Does Manila Clam cultivation affect habitats of the engineer species Lanice conchilega (Pallas, 1766)?

Muséum National d'Histoire Naturelle (MNHN), Département Milieux et Peuplements Aquatiques, CNRS UMR 5178 BOME, CRESCO - Centre de Recherche et d'Enseignement sur les Systèmes Côtiers 38, Rue du Port-Blanc, 35801 Dinard, France.
Marine Pollution Bulletin (Impact Factor: 2.99). 07/2008; 56(8):1429-38. DOI: 10.1016/j.marpolbul.2008.04.046
Source: PubMed


The major French site of Manila clam Ruditapes philippinarum (Adams and Reeves, 1850) cultivation is located in the Chausey Archipelago where the associated practices are highly mechanized: every steps of production are made with tractor-driven machinery. The Manila clam concessions are concentrated on Lanice conchilega (Pallas, 1766) bioherms, which are known to increase alpha-diversity and to locally modify sediment dynamics. This study focus on the impacts of Manila clam cultivation on (i) the natural populations of L. conchilega and on (ii) the structure of the associated benthic assemblages during the different steps of the farming production cycle. We found that the L. conchilega populations are significantly affected within the concessions where their total abundances drastically decrease, their spatial patterns are modified and the associated benthic assemblages are significantly altered. Our results are discussed in a context of a sustainable management of the Manila clam cultivation in coastal areas.

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Available from: Nicolas Toupoint
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    • "The Chausey archipelago, located in the Normano-Breton Gulf (Normandy, France), is exposed to an extreme tidal regime, with tidal ranges up to 14 m during spring tides. This fragmented environment includes about 1500 ha of soft sediment tidal flat (Toupoint et al. 2008). Shellfish gathering on foot mainly concerns the tidal flats, where V. verrucosa is also more exposed to highly variable pressures of waves, emersion and temperature. "
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    ABSTRACT: In the Chausey archipelago, growth of the burrowing bivalve Venus verrucosa (Mollusca: Veneridae) has been shown to be highly variable between closely located sites (<1 km). To explain this small-scale spatial variability, we tested the trophic hypothesis using both fatty acid markers, and carbon and nitrogen stable isotopes (δ 13 C and δ 15 N). Environmental parameters, including substrate, were also analysed to discriminate their effects on potential trophic differences. Results of isotopic fractionation and lipid profiles of water column and digestive gland samples both showed a large contribution of phytoplankton to the diet of V. verrucosa. More surprisingly, the same results suggest that Phaeophyceae and Rhodophyceae macroalgae could contribute to the nutrition of V. verrucosa as dissolved exudates. Whereas site differences were not observed between the food sources of V. verrucosa, we showed that growth performance index was correlated to wave height. Thus, we hypothesized that the high local growth variability could be controlled by the hydrosedimentary dynamics. In addition, although no significant growth differences were found between intertidal and subtidal populations, better condition index and more total lipids were found in the digestive gland of intertidal V. verrucosa, suggesting potential compensatory growth mechanisms.
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    • "m -2 in the bay of Mont-Saint-Michel; Godet et al., 2008, 2009; Fig. 1(c)). The L. conchilega tube (diameter = 0.5 cm, total length up to 65 cm) is prolonged by sand-fringes which protrude from the sediment and impact the local hydrosedimentary environment (Toupoint et al., 2008). Above a threshold density, current velocities decrease within clusters, deposition of fine sediment particles is facilitated and mounds (up to 1 m high) are created (Féral, 1989; Zühlke, 2001). "

    Full-text · Article · Feb 2012
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    • "This species, native to the Western Pacific Ocean, has been introduced to several European countries and has since been naturalized in Italy, France, and Britain (Goulletquer & Héral, 1997). In Chausey, this species is cultivated, and the archipelago is the main national production site (Toupoint et al., 2008). "
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    ABSTRACT: The first updated list of the marine invertebrate fauna of the Chausey archipelago (Normand-Breton Gulf, France) is presented. All publications regarding the natural history of the area, as well as the existing collections of marine invertebrates from 1828 to 2008 were examined. A total of 769 species (including 245 Arthropoda, 197 Mollusca, 146 Polychaeta), have been recorded in this area covering 5000 ha. This species richness is largely the result of the complexity of benthic habitatsof the archipelago and its long history of field work, dating back to the 19 th Century. The historical data set of this region presents an opportunity to assess long-term changes in nearshore communities and to design conservation sites based on their scientific value. Résumé : Invertébrés marins de l'archipel des Iles Chausey : une liste commentée des données publiées de 1828 à 2008. La première liste actualisée des invertébrés marins de l'archipel des Iles Chausey (Golfe Normand-Breton, France) est proposée. L'ensemble des mansuscrits publiés de 1828 à 2008 relatifs à l'histoire naturelle du site, ainsi que différentes collections d'invertébrés marins ont été explorés. Un total de 769 espèces (parmi lesquelles 245 arthropodes, 197 mollusques, 146 polychètes), a été recensé sur ce site ne couvrant que 5000 ha. La complexité de la mosaïque d'habitats benthiques du site ainsi que son histoire naturaliste particulièrement riche, débutant dès le début du 19 ème siècle, expliquent largement cette richesse spécifique. Un tel jeu de données historiques sur un seul site donne une opportunité d'évaluation des changements à long terme sur le littoral et souligne l'enjeu de conservation d'un site au regard de sa valeur scientifique.
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