Prey or predator: 0+ perch (Perca fluviatilis) in the trade-off between food and shelter

Abstract

The 0+ cohort of perch can split into a slow-growing planktivorous and a fast-growing piscivorous cohort during their first months of life. Both cohorts are, however, vulnerable to predation by piscivorous fish. Laboratory experiments were performed to test the behavior of 0+ perch as a predator of cyprinids, and in the tradeoff between food and shelter from the threat of predators. In the foraging trials, 0+ perch attacked bream faster than they did carp, and vegetation hampered the aggression against bream. In the second experiment, the habitat selection of two size classes of 0+ perch under the threat of predation was monitored. Overall, vegetation structures were preferred by both size classes of 0+ perch. When small fish were offered to the 0+ perch as food, the open water becomes more attractive. The results of the habitat use trials further show that the two size cohorts of 0+ perch may also differ in their behavior, in that the availability of fish as food becomes more important than the shelter of vegetation structures for the larger perch.

Context‐dependent reproductive habitat selection: the interactive roles of structural complexity and cannibalistic conspecifics

“…2008), and numerous species have been shown to prefer foraging effectively in structurally simple patches, but escape to safer complex patches when faced with a predator (e.g. Persson & Eklov 1995; Stoks 1999; Borcherding 2006), or predator cues (e.g. Rypstra et al.…”

Food abundance affects both morphology and behaviour of juvenile perch

“…Also, after 48 h of food restriction, hungry juvenile Atlantic salmon spent less time in refuge under the threat of predation compared with individuals fed to excess (Vehanen 2003). Thus, the level of nourishment is an important factor that may alter boldness in the trade‐off between foraging and predation risk, and it is a potential factor that may quickly hide other proximate cues like environment (Magnhagen 2006), type of food (Borcherding 2006; M. Heynen and J. Borcherding, unpublished data), individual learning (Kelley & Magurran 2003a; Kelley et al. 2003) social constraints (Magnhagen & Staffan 2005) or different sizes within an age class (Brown & Braithwaite 2004; Borcherding 2006).…”

Development of abundance and size structure of young-of-the-year perch populations using three methods

“…These results for the gravel pit lakes give clear evidence that size-specific occurrence of the perch caused the observed size differences between electrofishing and gillnet catches. The reason for this differential occurrence in the different habitats may be related to size-specific patterns of foraging, competition or predation (Eklöv and Diehl, 1994;Beeck et al, 2002;Olsson and Eklöv, 2005;Borcherding, 2006;Eklöv and Svanbäck, 2006;Koenig et al, 2006;Borcherding et al, 2007;Olsson et al, 2007;Magnhagen and Borcherding, 2008). In lakes with more shallow but unstructured littoral zones, beach seining is also a very effective method for estimating densities of fish up to sizes of about 100 mm TL (e.g., Staas, 1996;Jurajda et al, 1997).…”

“…In contrast to the gillnet samples, PAS is relatively independent of the swimming performance of the fish (not to be confused with the escape ability) and consequently this method is also suitable for resting or slow-swimming fish that are not trapped by gillnets. We know (1) from stomach analyses that large-sized YOY perch prey on their small-sized siblings in the ponds (Urbatzka et al, 2008, Heermann and Borcherding, unpublished results), and that (2) small-sized YOY perch are more timid than their larger siblings when foraging for food under the risk of predation (Borcherding, 2006;Koenig et al, 2006). Consequently, we assume reduced swimming activity of the small-sized perch in the experimental ponds due to high predation pressure by their cannibalistic siblings, for which no risk from predatory fish exists.…”