The role of temperature in the prey capture probability of drift‐feeding juvenile brown trout (Salmo trutta)

Abstract

Cold water temperatures are widely supposed to reduce the food intake of stream salmonids. Although cold temperatures have been documented to reduce swimming ability, digestion and gastric evacuation rates, little is known about how temperature influences the ability of fish to capture prey. We examined the effects of water temperature on the prey capture probability of drift-feeding juvenile brown trout (Salmo trutta) in a laboratory stream. Temperatures ranged between 5.7°C and 14°C. We found significant effects of water temperature on prey capture probability and capture manoeuvre time. The mean capture probability dropped from 96% at 14°C to 53% at 5.7°C. At 8°C and higher temperatures, foraging performances did not differ much among treatments. We suggest that reduced swimming ability could be one of the most important mechanisms for the observed pattern of reduced prey capture probability at cold water temperatures, but prey detection limitations and predator avoidance may play a role. Our results will be of use for bioenergetics-based drift-foraging models, which to date have not incorporated a temperature-dependent prey capture function.

Density‐dependent diel activity in stream‐dwelling Arctic charr Salvelinus alpinus

“…The model-averaged approach confirmed that fish are more active at high population density, but also showed that other ecological variables play key roles in shaping activity patterns. First, activity increased with water temperature, likely due to increased metabolic demands (Beamish 1964) as well as increased prey capture (Watz and Piccolo 2011) and position-holding (Graham et al 1996) abilities. In this study, metabolic demands were likely low because of low water temperatures, resulting in lower activity rates (mean = 13.2%) than have been observed in juvenile salmonids in warmer streams (e.g., mean = 36.8% in Breau et al 2007;23% in Roy et al 2013).…”

Effects of temperature and feeding frequency on ingestion and growth for rare minnow

“…Typically, food consumption and growth rate increase with increasing temperature up to a peak, but then decrease, with extreme temperatures leading to stress [19][20][21]. Temperature also affects hunger or appetite, which would in turn determine active foraging frequency [22]. Although increasing feeding frequency can improve growth, feeding at intervals shorter than the time required for regaining appetite is inefficient, and could even lead to gastric overload and reduction of absorption efficiency [23][24][25][26].…”

Temperature‐dependent prey capture efficiency and foraging modes of brown trout Salmo trutta

“…This study showed a positive relationship between the proportion of time a fish spent holding a foraging station and the fish's capture success when feeding on drifting prey, and the slope of this relationship was temperature‐dependent. At temperatures > 10·0° C, fish shared nearly equal capture success regardless of foraging mode, and all fish were able to capture most of the prey encountered (Watz & Piccolo, 2011; this study). Consequently, station holding did not correlate with drift capture success at these temperatures, similar to the findings of Grant & Noakes (1987) for stream‐dwelling young‐of‐the‐year brook trout Salvelinus fontinalis (Mitchill 1814) in summer.…”

“…It is plausible that the effect of environmental factors on prey capture success will differ for fish using different foraging modes. Water temperature, for example, has been reported to influence prey capture success (Hill & Grossman, 1993; Magoulick & Wilzbach, 1998; Watz & Piccolo, 2011), but it has not yet been explored how temperature affects the prey capture success of fish using different foraging modes. Using S. trutta as a test species, this study presents a test of the hypothesis that temperature influences the relationship between the proportion of time fish spend holding a fixed feeding station and their associated prey capture success.…”