Original paper

Sediment textures and hydrogeomorphological characteristics of salmon and sea trout spawning habitats in Germany a contribution to river ecology

Dirksmeyer, Jochen; Brunotte, Ernst


The hydromorphological and sedimentological characteristics of spawning habitats of Atlantic salmon and sea trout were studied in selected rivers in Northern and Western Germany some 30 years after the initiation of restocking measures for these species. More than three quarters of the 189 spawning sites studied were located directly upstream from or within a riffle and were close to slow-flowing areas suitable for use as retreats. Only 20% of the spawning sites lay within a typical pool-riffle sequence. About 50-60% of the spawning substratum consisted of gravel (2-63 mm), but the overall sediment size composition ranged from clay to cobble. The highland spawning sites had a significantly lower proportion of fine sediment than the sites in the lowlands. For this reason more than half of the highland spawning grounds analysed had suitable or only slightly restricted conditions for salmonid eggs and larvae, while this was the case in just under a third of the sites studied in the North German Plain.