardt, U. G. , & Healey, M. C. (1997). Size‐dependent foraging behaviour and use of cover in juvenile coho salmon under predation risk. Canadian Journal of Zoology, 75, 1642–1651. [Google Scholar]
  68. Rilov, G. , Figueira, W. , Lyman, S. , & Crowder, L. (2007). Complex habitats may not always benefit prey: Linking visual field with reef fish behavior and distribution. Marine Ecology Progress Series, 329, 225–238. [Google Scholar]
  69. Sandblom, E. , Clark, T. D. , Gräns, A. , Ekström, A. , Brijs, J. , Sundström, L. F. , Odelström, A. , Adill, A. , Aho, T. , & Jutfelt, F. (2016). Physiological constraints to climate warming in fish follow principles of plastic floors and concrete ceilings. Nature Communications, 7, 11447. [DOI] [PMC free article] [PubMed] [Google Scholar]
  70. Schlosser, I. J. (1987). The role of predation in age‐ and size‐related habitat use by stream fishes. Ecology, 68, 651–659. [Google Scholar]
  71. Schmidt, K. A. , Dall, S. R. X. , & van Gils, J. A. (2010). The ecology of information: An overview on the ecological significance of making informed decisions. Oikos, 119, 304–316. [Google Scholar]
  72. Schmitz, O. J. , & Trussell, G. C. (2016). Multiple stressors, state‐dependence and predation risk — Foraging trade‐offs: Toward a modern concept of trait‐mediated indirect effects in communities and ecosystems. Current Opinion in Behavioral Sciences, 12, 6–11. [Google Scholar]
  73. Staton, S. K. , Vlasman, K. L. , & Edwards, A. L. (2009). Recovery strategy for the Lake Chubsucker (Erimyzon sucetta) in Canada, 2009.
  74. Strand, M. C. , DeVriendt, I. G. , Seigel, A. R. , Merkord, C. L. , & Wisenden, B. D. (2022). Hypoxia constrains behavioral responses to chemical alarm cues by fathead minnows Pimephales promelas . Environmental Biology of Fishes, 105, 1509–1517. [Google Scholar]
  75. Vavrek, M. A. , & Brown, G. E. (2009). Threat‐sensitive responses to disturbance cues in juvenile convict cichlids and rainbow trout. Annales Zoologici Fennici, 46, 171–180. [Google Scholar]
  76. Wickham, H. , Averick, M. , Bryan, J. , Chang, W. , McGowan, L. , François, R. , Grolemund, G. , Hayes, A. , Henry, L. , Hester, J. , Kuhn, M. , Pedersen, T. , Miller, E. , Bache, S. , Müller, K. , Ooms, J. , Robinson, D. , Seidel, D. , Spinu, V. , et al. (2019). Welcome to the Tidyverse. Journal of Open Source Software, 4(43), 1686. 10.21105/joss.01686 [DOI] [Google Scholar]
  77. Wisenden, B. D. (2015). Chemical cues that indicate risk of predation. In Sorensen P. W. & Wisenden B. D. (Eds.), Fish pheromones and related cues (pp. 131–148). Wiley. [Google Scholar]
  78. Zanette, L. Y. , & Clinchy, M. (2019). Ecology of fear. Current Biology, 29, R309–R313. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Figure S1 Environmental temperature taken before each thermal tolerance trial across the testing dates. Raw data are underlaid and the grey shading shows 95% confidence intervals.

Table S1: Modified table from Raby et al. (2025) with details for the thermal tolerance trials.

Table S2: Comparisons between stimuli for blackchin shiner critical thermal maximum (CTMax) via Tukey honest significant differences. Significant values (p < 0.05) are shown in bold.

JFB-109-1786-s001.docx (135.8KB, docx)

Data Availability Statement

Data and code will be available at the following upon publication: 10.6084/m9.figshare.32030136.

Articles from Journal of Fish Biology are provided here courtesy of Wiley

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