AB 3:101-109 (2008)  -  doi:10.3354/ab00073

Remodeling of membrane lipids in gills of adult hard clam Mercenaria mercenaria during declining temperature

Geneviève J. Parent1, Fabrice Pernet2,3,*, Réjean Tremblay1, Jean-Marie Sévigny4, Marc Ouellette5

1Institut des sciences de la mer, Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski, Quebec G5L 3A1, Canada
2Institut de Recherche sur les Zones Côtières, 232-B rue de l’Église, Shippagan, New Brunswick E8S 1J2, Canada
3IFREMER, Laboratoire environnement Ressources, Avenue Jean Monet, BP 171, 34203 Sète Cedex, France
4Institut Maurice Lamontagne, Pêches & Océans Canada, Mont-Joli, Quebec G5H 3Z4, Canada
5Pêches & Océans Canada, Région du Golfe, Moncton, New Brunswick E1C 9B6, Canada
*Corresponding author. Email:

ABSTRACT: In a previous study, a major remodeling of lipids, consistent with the theory of homeoviscous adaptation, was observed in the juvenile hard clam Mercenaria mercenaria during a temperature reduction from 24 to –1°C. In addition, the lipid remodeling varied between genetically distinct lines of hard clams. The present study examined whether adult hard clams originating from different locations and a selectively bred variety show differences related to their genetic characteristics in the remodeling of lipids that normally occur during decreasing temperatures. Wild hard clams from 4 locations in Atlantic Canada and the selectively bred M. mercenaria var. notata were held at an aquaculture growout site located at the northern distribution limit of the species in the Gulf of St. Lawrence from August to December 2006. Gills were sampled monthly for lipid analyses. Hard clams from the 5 groups showed an increase in the unsaturation index, mainly attributable to 22:6n-3 and 20:5n-3 as temperature decreased during the fall, followed by an increase in the phospholipid to sterol ratio in December. Although hard clams from the wild showed a lower unsaturation index than the selectively bred clams, there was no effect of location on the lipid remodeling. This result coincided with low genetic differentiation among hard clams from the 5 groups. Interestingly, the levels of 20:5n-3, 20:4n-6 and 22:6n-3—3 fatty acids obtained from the diet—were generally lower in the environment compared to the levels in hard clams, thus suggesting some mechanisms for the selective incorporation of these fatty acids in hard clams.


KEY WORDS: Acclimatization · Allozymes · Bivalve · Fatty acid · Food · Intraspecific variation · Membrane lipid · Phospholipid · Sterol


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Cite this article as: Parent GJ, Pernet F, Tremblay R, Sévigny JM, Ouellette M (2008) Remodeling of membrane lipids in gills of adult hard clam Mercenaria mercenaria during declining temperature. Aquat Biol 3:101-109

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