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Protect biodiversity





From Wels catfish to eels and minnows, Onema personnel have monitored fish populations in rivers and lakes for over 20 years. Since 2007, these operations have been carried out in the framework of the WFD monitoring programmes that call on a network of over 1 500 long-term monitoring points spread throughout France and the overseas territories. Studies on the structure of fish communities use electrofishing or nets to capture and inventory individual fish. The captured fish are identified and measured. The obtained data are then merged with other information on «quality elements» such as physical-chemical aspects and hydromorphology to assess the ecological status of water bodies.

The long data series on fish communities collected by Onema personnel are also of great value for research. The long-term monitoring data, made available to research organisations, provide information on trends in fish communities and can be used to study the impact of climate change on the distribution of populations. This extremely productive research highlights the great value of the long data series produced by Onema for efforts to understand and restore aquatic biodiversity.

  • Trends in fish populations How have fish populations, confronted with modified habitats, climate change, alien species, etc., changed over the past 20 years in continental France?

    Understanding and reducing the impact of river structures to save the eel Over a period of three years, the Eels & Installations R&D programme, a partnership between Onema, Ademe and hydroelectric companies, set up 18 research projects.

    Ecosystem management of coastal marshes In 2006, a partnership between the town of Braud-et-Saint-Louis, ONCFS and Onema was set up at the Terres d’oiseaux ornithological park. The goal was to experiment new management techniques designed to improve environmental operation for fish species, notably eels, while taking fully into account the other site requirements.

    An innovative solution for the Poutès dam On 6 October 2011, the Ecology ministry officially announced the partial razing of the Poutès hydroelectric dam on the Allier river. This solution, which puts an end to over 20 years of disputes on the need to remove the dam, will enable the passage of salmon while maintaining 90% of the hydroelectric production. The new system was designed by the EDF centre for hydraulic engineering in conjunction with the engineers at the Onema Ecohydraulic centre in Toulouse.

    A bypass on the Cher river In the middle of the city of Tours, a bypass around the Rochepinard weirs on the Cher river was put into operation in April 2011.

    The police for water and aquatic environments takes action for biodiversity The water police plays a key role in preserving biodiversity by preventing damage to aquatic environments (destruction of spawning grounds, obstacles to the passage of migratory fish, etc.) and by stopping organised poaching.

    Preserving large migratory fish and fighting invasive species 2010 was declared the International year of biodiversity. The year stood out for Onema with three major events, namely its participation in formulating the national management strategy for migratory fish, its collaboration with the "migrator" associations and the national fishing federation in France to set up a national database on migratory fish and, finally, efforts with Cemagref to fight invasive species.