Supplementary material - Details on study area, species, methods and additional results from Ocean acidification affects somatic and otolith growth relationship in fish: evidence from an in situ study.

• Main Authors: Antonio Di Franco, Antonio Calò, Khalil Sdiri, Carlo Cattano, Marco Milazzo, Paolo Guidetti
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2019
• Subjects: Environmental Science; Ecology; CO2 seeps; coastal fish; ocean acidification; otoliths; pCO2 variability; somatic growth; Ocean acidification
• Online Access: https://doi.org/10.6084/m9.figshare.7701110.v2; https://figshare.com/articles/journal_contribution/Supplementary_material_-_Details_on_study_area_species_methods_and_additional_results_from_Ocean_acidification_affects_somatic_and_otolith_growth_relationship_in_fish_evidence_from_an_i_in_situ_i_study/7701110

Ocean acidification (OA) may have varied effects on fish eco-physiological responses. Most OA studies have been carried out in laboratory conditions without considering the in situ p CO 2 /pH variability documented for many marine coastal ecosystems. Using a standard otolith ageing technique, we assessed how in situ ocean acidification (ambient, versus end-of-century CO 2 levels) can affect somatic and otolith growth, and their relationship in a coastal fish. Somatic and otolith growth rates of juveniles of the ocellated wrasse Symphodus ocellatus living off a Mediterranean CO 2 seep increased at the high- p CO 2 site. Also, we detected that slower-growing individuals living at ambient p CO 2 levels tend to have larger otoliths at the same somatic length (i.e. higher relative size of otoliths to fish body length) than faster-growing conspecifics living under high p CO 2 conditions, with this being attributable to the so-called ‘growth effect’. Our findings suggest the possibility of contrasting OA effects on fish fitness, with higher somatic growth rate and possibly higher survival associated with smaller relative size of otoliths that could impair fish auditory and vestibular sensitivity.