Best Management Strategies for Sustainable Giant Clam Fishery in French Polynesia Islands: Answers from a Spatial Modeling Approach

The giant clam Tridacna maxima has been largely overexploited in many tropical regions over the past decades, and was therefore listed in appendix II of the Convention of International Trade in Endangered Species (CITES) in 1985. In French Polynesia, several atolls and islands harbor the world’s highest stocks of giant clams in very shallow and accessible areas, which are therefore highly vulnerable to fishing pressure. The local fishery authority (i.e., Direction des Resources Marines or “DRM”) implemented several management schemes in 2002 to control and regulate fishing pressure. However, for further decisions DRM was missing a sensitivity analysis on the effectiveness of the possible management actions. Here, we report on the use of a deterministic Viable Population Analysis (VPA) and spatially-explicit age-based population model that simulated the 30-year trajectory of a Tridacna maxima stock under different management approaches. Specifically, given various scenarios of intra-island larval dispersal, we tested which of No-take-Areas (NTAs), rotational closures, size limits, quotas, and restocking schemes would lead to the highest future stocks in Tubuai and Raivavae, two exploited islands of the Austral archipelago. For both islands, stock abundances were estimated in 2004/2010 and 2005/2010 respectively, and natural mortalities were assessed previously only in Tubuai. When compared to field data, the model successfully predicted the 2010 stocks for Tubuai, but proved to be less reliable for Raivavae, where natural mortality rates may well be different from those on Tubuai. For Tubuai, the spatial model suggested that reducing fishing effort (through fixed quotas) and banning fishing below the 12 cm size limit (as currently implemented) were the most effective management actions to sustain T. maxima populations into the future. Implementing NTAs was of poor effectiveness. NTAs increased giant clam stock inside the protected area, but also increased overfishing in the neighboring areas, and were ineffective overall.

[1]  S. Andréfouët,et al.  Comanaging small-scale sea cucumber fisheries in New Caledonia and Vanuatu using stock biomass estimates to set spatial catch quotas , 2013, Environmental Conservation.

[2]  S. Andréfouët,et al.  Climate variability and massive mortalities challenge giant clam conservation and management efforts in French Polynesia atolls , 2013 .

[3]  Andrew H Baird,et al.  Comanagement of coral reef social-ecological systems , 2012, Proceedings of the National Academy of Sciences.

[4]  Pedro Afonso,et al.  Effects of no-take area size and age of marine protected areas on fisheries yields: a meta-analytical approach , 2011 .

[5]  J. Prince,et al.  Evidence of large, local variations in recruitment and mortality in the small giant clam, Tridacna maxima, at Ningaloo Marine Park, Western Australia , 2011 .

[6]  D. Apte,et al.  Monitoring densities of the giant clam Tridacna maxima in the Lakshadweep Archipelago , 2010 .

[7]  H. Darius,et al.  Ciguatera risk management in French Polynesia: the case study of Raivavae Island (Australes Archipelago). , 2010, Toxicon : official journal of the International Society on Toxinology.

[8]  S. Andréfouët,et al.  Using very high resolution remote sensing for the management of coral reef fisheries: review and perspectives. , 2010, Marine pollution bulletin.

[9]  S. Andréfouët,et al.  A comparison of two surveys of invertebrates at Pacific Ocean islands: the giant clam at Raivavae Island, Australes Archipelago, French Polynesia , 2009 .

[10]  Shane Abeare,et al.  Fishing effort redistribution in response to area closures , 2009 .

[11]  D. Kaplan.  Fish life histories and marine protected areas: an odd couple? , 2009 .

[12]  P. Barber,et al.  Phylogeography and Limited Genetic Connectivity in the Endangered Boring Giant Clam across the Coral Triangle , 2008, Conservation biology : the journal of the Society for Conservation Biology.

[13]  R. Hilborn,et al.  Economics of Overexploitation Revisited , 2007, Science.

[14]  E. Barbier,et al.  Impacts of Biodiversity Loss on Ocean Ecosystem Services , 2006, Science.

[15]  Joshua E. Cinner,et al.  A Comparison of Marine Protected Areas and Alternative Approaches to Coral-Reef Management , 2006, Current Biology.

[16]  Camilo Mora,et al.  Coral Reefs and the Global Network of Marine Protected Areas , 2006, Science.

[17]  R. Leaf,et al.  Elasticity analyses of size-based red and white abalone matrix models: management and conservation. , 2006, Ecological applications : a publication of the Ecological Society of America.

[18]  C. Dytham,et al.  Effects of habitat characteristics and sedimentation on performance of marine reserves in St. Lucia , 2006 .

[19]  Stéphanie Mahévas,et al.  Spatially explicit fisheries simulation models for policy evaluation , 2005 .

[20]  A. Vincent,et al.  Enhancing Sustainability of the International Trade in Seahorses with a Single Minimum Size Limit , 2005 .

[21]  S. Andréfouët,et al.  Extraordinarily high giant clam density under protection in Tatakoto atoll (Eastern Tuamotu archipelago, French Polynesia) , 2005, Coral reefs.

[22]  N. Sayre.  Interacting Effects of Landownership, Land Use, and Endangered Species on Conservation of Southwestern U.S. Rangelands , 2005 .

[23]  B. Halpern,et al.  CONFOUNDING EFFECTS OF THE EXPORT OF PRODUCTION AND THE DISPLACEMENT OF FISHING EFFORT FROM MARINE RESERVES , 2004 .

[24]  B. Halpern,et al.  Review Paper. Matching marine reserve design to reserve objectives , 2003, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[25]  John Sabo,et al.  Morris, W. F., and D. F. Doak. 2003. Quantitative Conservation Biology: Theory and Practice of Population Viability Analysis. Sinauer Associates, Sunderland, Massachusetts, USA , 2003 .

[26]  B. Worm,et al.  Rapid worldwide depletion of predatory fish communities , 2003, Nature.

[27]  O. Cacho,et al.  A growth model for giant clams Tridacna crocea and T. derasa , 2003 .

[28]  S. Planes,et al.  High variability of genetic pattern in giant clam (Tridacna maxima) populations within French Polynesia , 2002 .

[29]  Juan Carlos Castilla,et al.  Latin American benthic shellfisheries: emphasis on co-management and experimental practices , 2001, Reviews in Fish Biology and Fisheries.

[30]  M. Hadfield,et al.  Why and how marine-invertebrate larvae metamorphose so fast. , 2000, Seminars in cell & developmental biology.

[31]  J. Bell,et al.  Growth and survival of the giant clams, Tridacna derasa, T. maxima and T. crocea, at village farms in the Solomon Islands , 1998 .

[32]  J. Bohnsack.  Application of marine reserves to reef fisheries management , 1998 .

[33]  Juan Carlos Castilla,et al.  Small-scale benthic fisheries in chile: on co-management and sustainable use of benthic invertebrates , 1998 .

[34]  M. J. Maceina,et al.  Analyses of the Sauger Fishery with Simulated Effects of a Minimum Size Limit in the Tennessee River of Alabama , 1998 .

[35]  J. E. Eckman.  Closing the larval loop: linking larval ecology to the population dynamics of marine benthic invertebrates , 1996 .

[36]  R. Osman,et al.  The influence of resident adults on larval settlement: experiments with four species of ascidians , 1995 .

[37]  D. Reed,et al.  Conceptual Issues Relevant to Marine Harvest Refuges: Examples from Temperate Reef Fishes , 1993 .

[38]  Michael Colvin.  Evaluation of Minimum‐Size Limits and Reduced Daily Limits on the Crappie Populations and Fisheries in Five Large Missouri Reservoirs , 1991 .

[39]  C. Villanoy,et al.  Fishing mortality rates of giant clams (Family Tridacnidae) from the Sulu Archipelago and Southern Palawan, Philippines , 1988, Coral Reefs.

[40]  J. Schnute,et al.  An Experimental and Statistical Approach to the Question: Is CPUE an Index of Abundance? , 1986 .

[41]  K. J. Sainsbury,et al.  Population dynamics and fishery management of the paua, Haliotis iris , 1982 .

[42]  Martial Schtickzelle,et al.  Pierre-François Verhulst (1804-1849). La première découverte de la fonction logistique , 1981 .

[43]  S. Jameson.  Early Life History of the Giant Clams Tridacna crocea Lamarck, Tridacna maxima (Roding), and Hippopus hippopus (Linnaeus) , 1976 .

[44]  H. Mergner,et al.  Morphologie, Ökologie und Zonierung von Korallenriffen bei Aqaba, (Golf von Aqaba, Rotes Meer) , 1974, Helgoländer wissenschaftliche Meeresuntersuchungen.

[45]  M. Labarbera.  Calcification of the first larval shell of Tridacna squamosa (Tridacnidae: Bivalvia) , 1974 .

[46]  P. H. Leslie.  SOME FURTHER NOTES ON THE USE OF MATRICES IN POPULATION MATHEMATICS , 1948 .

[47]  P. H. Leslie.  On the use of matrices in certain population mathematics. , 1945, Biometrika.

[48]  Philippa J. Cohen,et al.  Sustaining small-scale fisheries with periodically harvested marine reserves , 2013 .

[49]  J. Clavier,et al.  Multi-scale distribution and dynamics of bivalve larvae in a deep atoll lagoon (Ahe, French Polynesia). , 2012, Marine pollution bulletin.

[50]  S. Andréfouët,et al.  Bivalve larvae transport and connectivity within the Ahe atoll lagoon (Tuamotu Archipelago), with application to pearl oyster aquaculture management. , 2012, Marine pollution bulletin.

[51]  Annie Yau.  Size-Based Approaches to Modeling and Managing Local Populations: A Case Study Using an Artisanal Fishery for Giant Clams, Tridacna maxima , 2011 .

[52]  P. Todd,et al.  THE DISTRIBUTION AND STATUS OF GIANT CLAMS (FAMILY TRIDACNIDAE) - A SHORT REVIEW , 2010 .

[53]  G. Pierce,et al.  ICES Journal of Marine Science, Special Edition: Cephalopod life history, populations and environiment. Selected papers of CIAC'09 , 2010 .

[54]  Gerjan J. Piet,et al.  Using MPAs to address regional-scale ecological objectives in the North Sea: modelling the effects of fishing effort displacement , 2009 .

[55]  S. Andréfouët,et al.  Planning the use of fish for food security in the Pacific , 2009 .

[56]  A. Charles,et al.  Human dimensions of Marine Protected Areas , 2009 .

[57]  Boris Worm,et al.  Services Impacts of Biodiversity Loss on Ocean Ecosystem , 2009 .

[58]  S. Andréfouët,et al.  The giant clam Tridacna maxima communities of three French Polynesia islands: comparison of their population sizes and structures at early stages of their exploitation , 2006 .

[59]  Serge Andréfouët,et al.  The remarkable population size of the endangered clam Tridacna maxima assessed in Fangatau Atoll (Eastern Tuamotu, French Polynesia) using in situ and remote sensing data , 2005 .

[60]  H. Roa-Quiaoit.  Ecology and culture of giant clams (Tridacnidae) in the Jordanian sector of the Gulf of Aqaba, Red Sea , 2005 .

[61]  W. Hamner.  Intraspecific competition in Tridacna crocea, a burrowing bivalve , 2004, Oecologia.

[62]  D. Doak,et al.  Book Review: Quantitative Conservation biology: Theory and Practice of Population Viability analysis , 2004, Landscape Ecology.

[63]  S. Andréfouët,et al.  Mass mortality of macrobenthic communities in the lagoon of Hikueru atoll (French Polynesia) , 2001, Coral Reefs.

[64]  L. Addessi.  Giant clam bleaching in the lagoon of Takapoto atoll (French Polynesia) , 2001, Coral Reefs.

[65]  Carl J. Walters,et al.  Impacts of dispersal, ecological interactions, and fishing effort dynamics on efficacy of marine protected areas : How large should protected areas be ? , 2000 .

[66]  Loana Addessi.  Les principaux bivalves de l'atoll de takapoto (polynesie francaise) sont-ils des competiteurs trophiques de l'huitre perliere ? : approche ecophysiologique , 1999 .

[67]  J. Lucas.  The biology, exploitation, and mariculture of giant clams (Tridacnidae) , 1994 .

[68]  P. S. Maitland,et al.  Fisheries and aquaculture. , 1994 .

[69]  R. Galzin,et al.  Impact of tourism-related fishing on Tridacna maxima (Mollusca, Bivalvia) stocks in Bora-Bora Lagoon (French Polynesia) , 1993 .

[70]  Sandra E. Shumway,et al.  Scallops : biology, ecology, and aquaculture , 1991 .

[71]  Willem Wijnstekers,et al.  ON INTERNATIONAL TRADE IN ENDANGERED SPECIES OF WILD FAUNA AND FLORA , 2000 .

[72]  B. Salvat.  La faune benthique du lagon de l'atoll de Scilly, archipel de la Société in Récifs et lagons de Polynésie française. , 1983 .

[73]  M. Schtickzelle.  [Pierre-Francois Verhulst (1804-1849): the discovery of the logistic law of growth] , 1981 .

[74]  Goldsmith Ei.  The Convention on International Trade in Endangered Species of Wild Fauna and Flora. , 1978 .