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Positive indirect effects of top‐predators on the behaviour and survival of juvenile fishes
Author(s) -
Palacios Maria del Mar,
McCormick Mark I.
Publication year - 2021
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1111/oik.07731
Subject(s) - mesopredator release hypothesis , predation , juvenile , biology , apex predator , intraguild predation , predator , trophic cascade , foraging , predatory fish , ecology , kleptoparasitism
Top‐predators can suppress mesopredator behaviour through risk effects. However, there is limited understanding of whether such behavioural suppression can dampen the lethal and sub‐lethal effects of mesopredators on bottom level prey. Here, we document a field experiment that examines whether the presence of top‐predator cues (visual and chemical stimuli from a coral trout) can cascade to indirectly influence the behaviour and survival of juvenile fish prey of different species ( Pomacentrus amboinensis and P. chrysurus ) and size (small = 1.18 cm SL versus large = 1.32 cm SL). Results showed that habitat patches exposed to top‐predator cues received fewer visits and foraging attacks from mesopredators, leading to higher space use (~ 46%), feeding rate (~ 95%) and survival (~ 67%) from juvenile fish prey. Survival was always higher for individuals of P. amboinensis and of large‐size, independent of the presence or absence of top‐predator cues. Our data indicate that predation risk from the top‐predator indirectly favoured the persistence and behaviour of juvenile fishes by promoting risk‐averse behavioural responses in mesopredators. This study underscores the behavioural mechanisms by which risk effects can cascade through the food web and highlights the consequences that harvesting top‐predators may have on the replenishment of bottom prey populations.