The effect of turbidity and prey fish density on consumption rates of piscivorous Eurasian perch Perca fluviatilis

Abstract

Predator ]. Perch consumption rates were affected by visibility less than expected, while they were highly affected by increased prey fish density. Perch responded to high prey density in all visibility conditions, indicating that prey density is more crucial for consumption than visibility in turbid lakes.

Influence of limnological zones on the spatial distribution of fish assemblages in three Brazilian reservoirs

“…However, they were more abundant at riverine sites, where the total fish abundance was also higher. In Três Marias, increased prey density at riverine zone may have compensated the visual foraging constraints for the distribution of non-native predators, as observed by Jacobsen et al (2014). According to this researcher, although predators be successful in high-visibility environments, predation rates may also be higher in places with lower visibility, but with high abundance of prey.…”

Fine‐scale movement ecology of a freshwater top predator, Eurasian perch (Perca fluviatilis), in response to the abiotic environment over the course of a year

“…Through altering physiological processes and prey distributions (Brown et al, 2004;Hinch & Rand, 1998;Magnuson et al, 1979), temperature influences various behaviours, such as swimming intensity (Alabaster & Stott, 1978;Neuman et al, 1996), foraging rates (Kitchell, Stewart, & Weininger, 1977;Neuman et al, 1996), escape ability of prey (Wilson, Lefrancois, Domenici, & Johnston, 2010) and timing of migration and spawning (McKinzie, Jarvis, & Lowe, 2014). The movement change in response to light is also likely to reflect foraging behaviour, considering that perch become more efficient at finding and consuming food as visibility increases (Jacobsen et al, 2014). It is also possible that the swimming activity increased in warmer water through higher activity of prey fish (Jacobsen, Berg, Jepsen, & Skov, 2004; and higher intraspecific competition for food (Ohlberger et al, 2012).…”

“…It is likely that perch increased the swimming activity at higher temperature to meet the elevated demand for food, considering that higher swimming activity increases prey encounter rates (Turesson & Brönmark, 2004. Considering that perch can hunt even at low light levels (Jacobsen et al, 2014), it is likely that perch continue to forage during the night-time in summer, possibly to maintain high foraging rates in the warm summer period. In addition, swimming activity was strongly elevated before and during the spawning period, suggesting that the swimming activity is related to finding spawning places and mates.…”

“…We also found that perch responded to stronger wind by reducing swimming distance and activity area and moving closer the shore. For example, strong wind can increase the efficiency of foraging littoral prey by causing water turbulence and distraction (Jacobsen et al, 2014). For example, strong wind can increase the efficiency of foraging littoral prey by causing water turbulence and distraction (Jacobsen et al, 2014).…”

Between- and within-individual variation in activity increases with water temperature in wild perch

“…In fish in particular, water temperature tightly regulates metabolism and, consequently, influences energetic demands (Clarke and Johnston 1999;Cossins and Bowler 1987). Water temperature can also act as a controlling factor of primary productivity (Keller 1989;Regaudie-de-Gioux and Duarte 2012), which influences the abundance of prey fish (Downing et al 1990) and, consequently, the activity of predator fish (Jacobsen et al 2014). Although activity of fish is influenced by many other environmental factors such as light (Cerri 1983;Diehl 1988) and seasonality (Jacobsen et al 2002;Hanson et al 2007), water temperature is thus a useful proxy for a broader ecological gradient, considering that many environmental factors are cross-correlated in the wild.…”