A note on the age composition, growth rate and food of perch Perca fluviatilis (L.) in four eutrophic lakes, England

Abstract

The perch populations of all lakes sampled are characterised by high growth rates (l± 320–410 mm) and year‐class instability. The concurrence of four year‐classes (1970,1973,1975and 1976) in three of the lakes is good evidence for climatic control of recruitment. Poor recruitment in Rostherne Mere during 1973 is attributed to the effects of cannibalism. An increase in the growth rate of young fish (0+) in all lakes during 1975 and 1976 is noted. The relatively poor growth of perch in Rostherne Mere is a consequence of the low specific growth rate there during the first year of life. An outbreak of the ‘perch‐disease’ killed most of the adult perch present in 1975 in Rostherne Mere.