Maintaining biodiversity is crucial for maximising ecosystem resilience. Despite this, anthropogenic disturbances are driving global biodiversity declines that are heightened in vulnerable ecosystems like coral reefs.
Coral reefs are impacted by sedimentation, overfishing and habitat degradation, which impacts biodiversity and therefore the range of functional roles of the reef fish that they support.
To evaluate how anthropogenic disturbances influence the functional richness of fish and the distribution of key functional groups, we surveyed coral reef fish assemblages across 135 sites in Beqa Lagoon, Fiji, using remote underwater video systems.
We found species richness and total abundance were typically greatest when coral extent within a 500-m buffer around a site was approximately 40,000 m2 and when a site was 20 km from the river mouth.
Corallivore, piscivore and zooplanktivore abundance were positively correlated with fish functional richness.
Sites greater than 20 km from a major river had greater functional richness, while corallivore abundance was highest farther from villages.
Piscivore abundance was highest at sites with moderate coral reef extent and zooplanktivore abundance was highest at sites that were at a moderate distance from the river.
Given these patterns, anthropogenic disturbance is one of the key drivers of functional richness decline on coral reefs.
Managing coral reef resilience within the region should therefore focus on reducing sediment and nutrient runoff and implementing fishing regulations that maintain ecological stability and resilience.
More thoroughly accounting for change in functional diversity when monitoring impacts and considering conservation strategies can help to safeguard coral reefs.
Keywords
Piscivore · Sedimentation · Subsistence fishing · Diversity · Coral reef, fish
Anthropogenic disturbance contributes to the loss of key fish functional groups and modifies functional richness on fringing reefs in Fiji
Christopher J. Henderson, Jesse D. Mosman, Helen Sykes, Anish Maharaj, Susan Nuske, Ken Kassem, Kelera Macedru, Andrew D. Olds, Ben L. Gilby, Lucy A. Goodridge Gaines, Ashley J. Rummell & Paul S. Maxwell
July 2026
Coral Reefs
https://doi.org/10.1007/s00338-026-02927-7
- Brief Report
- Open access
- Published: 13 July 2026
- (2026)
- Cite this article
Acknowledgements
We thank and acknowledge all the communities within the Navua catchment and lagoon who supported the development of this work.
The Government of Fiji supported the development of this broader project through input and review from several government agencies including the three provincial governments and various line ministries.
The work was led in partnership with the Fiji Ministry of Environment and Climate Change and the Secretariat of the Pacific Regional Environment Programme (SPREP) through the By-catch and Integrated Ecosystem Management (BIEM) Initiative of the Pacific-European Union Marine Partnership (PEUMP) Programme funded by the European Union and the Government of Sweden.
This manuscript has been prepared with the financial support of the Pacific-European Union Marine Partnership (PEUMP) Programme, funded by the European Union and the Government of Sweden.
Its contents do not necessarily reflect the views of the European Union or the Government of Sweden.
This manuscript has been compiled in good faith, exercising all due care and attention.
SPREP does not accept responsibility for inaccurate or incomplete information.
