Feeding behaviour of roach (Rutilus rutilus) larvae and the fry of perch (Perca fluviatilis) in Lake Lankau
Hammer, C.
Archiv fur Hydrobiologie 103(1): 61-74
1985
ISSN/ISBN: 0003-9136
Accession: 021030243
The feeding behavior of roach (R. rutilus) larvae (range: 5.5-24.9 mm) and perch (P. fluviatilis) juveniles (range: 7.7-93.0 mm) in their natural environment was investigated by periodic sampling using a fry trap, and by subsequent analysis of the gut contents. Results were expressed in 2 ways: as a percentage of fish which had ingested a particular category of food item and as a percentage of the numerical occurrence in the diet. Roach fry were highly selective. Copepods were seldom ingested, and the diet consisted chiefly of single cell green algae, cladocerans and rotifers. The roach fry diet also changed with time from Chydorus to Bosmina, as Chydorus disappeared from the littoral plankton, although there was an observed time lag in the response of the fry. Perch fry did not show elective behavior, and preyed on both cladocerans and copepods. Within the age group 0+, no evidence of cannibalism or piscivorous behavior was found.