A team of international and North Queensland researchers from James Cook University discovered that the relationship between fish and corals could not be as strong as experts had previously thought. The study was published in Nature Ecology & Evolution.
Coral use among fishes and the correlation coefficients (r) between fish metrics (abundance, biomass and species richness) and the percentage of coral cover. a, Coral-associated damselfish (Dascyllus aruanus) shelter within branching hard coral. b, An obligate coral-feeding butterflyfish (Chaetodon meyeri) preying on coral polyps. c, Location for each correlation coefficient (r) (n = 723), mapped using an Eckert IV projection. Panels a and b reproduced with permission from François Libert. Image Credit: Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02334-7
The lead author, Pooventhran Muruga, a JCU Ph.D. candidate, reviewed over 4,600 studies on the interaction between fish and corals.
Undeniably, coral reefs serve as a key habitat for reef fishes, providing both shelter and food. It is therefore no surprise that for more than four decades there has been a widespread consensus that reef fishes are associated with reef-building corals.
Pooventhran Muruga, Study Lead Author and PhD Candidate, James Cook University
Muruga added, “But on closer inspection of the literature, we found a large variability within and across fishes and locations and globally there were only weak associations between fishes and corals.”
Professor David Bellwood, the study’s co-author, stated that the findings called into question beliefs about the intensity and prevalence of fish-coral relationships.
I would caution against assuming a direct and omnipresent relationship between the two.
David Bellwood, Study Co-Author and Professor, James Cook University
Co-author Dr. Alexandre Siqueira stated that the apparent inadequacy of fish-coral relationships, along with the survival of some fish populations in the face of catastrophic coral loss, highlighted the need to recognize that coral cover alone may not have as powerful an impact on fishes as previously assumed.
Muruga suggested that rather than a vital dependency, fish and corals may be two coexisting creatures in a far more complicated ecosystem.
Muruga added, “The findings don’t downplay the importance of corals on reef but suggest there is more to the relationship. It emphasizes the need to look beyond the simple paradigm of more coral equals more fish and acknowledge the complex processes that structure and maintain coral reef communities.”
Journal Reference:
Muruga, P., et. al. (2024). Meta-analysis reveals weak associations between reef fishes and corals. Nature Ecology & Evolution. doi:10.1038/s41559-024-02334-7.