Clarifying the size–frequency relationship in clownfish acoustic signals

Body size is the principal determinant of acoustic variation in anemonefish, reflecting both the mechanics of sound production and the size-based structure of their social hierarchies. In Amphiprion percula, the absence of a reported size-frequency relationship has led to the interpretation that small acoustic differences are rank-specific. We show that this outcome stems from analytical choices that obscure natural size variation, including pooling individuals across groups and removing size–rank covariance. Because behavioural categories correspond to distinct size classes, morphology must be explicitly accounted for.