Mn labelling of living oysters: Artificial and natural cathodoluminescence analyses as a tool for age and growth rate determination of C. gigas (Thunberg, 1793) shells
|Author(s)||Lartaud Franck1, 2, De Rafelis Marc1, Ropert Michel3, Emmanuel Laurent1, Geairon Philippe4, Renard Maurice1|
|Affiliation(s)||1 : Univ Paris 06, Lab Biomineralisat & Environm Sedimentaires, ISTeP, UMR 7193, F-75252 Paris 05, France.
2 : CNRS, IUEM UBO, Lab Sci Environm Marin LEMAR, UMR 6539, F-29280 Plouzane, France.
3 : IFREMER, Lab Environm Ressource Normandie, F-14520 Port En Bessin, France.
4 : IFREMER, Lab Environm Ressource Pertuis Charentais, F-17390 La Tremblade, France.
|Source||Aquaculture (0044-8486) (Elsevier Science Bv), 2010-02 , Vol. 300 , N. 1-4 , P. 206-217|
|WOS© Times Cited||33|
|Keyword(s)||Oyster shells, Crassostrea gigas, Manganese markings, Cathodoluminescence, Seasonal growth patterns|
|Abstract||We developed a growth model for Crassostrea gigas oyster shells based on the use of in situ temporal manganese markings to calibrate natural cathodoluminescence (CL) changes in the shell hinge sections. A 30 min to 4-h exposure period with Mn2+ (90-120 mg l(-1)) was sufficient to create a detectable mark in the shells. This makes the Mn2+ markings the fastest mollusc shells marking technique to date. The natural CL from juvenile and adult shells cultured in four standard shellfish-farming locations along the English Channel and French Atlantic coasts, exhibited a seasonal pattern (maximum CL intensity occurring during summer periods, minimum CL intensity occurring during winter). Hydrobiological data recorded at Baie des Veys site allows us to attribute the seawater temperature as the main parameter controlling CL of shells. Chlorophyll a and seawater manganese concentration were not decisive in the luminescence intensity of the shells. A relationship between oyster hinge growth and the length of shells makes the umbo investigations a promising tool for oyster-farming and/or wild stock assessments. Shell growth varied at spatial and temporal scales (higher growth rates were observed during summer-autumn and lower during the winter period), depending on seawater temperature changes. Sub-monthly Mn2+ markings support the fact that shell deposition can occur under temperatures below 6 degrees C, which has to be taken into account for both shellfish production and environmental monitoring derived from chemical compositions of the shells. Finally, our results point out the efficiency of age and shell growth rate determination by CL analysis in further shellfish ecosystem researches.|