On 24 June, 2008, the time had come. On the banks of the Rhine in Düsseldorf-Oberkassel, the North Rhine Westphalia Minister of the Environment, Eckhard Uhlenberg, and his colleague from Hesse, Wilhelm Dietzel released the first allis shad in the Rhine in a big media event. This year, more than 500,000 allis shad in total were exposed to the previously mapped areas in North Rhine Westphalia and Hesse.
Image: Release of the allis shad by the Minister of the Environment Photograph: H. Schulze-Wiehenbrauck [ Enlarge photo ]
Image: The first allis shad stock in the Rhine. From the left: Project coordinator Dr. Peter Beeck, Wilhelm Dietzel, the Minister of the Environment of Hesse, the French Consul General from Düsseldorf, Gilles Thibault, and Eckhard Uhlenberg, the Minister of the Environment of North Rhine Westphalia. Photograph: E. Braun [ Enlarge photo ]
For a re-introduction project of this type it is very important that all stocked animals are marked. Only by doing so is it possible to evaluate the success of the project. In the Life project the ear stones (otoliths) of allis shad larvae will be chemically stained. The chemical is placed into the rearing tanks and within a couple hours the staining substance incorporates into the bony structure. Under a microscope and with fluorescent light the mark is visible as a green ring.
Left: Position of the ear stones (otoliths) in the allis shad larvae [ Enlarge Photo ]
Middle: Ear stone under normal light showing daily growth rings [ Enlarge Photo ]
Right: Ear stones with mark (green ring) under fluorescent light [ Enlarge Photo ]
