Rheotaktisches Verhalten einiger Gammarus-Arten bei verschiedenem Sauerstoffgehalt des Wassers

Abstract

An experimental vessel has been developed which makes it possible to observe the behaviour of gammarids and other aquatic invertebrates in various water current speeds and oxygen concentrations. Studies have been conducted with the following limnic and brackish-water amphipods:Gammarus pulex (L.), G. roeseliGervais, G. fossarumKoch, G. tigrinusSexton and G. salinusSpooner. In adequate oxygen concentrations, the gammarids tested show a moderate positive rheotaxis. Lethal and sublethal oxygen concentrations, however, lead to negative rheotaxis. The maximum degree of upstream movement is attained in the region of the critical oxygen concentration. Under the experimental conditions (15° C, water current 5 cm/sec), these maxima vary according to species. The maximum occurred at 2.7 mg O2/l for G. pulex, 3.1 mg O2/l for G. roeseli, 3.5 mg O2/l for G. tigrinus, and 5.3 mg O2/l for G. fossarum. No such maximum was found for G. salinus. Oxygen deficit causes G. salinus to move downstream at 2.5 mg O2/l. © 1973 Biologischen Anstalt Helgoland.