DIRECT ESTIMATION OF FOOD-CONSUMPTION OF JUVENILE FISH IN A SHALLOW INLET OF THE SOUTHERN BALTIC

The species composition and feeding behaviour of fish larvae and juven iles was investigated in a shallow inlet of the Southern Baltic. The a im of the study was to examine if there was a predatory impact of youn g fish on the observed annual collapse of the copepod population. Domi nant fish species were herring (Clupea harengus), perch (Perca fluviat ilis) and roach (Rutilus rutilus). Roach larvae preferred shallower ar eas, whereas young herring and perch were found in open water. Highest consumption values were always observed in the evening. By computing complete evacuation of the digestive tract in approximately 3.5 hours, daily consumption in percent of fish fresh weight was 1.3, 4.7 and 5. 5 % for young herring, roach and perch, respectively. The impact of yo ung fish on the dynamics of the population of the copepod species Eury temora affinis is negligible.