The effect of ocean acidification on otolith morphology in larvae of a tropical, epipelagic fish species, yellowfin tuna ( Thunnus albacares )

• Published in: Journal of Experimental Marine Biology and Ecology
• Main Authors: Wexler, Jeanne B., Margulies, Daniel, Scholey, Vernon, Lennert-Cody, Cleridy E., Bromhead, Don, Nicol, Simon, Hoyle, Simon D., Stein, Maria, Williamson, Jane E., Havenhand, Jon
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Ocean acidification; Otolith fluctuating asymmetry; Otolith growth; Somatic growth; Yellowfin tuna larvae; Pacific
• Online Access: https://researchers.mq.edu.au/en/publications/cece6391-1057-4964-851c-28141e8eca4c; https://doi.org/10.1016/j.jembe.2023.151949; http://www.scopus.com/inward/record.url?scp=85171737666&partnerID=8YFLogxK

Increasing ocean acidification is a concern due to its potential effects on the growth, development, and survival of early life stages of tuna in oceanic habitats and on the spatial extent of their suitable nursery habitat. To investigate the potential effects of increasing CO 2 on otolith calcification of 9-day old pre-flexion stage yellowfin tuna ( Thunnus albacares ), an experiment was conducted at the Inter-American Tropical Tuna Commission's Achotines Laboratory in Panama during 2011. Fertilized eggs and larvae were exposed to mean p CO 2 levels that ranged from present day (355 μatm) to two levels predicted to occur in some areas of the Pacific in the near future (2013 and 3321 μatm), and to an extreme value equivalent to long-term projections for 300 years in the future (9624 μatm). The results indicated significantly larger otoliths (in area and perimeter) with significant, and increasing, fluctuating asymmetry at acidification levels similar to those projected for the near future and long-term. Otoliths increased significantly in size despite a significant decrease in somatic length with increasing p CO 2 . A consistent correlation between otolith and somatic growth of yellowfin tuna larvae among treatments was evident (i.e., larger otoliths were still associated with larger larvae within a treatment). The observed changes in otolith morphology with increasing ocean acidification have the potential to indirectly affect larval survival through dysfunction of the mechanosensory organs, but this remains to be verified in yellowfin tuna larvae.