The Life+ Allis shad project’s main objective is, besides the continuation and optimization of the measures aiming on the re-introduction of the Allis shad to the Rhine system, the identification of the causes for the current decline of the Allis shad populations in the Gironde-system in the Southwest of France, which furthermore serves as the donor population for stocking the Rhine system.
The number of adult Allis shad, which migrate upstream the Garonne, the Dordogne and their tributaries in order to spawn, has drastically decreased from 2006 onwards before the measures of the previous LIFE project have been started. Regardless of a moratorium, which prohibits the traditional Allis shad fisheries in the Gironde watersheds, the numbers of returners are on an alarming low level. The priority objective of the LIFE+ Allis shad project are thus to identify the reasons behind the quite unexpected collapse of the stocks and as possible the initiation of countermeasures.
Monitoring studies focusing on the identification of migratory routes and patterns of downstream migrating young-of-the-year (YOY) Allis shad, as well as those of adults, which are expected to return to the Rhine system from 2013 onwards, are carried out parallel in the German and Dutch part of the project area. These results will help to optimize the strategies aiming on the conservation and reintroduction of European Allis shad populations. A further objective is to establish techniques for keeping Allis shad in captivity and until they reach maturity. Such ex-situ stocks shall on a medium term scale help to make the exploitation of returners in the wild for breeding purposes increasingly unnecessary and moreover to select features contributing to the adaptation towards the new environment.
In conclusion, the LIFE+ project shall not only contribute to protect the remaining Allis shad populations in Europe from suffering a similar fate as in the Rhine basin a hundred years ago, which led to the species disappearance from the Rhine and large parts of the former distribution range, but also to promote the return of the Allis shad to the Rhine system and thus to serve as a template for future reintroduction and conservation projects for the Allis shad and other species of migratory fish.