Upstream and Downstream Migrations in Relation to the Reproductive Cycle and to Environmental Factors in the Amphipod, Gammarus Zaddachi

Abstract

The real identity has been studied of juvenile gamma- rids, that were found in the fresh-water tidal region of the River Slack (France), 3 to 4 km inland of the mouth of its estuary. At the outset, these juveniles were (on basis of their morphology) considered to belong to Gammarus salinus.