A presentation by Empro J. Howard Choat, College of Science & Engineering James Cook University

Showing 2 of 2 dates for this event.
Dates available from 12 Nov 2019 until 12 Nov 2019

Event date: 12Nov 2019

Tuesday 12 Nov 2019

ATSIP Seminar Room 030, Building 145

  • 12:00 pm

James Cook University, Townsville QLD

Event date: 12Nov 2019

Tuesday 12 Nov 2019

Cairns Institute Building D003-003 (Ground floor meeting room)

  • 12:00 pm

James Cook University, Cairns QLD

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Please join us for this Tropical Landscapes Joint Venture Seminar Series


The hypothesis that feeding by herbivorous reef fish plays a significant role in determining alga cover on coral reefs has been a primary paradigm of coral reef ecology for three decades.

Group of people standing on a lookout with the ocean and cliffs in the background..

The hypothesis predicts that reefs are in a state of dynamic balance, maintained by herbivorous fish. Reduction in herbivore abundance compromises their ability to remove the autotrophs that inhibit the recruitment and growth of scleractinian corals. Under these circumstances reefs may undergo a shift from domination of the benthic biota by corals to one dominated by turfing and macroscopic algae. A consequence of this is a predicted reduction in reef “health” and resilience including declining fish populations and inhibition of the flux of nutrients and energy through coral reef ecosystems. However testing the hypothesis has been compromised by a highly selective approach to the interaction between herbivorous fish and their dietary targets.

Recently more comprehensive approaches based on demography, feeding behaviour, functional anatomy and digestive processing have indicated a need to re-evaluate this hypothesis. An alternative hypothesis that predicts the abundance and feeding activity of herbivores is driven by disturbance-mediated changes in resource levels argues for a very different approach to the management of coral reef biotas. However, reversing three decades of ecological thinking and management approaches based on a top-down model of coral reef herbivory will not be a simple task.


JH Choat has been interested in the evolution, ecology and nutritional biology of herbivorous reef fish for over four decades; a study that has involved sampling and observational work over all the major tropical ocean basins of the world.

The main part of this work has been carried out in association with five colleagues; DR Robertson (Smithsonian Tropical Research Institute), KD Clements (University of Auckland), BM Taylor (AIMS WA), R Hamilton (TNC) and M Berumen (KAUST Saudi Arabia). Much of the focus has been on the estimation of demographic rates in reef fish populations through the analysis of otolith microstructure, digestive processes in marine herbivores, and abundance and diversity patterns of herbivorous fishes from local to biogeographic spatial scales.

The most recent work has focussed on the response of reef fishes to the impacts of disturbances on reef habitats and the evolutionary history of dominant reef herbivores, including scarine labrids (parrotfish) and kyphosids (drummers). The results of this work have been applied to the management and conservation of reef fish populations through IUCN and through non-government organisations such as TNC.


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