Reconstructing reef fish communities using fish otoliths in coral reef sediments

PLoS One. 2019 Jun 14;14(6):e0218413. doi: 10.1371/journal.pone.0218413. eCollection 2019.

Abstract

Little is known about long-term changes in coral reef fish communities. Here we present a new technique that leverages fish otoliths in reef sediments to reconstruct coral reef fish communities. We found over 5,400 otoliths in 169 modern and mid-Holocene bulk samples from Caribbean Panama and Dominican Republic mid-Holocene and modern reefs, demonstrating otoliths are abundant in reef sediments. With a specially-built reference collection, we were able to assign over 4,400 otoliths to one of 56 taxa (35 families) though mostly at genus and family level. Many otoliths were from juvenile fishes for which identification is challenging. Richness (by rarefaction) of otolith assemblages was slightly higher in modern than mid-Holocene reefs, but further analyses are required to elucidate the underlying causes. We compared the living fish communities, sampled using icthyocide, with the sediment otolith assemblages on four reefs finding the otolith assemblages faithfully capture the general composition of the living fish communities. Radiocarbon dating performed directly on the otoliths suggests that relatively little mixing of sediment layers particularly on actively accreting branching coral reefs. All otolith assemblages were strongly dominated by small, fast-turnover fish taxa and juvenile individuals, and our exploration on taxonomy, functional ecology and taphonomy lead us to the conclusion that intense predation is likely the most important process for otolith accumulation in reef sediments. We conclude that otolith assemblages in modern and fossil reef sediments can provide a powerful tool to explore ecological changes in reef fish communities over time and space.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Coral Reefs*
  • Dominican Republic
  • Fishes*
  • Fossils*
  • Geologic Sediments / chemistry*
  • Otolithic Membrane / chemistry*
  • Panama

Grants and funding

Funding was provided by the Secretaría Nacional de Ciencia y Tecnología e Innovación (SENACYT), the Sistema Nacional de Investigadores (SNI) de SENACYT, NSF (EAR13-25683), Smithsonian Institution, STRI to A. O’Dea and the Smithsonian Tropical Research Institute fellowship program to C.-H. Lin. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.