THE DISTRIBUTION OF JUVENILE FISHES IN A HYPEREUTROPHIC POND - CAN MACROPHYTES POTENTIALLY OFFER A REFUGE FOR ZOOPLANKTON

The distributions of juvenile cyprinids (roach Rutilus rutilus, rudd Scardinius erythrophthalmus, and their hybrids) and perch (Perca fluviatilis) were investigated in Priest Pot, a hypereutrophic pond in the English Lake District, in relation to macrophytes (Nuphar lutea), water temperature, and dissolved oxygen. Juvenile (0+, 1+ and 2+) cyprinids and perch were found both among dense, peripheral macrophytes and in the open water of the pond, although the cyprinids were apparently more abundant amongst the macrophytes. The implications of these findings for the viability of macrophytes as refuges for zooplankton are discussed in the context of biomanipulation.