Last update on 27/04/2018

Assessing fish health: the missing cornerstone in ecological impact assessment and management / Florian Mauduit


Thesis jointly supervised by the University of Western Brittany

PhD jointly supervised by: Guy Claireaux, professor at University of Western Brittany

Committee: Craig Franklin, David McKenzie, Michel Auffret, Annabelle Nicolas-Kopec, Philippe Lemaire, Stéphane Le Floch


Abstract: Growth of human population and associated intensification of human activities is putting considerable pressure on coastal marine ecosystems. To assess anthropogenic impact on these ecosystems, substantial efforts have been devoted to the development of biomarkers. Despite a potential for a broad application range, most commonly used biomarkers target effects at sub-organismal organizational level (molecules, cells or tissues) and very few are liable to indicate impacts at organism or higher organizational levels. On the other hand, although too far removed from causal events to constitute early warning signals of environmental stress, high-level organizational biomarkers are of considerable relevance to human activities, economy and well-being. They are indeed the integrative result of the environmental history of an organism and, at the same time, reflect their vulnerability and resilience to changes in their living conditions. This view is corroborated by the recent revision of the concept of animal health, which nowadays incorporates the latent effects of past living conditions, the consequences of past exposures and experiences and the cumulative consequences of these effects. The joint use of high organizational levels markers and the concept of health could help overcome the failure of current biomarkers to provide ecologically relevant information. In this context, the objectives of my thesis were 1) to develop a methodology to assess fish health; 2) to investigate the underlying mechanisms and confounding factors of the performances measured and 3) to verify the applicability of our approach through two case studies.Throughout these researches, we demonstrated that hypoxia tolerance, temperature susceptibility and swimming performances are promising biomarkers of fish health. Their responses are stable over time, predictive of fish survival in the field and sensitive to an exposure to dispersant-treated oil. Also, application of this methodology to case studies demonstrated that our approach is generalizable to different contexts and that it provides operational information easily transferable to socio-economic sectors and general public.


Bibliographical reference: http://doc.cedre.fr/index.php?lvl=notice_display&id=9820

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