Spawning migration and larval drift of anadromous North Sea houting (Coregonus oxyrinchus) in the River IJssel, the Netherlands

Abstract

AbstractAnadromous North Sea houting (NSH, Coregonus oxyrinchus) was historically distributed in the Wadden Sea extending from Jutland (Denmark) to the Schelde delta (Netherlands). The species has been considered extinct in the Rhine since the 1940s; however, a successful re‐introduction programme re‐established a self‐reproducing population. Telemetry data of adult NSH (NEDAP TRAIL System®) were used for a first description of the timing of spawning migrations of NSH in winter, but also suggested that the River IJssel, a lower branch of the Rhine, may serve as spawning ground. This was further proven in spring 2010 with drift net catches of 218 freshly hatched NSH larvae sampled directly upstream from Kampen, where the IJssel discharges into Lake IJsselmeer. These larvae did not differ between controls from a hatchery that were about 12 h of age, indicating that the drifting larvae of NSH must have hatched in upstream areas of the River IJssel.