Predator presence affects activity patterns but not food consumption or growth of juvenile corkwing wrasse (Symphodus melops)

Indirect effects of predators can manifest themselves as changes in prey behaviour and physiology. Given that digestion requires energy, it has been suggested will choose to eat smaller meals under predation risk reserve a larger portion the aerobic metabolic scope they have available for energetically demanding tasks more critical than digestion, such escape. To test this prediction, we quantified food consumption growth juvenile corkwing wrasses (Symphodus melops) over 11 days presence or absence predator (Atlantic cod, Gadus morhua). We then same behavioural arenas with predator. All was examined context would during digestive period. Overall, there no effect exposure on growth, yet predator-exposed were consistent their daily consumption, lending some support our prediction bet-hedging meal size risk. The lack clear pattern may resulted from relatively low percentage (~ 20–27%) being occupied by fish retained ample capacity activities other digestion. In subsequent trials, active spent time near cod predator-naïve wrasses, suggesting former had habituated threat risk-taking. Our results highlight complex often counter-intuitive populations beyond direct consumption. Predators affect species simply present environment. Such intimidation change activity patterns be important ecosystem dynamics. However, compared changes, know little about how indirectly investigated if deliberately less when is present, order retain sufficient physiological avoiding potential attack, top costly process digesting. While study confirms encounters reduce activity, appeared rapidly habituate did not see reduced fish; these were, however, unexposed still mindful protecting