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The parrotfish–coral relationship: refuting the ubiquity of a prevailing paradigm


Russ, GR and Questel, S-LA and Rizzari, JR and Alcala, AC, The parrotfish-coral relationship: refuting the ubiquity of a prevailing paradigm, Marine Biology, 162, (10) pp. 2029-2045. ISSN 0025-3162 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 Springer-Verlag Berlin Heidelberg

DOI: doi:10.1007/s00227-015-2728-3


It has become almost paradigmatic in the coral reef literature that fishing-induced reductions of parrotfish abundance cause benthic phase shifts from coral to macroalgal dominance. This study examined the alternatives of top-down control of the benthos by parrotfish density and bottom-up control of parrotfish density by the benthos at four Philippine islands in a long-term (7.5–30 years) "natural experiment". No-take marine reserves (NTMRs) demonstrated that fishing reduced parrotfish density significantly at two islands (Sumilon, Mantigue), but not significantly at two other islands (Apo, Selinog). There was no evidence that cover of hard coral decreased, nor macroalgal cover increased, in fished areas relative to NTMRs, no evidence that parrotfish density affected hard coral cover significantly, and thus no evidence of top-down, fishing-induced benthic phase shifts at all four islands. There was, however, compelling evidence that benthos (cover of dead substrata and hard coral) exerted strong bottom-up control on parrotfish density. This bottom-up control was demonstrated most clearly by major environmental disturbances (e.g. typhoons, coral bleaching) that changed benthic habitat and, subsequently, parrotfish density. As hard coral cover declined (and cover of dead substratum increased), parrotfish density increased and vice versa. This response occurred in both major parrotfish feeding guilds (scrapers and excavators). This long-term study on heavily fished coral reefs suggests that the benthos drives the parrotfish, not the other way around. The paradigm of fishing-induced benthic phase shifts may not apply to all coral reefs at all times. Multiple drivers of benthic change on coral reefs should always be considered.

Item Details

Item Type:Refereed Article
Keywords:herbivory, no-take marine reserve, Philippines, benthic habitat, coral reefs
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Rizzari, JR (Dr Justin Rizzari)
ID Code:120324
Year Published:2015
Web of Science® Times Cited:107
Deposited By:Fisheries and Aquaculture
Deposited On:2017-08-22
Last Modified:2017-09-07

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