Historic catches, abundance, and decline of Atlantic salmon Salmo salar in the River Elbe

Abstract

Fisheries statistics available from the River Elbe catchment since the middle of the 16th century onwards have been compiled and analyzed to assess 1. the spatial distribution and patterns of returning salmon, 2. the total abundance of the salmon stock, as well as 3. local impacts, reasons, and time lags of salmon decline. Catch data and fisheries statistics of up to 117 years from 67 sites have been compiled covering a period from 1552 to 1949. Although often incomplete, the available data revealed strong inter-annual spatial patterns of salmon catches. In particular, last or exceptional salmon records in distant tributaries or headwaters were significantly explained by flood events. In the River Elbe, the historical salmon harvest amounts of about 4,000 salmon annually are well above recent estimates of 300–400 returning salmon. The spatio-temporal patterns of salmon decline in the River Elbe catchment strongly indicate the importance of the historical spawning sites in the upstream river sections for salmon recovery as well as the resilience of large rivers against human disturbances. Both findings underline the need for a catchment approach in salmon rehabilitation including incorporation of and longitudinal connectivity to the upper catchment headwaters.