Balance dysfunction in large yellow croaker in response to ocean acidification

Area of Science:

• Marine Biology
• Ecotoxicology
• Fish Physiology

Background:

• Large yellow croaker (Larimichthys crocea) are commercially important, sound-sensitive fish.
• Ocean acidification poses a threat to marine species, particularly those reliant on auditory senses.

Purpose of the Study:

• To investigate the effects of ocean acidification on the inner ear system of large yellow croaker.
• To assess impacts on otolith morphology, balance, and molecular responses.

Main Methods:

• Exposure of fish to four CO2 treatments (440-3000 ppm) for 50 days.
• Analysis of otolith (sagitta, asteriscus, lapillus) perimeter and mass.
• RNA-sequencing (RNA-Seq) to identify differentially expressed genes (DEGs).

Main Results:

• Acidification altered sagittal otolith shape and surface texture.
• Higher CO2 levels (1800-3000 ppm) impaired fish balance and caused lapillus asymmetry.
• DEGs were enriched in nervous system and bone mineralization pathways at higher CO2 concentrations.

Conclusions:

• Ocean acidification adversely affects the auditory and balance functions of large yellow croaker.
• Molecular responses indicate stress on the nervous system and bone metabolism.
• These findings highlight potential threats to fish populations and fisheries management.