The behavioral response of prey fish to predators: the role of predator size

Abstract

Predation is one of the key factors governing patterns in natural systems, and adjustments of prey behaviors in response to a predator stimulus can have important ecological implications for wild fish. To investigate the effects of predators on the behavior of prey fish and to test whether the possible effects varied with predator size, black carp (Mylopharyngodon piceus) and snakehead (Channa argus) (a size-matched predator treatment with a similar body size to prey fish and a larger predator treatment with approximately 2.7 times of the body mass of prey fish) were selected to function as prey and predator, respectively. Their spontaneous activities were videorecorded in a central circular arena surrounded by a ring holding the stimulus fish. The distance between prey and predator fish was approximately 200% of the distance between two prey fish, which suggested that black carp can distinguish their conspecifics from heterospecifics and probably recognize the snakehead as a potential predator. The prey fish spent substantially less time moving and exhibited an overall shorter total distance of movement after the size-matched or large predator was introduced, which possibly occurred due to increased vigilance or efforts to reduce the possibility of detection by potential predators. However, there was no significant difference in either distance or spontaneous activities between two predator treatments. These findings suggested that (1) an anti-predator strategy in black carp might involve maintaining a safe distance, decreasing activity and possibly increased vigilance and that (2) the behaviors of prey response to predators were not influenced by their relative size difference.

Captive-born collared peccary (Pecari tajacu, Tayassuidae) fails to discriminate between predator and non-predator models

“…Prey species can use some characteristics of their predators to evaluate predation risk: body size, eye position and eye-gaze, olfactory cues and sounds cues (Carter et al 2008;Hettena et al 2014, Schmitz 2017Tang et al 2017). For example, the larger the predator, the greater the risk of predation (Cohen et al 1993;Preisser & Orrock 2012).…”

No experimental evidence of stress-induced hyperthermia in zebrafish (Danio rerio)

“…While our study is limited to laboratory studies, from an ecological perspective, evidence of SIH in fish may raise questions. Many studies have shown that a common behavioural response to the presence of predators in fish is reduced swimming activity and/or lowered metabolism (Kopack et al, 2015;Tang et al, 2017). Moving to warmer areas in response to a stressor, as is required to exhibit SIH, would be at odds with this anti-predator response in many fish.…”

Behavioral adjustments to prior predation experience and food deprivation of a common cyprinid fish species vary between singletons and a group

“…The trajectory of each frame was digitized with the idTracker software (Pérez-Escudero et al, 2014; Tang et al, 2017), which automatically tracked the position of each fish in each trial and provided all x and y coordinates for each fish in each video (Miller & Gerlai, 2012; Killen et al, 2016). When the fish were measured in the group, only the data from the focus fish were recorded and analyzed.…”