An Overview on Geographical Distribution from Past Descriptions

Abstract

In the mid-nineteenth century, the European sturgeon (Acipenser sturio L, 1758) was proved to have been present in a significant proportion of the Western Palearctic region, i.e., Europe and North Africa. Of the 196 basin units investigated, 24 were selected for spawning by sexually mature individuals, and 44 were frequented by occasional vagrants. Its spatial distribution did not follow the classic “core–periphery” model noted for most European diadromous fish. Spawning basins were generally separated one from another by hundreds or even thousands of kilometers of coast. In these gaps, sturgeon were totally absent from inland waters, or occasionally migrants entered rivers, sometimes traveling far above the tidal limit, for exploration and feeding activities. Because of diverse anthropogenic regional pressures, the sturgeon’s range decreased drastically, and population disappearances were reported earlier in the twentieth century in the northern part of its range.