In-situ microcosms, a tool for assessment of pesticide impacts on oyster spat (Crassostrea gigas)

• Published in: Ecotoxicology
• Main Authors: Stachowski-Haberkorn, Sabine, Quiniou, Françoise, Nedelec, Morgane, Robert, René, Limon, Gwendolina, De La Broise, Denis
• Other Authors: Laboratoire Universitaire de Microbiologie Appliquée de Quimper (LUMAQ), Université de Brest (UBO), Biogéochimie et Ecotoxicologie (IFREMER BE), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Laboratoire de Physiologie des Invertébrés (LPI), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Départemental d'analyse de conseil et d'expertise en Hygiène alimentaire, Eau et environnement et Santé Animale (IDHESA), IDHESA
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: microcosm; oyster; toxicity; pesticide; bentazon; epoxiconazole; [SDE]Environmental Sciences; Crassostrea gigas
• Online Access: https://hal.univ-brest.fr/hal-00675562; https://doi.org/10.1007/s10646-007-0190-9

International audience Effects of the herbicide Basamais (bentazon) and the fungicide Opus (epoxiconazole) on oyster spat (Crassostrea gigas) were assessed using in-situ microcosms in a field experiment lasting 13 days. Six-week-old hatchery spat (mean size 1.1 mm), previously collected on PVC plates, was immersed in glass bottles filled with 200 mu m filtered seawater. Bottles were maintained underwater at 6 m depth and their water content changed every other day. Growth, measured as shell area index increase, was 126 +/- 4% in the control bottles. While no growth differences were observed between control and individual pesticide treatments at 10 mu g l(-1), oysters treated with a mix of 10 mu g l(-1) Opus and 10 mu g l(-1) Basamais showed a 50% growth reduction compared with the control (P < 0.0001), suggesting a synergistic effect of these contaminants. Laboratory controls in microcosms maintained in a water bath with filtered natural light, were not significantly different from in-situ microcosm controls in the field, for organic weight content or growth. This in-situ experiment in microcosms allowed us to conclude that: (1) oyster spat can achieve significant growth in bottles immersed in situ without supplementary food; (2) this microcosm system is reliable and easy to use for environmental toxicity tests with C. gigas spat; (3) such microcosm systems can also be run in a laboratory water bath instead of more technically difficult immersed field experiments; (4) the synergistic effect observed here, at a concentration simulating a peak agricultural runoff event, suggests that the impacts of pesticides could be a real threat for oysters in estuarine areas.