Dispersal without errors: symmetrical ears tune into the right frequency for survival

Area of Science:

• Ichthyology
• Sensory Ecology
• Developmental Biology

Background:

• Vertebrates use binaural acoustic cues for sound localization, necessitating symmetrical auditory structures.
• Sound is a critical cue for reef fish larvae navigating to settlement habitats.
• The integrity of the auditory organ, specifically otolith symmetry, is crucial for larval hearing and navigation.

Purpose of the Study:

• To investigate the relationship between otolith symmetry and the navigational success of reef fish larvae.
• To determine if otolith asymmetry affects the detection of suitable reef habitats and larval recruitment.
• To examine if embryonic otolith asymmetries are corrected during larval development.

Main Methods:

• Quantified otolith symmetry in fish larvae.
• Assessed the ability of larvae to detect and recruit to settlement habitats.
• Examined otolith development and potential compensatory growth during the larval stage.

Main Results:

• Larvae with asymmetrical otoliths exhibited significant difficulties in detecting suitable settlement habitats.
• Otolith asymmetry was associated with increased mortality rates in fish larvae.
• Embryonic otolith asymmetries were not compensated by later growth during the larval period.

Conclusions:

• Otolith asymmetry negatively impacts reef fish larvae's ability to locate and recruit to reefs.
• Persistent otolith asymmetries contribute to higher larval mortality, influencing population dynamics.
• Auditory organ symmetry is a significant factor shaped by natural selection in wild fish populations.