Julia Rodriguez Fillol Masters Student

University of Exeter


Exploring parrotfish feeding in the context of nutrient enrichment from seabird guano deposits

The unique feeding mechanism of parrotfishes plays crucial ecological roles in tropical coral reefs. By scraping and excavating the substrate, parrotfishes disturb benthic communities, remove calcareous layers of the reef and contribute to the formation, reworking and transport of sediments. Although previously  considered generalist herbivores, new evidence regards parrotfishes as “microphages” which target epilithic and endolithic microorganisms colonising the substrate. These organisms, predominantly cyanobacteria, provide a protein-rich nutritional source and, therefore, represent a principal dietary target for some parrotfish species. 


My Masters by Research will explore the intricacies of parrotfish feeding in the context of nutrient enrichment from seabird guano deposits. I aim to study parrotfish feeding rates, dietary targets and substrate preferences across nutrient gradients in the Seychelles.  The project will involve observations of parrotfish feeding and microhistology analyses of core samples from reef substrata. 

Seabird-derived nutrients from breeding colonies leach to surrounding reefs and mediate patterns in primary production. An enhanced availability of photoautotrophs, particularly microbes, may have implications for parrotfish feeding, and consequently, the ecological functions performed by this diverse and abundant group of fish.

The introduction of invasive species to island ecosystems poses an major threat to biodiversity. For example, the loss of breeding seabird colonies as a result of rat infestations has cascading effects which alter productivity and functioning on nearby coral reefs. Invasive species eradication, ecological restoration and reinvasion prevention remain challenging, however, should be considered a conservation priority.

Julia Rodriguez Fillol


2022 Present
MbyRes student at the University of Exeter
2022 2022
Operation Wallacea Galapagos naturalist in San Cristobal island
2021 2021
Marine conservation intern in Curieuse island, Seychelles
2020 2021
MSc Marine Biology at Bangor University
2018 2018
Marine and terrestrial conservation volunteer in Curieuse Island, Seychelles

My Project

  • Island Reef Connections
    Implications of Nutrient Flow and Feedback Across the Seabird-Island-Reef System

Other Interests

I am interested in the effects of natural and anthropogenic nutrient inputs on coral reef community structure and function. Although nutrient enrichment arising from human activity is consider detrimental to corals, natural nutrient subsidies, such as seabird guano or upwelling, can promote coral growth and support reef health. Understanding the mechanisms driving community responses to nutrient enrichment can help predict future scenarios and develop conservation strategies.