THE POPULATION EXPLOSION OF THE AMPHIPOD COROPHIUM-CURVISPINUM IN THEDUTCH LOWER RHINE

Densities of Corophium curvispinum Sars, 1895 collected from stones at two localities (Lobith and Nijmegen) in the Lower Rhine at a water de pth of 2-3 metres during 1992 were found to be very high. At both loca lities Corophium was the dominant macroinvertebrate, outnumbering all other species by many times. The population of the zebra mussel (Dreis sena polymorpha) was further reduced in 1992, because all stones am co vered with a 1-4 cm thick layer of muddy tubes of Corophium. Muddy mat erial including macroinvertebrates fixed by Corophium was found to be 61-609 g DW m-2 and 9-99 g AFDW m-2 stone surface.