Dissolved oxygen concentration and emergence of sea trout fry from naturalredds in tributaries of the River Rhine

摘要

A total of 4289 sea trout Salmo trutta alevins swam up from six of eleven covered redds. They emerged only from those redds where the mean dissolved oxygen level was >6.9 mg l(-1) and the Sorting coefficient, an indicator of intragravel void space, was <5. These results are discussed in relation to field studies using artificially buried salmonid eggs but also in relation to the ongoing programme for the reintroduction of Atlantic salmon in tributaries of the River Rhine.