Directive Cadre sur l’Eau : les pressions anthropiques et leur impact sur les indicateurs de l’état écologique des masses d’eau littorales de la façade Manche-Atlantique. Synthèse bibliographique

Within the European water framework directive (WFD), the status assessment of littoral waters is based both on the chemical quality and on the ecological quality of each water body. Quality elements enabling to assess the ecological status of a water body are, among other things, biological quality elements (phytoplankton, macroalgae, angiosperms, benthic invertebrates, fish), for each of which the member states have developed quantitative indicators. This document is one of the deliverables of a multi-annual study intended to characterize the sensitivity of these biological indicators towards the various anthropogenic pressures exerted on the French Atlantic and Channel coast: ultimately, the goal is to establish a quantitative and predictive relationship, statistically robust, between the WFD indicators used along the French channel and Atlantic coastline, and various anthropogenic pressures acting on these coasts. The aim of the WFD is indeed to restore or maintain a good chemical and biological quality of coastal waters, and thus to limit the impact of human activities potentially responsible for the degradation of ecosystems. This understanding of the linkages and interactions existing between anthropogenic pressures and ecological status of water bodies is therefore essential to identify priorities for action (challenges, substances ...), prioritize actions to implement within restoration programs (technical, fiscal, financial), but also to be able to communicate constructively and persuasively in talks between managers and the various stakeholders of coastal regions. Using the DPSIR methodology, this literature analysis has permitted to identify, for each WFD biological quality element (except fish), which pressures (or pressure types) are potentially relevant in the light of their impact on the indicators of the ecological status of water bodies. Some metrics and indicators of anthropogenic pressures used in the literature to characterize the sensitivity of the biological quality elements, within quantitative approaches, were also identified. It is also clear from this review that the biological quality elements can be particularly sensitive to intrinsic environmental conditions, and therefore to certain changes related to natural phenomena occurring at large scales (e.g. climate change, paroxysmal climate episode...). Therefore, when one is interested in the sensitivity of biological indicators to different anthropogenic pressures, two factors can complicate the analysis and are likely to weaken the resulting statistical relationships: on the one hand, the variability of biological responses depending on the natural context and, on the other hand, interactions (so called synergistic effects) between different types of anthropogenic pressures and the alterations they can generate.

Stockage des poissons fumés et ou séchés : cas de Oreochromis niloticus " Fiha saly " malgache

During storage of smoke-dried fish, various biochemical reactions can occur; they will result in product acceptability or rejection. To determine these changes, pH and humidity were measured and molds were counted on smoke-dried fish stored for 6 months. A sensory analysis was also conducted to assess the quality of the products. Infestations and losses linked to it have been estimated by counting the insects and weighing of fish batches over time. The variability in the quality of smoke-dried fish depending on the time of purchase and storage was also integrated with our study. Biochemical reactions are mainly oxidation phenomena which result in a decrease of pH and release of spoilage odors such as rancid odor (> 1.5/ 3) or sulfur, acid and moldy odors. The growth of mold (1- 36 CFU / g) due to the reabsorption of water by fish contributes to this olfactory and visual spoilage. Beyond 90 days of storage, smoke-dried fish bought in the dry season begins to be rejected (> 2/3), while the fish bought in the wet season is at the limit of acceptability (2/3) even at the beginning of storage. During the first 90 days of storage, the insect infestation generates between 10 and 60 % of losses. A salt content of 8 % appears to be effective against the infestation but contributes to the deterioration of the product when stored in rooms with higher than 65 % relative humidity.