Poster Australian Marine Sciences Association 2022

Daily age validation of otolith increments in expatriated damselfish Abudefduf vaigiensis, a key to unlock climate-related growth performance. (#517)

Alexander Rigg 1 , Clara Bellotto 1 , Ashley Fowler 2 , David Booth 1
  1. Uts, Sydney, NSW, Australia
  2. New South Wales Department of Primary Industries, Sydney Institute of Marine Science, Chowder Bay, NSW, Australia

Climate change has induced a poleward range expansion of coral reef fishes. One such “vagrant” species, the damselfish Abudefduf vaigiensis, is used as a model to understand life history impacts and community dynamics of coral reef fishes in temperate receiving environments. Otolith (earstone) microstructures have been used to proxy growth performance, but this relies on each otolith increment (ring) representing a single day of growth. We evaluated the validity of daily ring deposition in all three otoliths (sagittae, lapilli, and astericii) by using fluorescent staining protocols. Juvenile A. vaigiensis were exposed to three different Alizarin Red S concentrations on Days 1 and 11. The Alizarin marking on the three otolith types were evaluated for quality and whether daily rings were deposited between stains (i.e., rings validation). While all otoliths’ daily rings were successfully validated, the lapilli and sagittae presented a higher clarity in deposition and fluorescent markings than the astericii. This investigation reveals the utility of both sagittae and lapilli otoliths of early life history analysis in vagrants. Fluorescent markings on the second stain resulted in a lower clarity and increment widths of rings abruptly narrowed after first staining, suggesting that stain may affect growth.