Alarm cue specificity and response ontogeny in juvenile rainbow trout (Oncorhynchus mykiss)

Abstract

Many aquatic prey animals release chemical cues upon being captured by a predator. These chemical cues, referred to as alarm cues, may act to warn nearby individuals of danger. For the cues to be useful, fish must be able to discern if they are indicative of a real threat; cues from conspecifics in different age groups may be irrelevant due to size- and habitat-related shifts in predation risk. We test the response of newly-hatched rainbow trout, Oncorhynchus mykiss, to three concentrations of alarm cues from conspecifics from two age groups: newly-hatched versus six-month-old juveniles. Newly-hatched trout demonstrated a significant fright response to all three concentrations of alarm cues, but showed no difference in strength of response based on either concentration or age of the cue donor. We propose that the newly-hatched trout did not respond differently because of the high risk of predation that they face during this life stage.

A death in the family: Sea lamprey (Petromyzon marinus) avoidance of confamilial alarm cues diminishes with phylogenetic distance

“…Larval sea lamprey are able to detect and respond to damage‐released alarm cues by exhibiting reduced drift rates in the presence of the cue, indicating the cue operates throughout ontogeny (Wagner, Kierczynski, Hume, & Luhring, ). Furthermore, there is no evidence of life‐stage‐specific alarm cues in sea lamprey as has been reported in juvenile damselfish (Lönnstedt & McCormick, ; Mitchell & McCormick, ; but see Horn & Chivers, ). Instead, larvae respond to the adult alarm cue (Wagner et al., ) and adults respond to the larval alarm cue (Bals & Wagner, ).…”