Impact of shark-feeding tourism on surrounding fish populations off Moorea Island (French Polynesia)
Matthias Vignon A B E , Pierre Sasal A B , Ryan L. Johnson C D and René Galzin A BA UMR 5244 CNRS EPHE UPVD, Biologie et Écologie Tropicale et Méditerranéenne, Université de Perpignan Via Domitia, 66860 Perpignan cedex, France.
B USR 3278 CNRS-EPHE, Centre de Recherches Insulaires et Observatoire de l’Environnement (CRIOBE), BP 1013, Papetoai Moorea, French Polynesia.
C Mammal Research Institute, University of Pretoria, Pretoria, 0002, Republic of South Africa.
D Oceans Research, PO Box 1767, Mossel Bay, 6500, Republic of South Africa.
E Corresponding author. Email: matthias.vignon@univ-perp.fr
Marine and Freshwater Research 61(2) 163-169 https://doi.org/10.1071/MF09079
Submitted: 7 April 2009 Accepted: 4 July 2009 Published: 25 February 2010
Abstract
Shark feeding is widespread throughout tropical, subtropical and temperate marine ecosystems and gives rise to controversy because there is little consensus regarding its management. There are few comprehensive reports that consider how shark feeding with bait might impact local fishes, despite the development of this practice during the last few decades. Although shark feeding might theoretically have parasitological effects on local non-target fish species in the vicinity of feeding areas, this aspect has never been investigated. During an extensive parasitological survey conducted between 2005 and 2007, a total of 1117 fish belonging to six common grouper and snapper species were sampled throughout the entire north coast of Moorea Island (French Polynesia), encompassing three localities where feeding has occurred frequently since the 1990s. Parasites exhibited no spatial patterns except for the infections on the blacktip grouper (Epinephelus fasciatus). On this species, the prevalence of larval cestodes that parasitise sharks as adults and the intensity of their infestation were significantly higher around shark-feeding localities compared with non-shark-feeding localities. Our results suggest for the first time that although long-term shark feeding has parasitological implications, the impacts appear limited, only involve cestode larvae from one host species and do not seem to affect the health of the fish we studied.
Additional keywords: cestode, fish health, hepatosomatic index, Lutjanidae, Pacific, parasites, Serranidae.
Acknowledgements
We would like to thank K. Lafferty for revising this manuscript as well as other anonymous reviewers who made valuable suggestions to improve the manuscript. Financial support for this research was provided by CNRS (UMR 5244). CRIOBE facilities (UMR2978 CNRS EPHE) were used during this field expedition. Sampling was carried out according to Polynesian guidelines and policies of PGEM (Marine Space Management Plan) of Moorea.
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