Migratory fish: the allis shad in the Rijn and Maas
The allis shad is a migratory fish that used to be found in the large rivers but is now extinct in the Netherlands.
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There was a thriving commercial fishery of the allis shad in the Rijn and Maas until about 1910. In the 1930s, however, the allis shad all but died out because of the worsening water quality, the loss of suitable spawning grounds and the fact that the fish were unable to negotiate the weirs and sluices in the river during their annual migration to spawn. Between 1969 and 1993 there were 4 recorded catches of allis shad. The fish were presumed to have arrived from rivers elsewhere in Europe, or to be escapees from fish farms or to be deliberate introductions. To date, the allis shad has not returned to Dutch waters even though the water quality has improved and fish passages have been constructed.
The allis shad is on the Red List of freshwater fishes.
