The distribution and growth of coarse fish in gravel‐pit lakes in south‐east England

SUMMARY. Age and growth rates of the coarse fish of thirty‐nine gravel‐pit lakes in south‐east England are compared. Species composition was very variable, the commonest species being roach (Rutilus rutilus), bream (Abramis brama), tench (Tinca tinca), perch (Perca fluviatilis) and pike (Esox lucius). Two main kinds of fish community were identifiable from the survey: (1) those consisting of a mixture of cyprinids, usually roach and bream; and (2) those in which cyprinids were rare or absent and the fish community was composed of perch and pike. The majority of the lakes fell into the first category. Comparison of growth curves derived by back‐calculation showed that, in all species, variation occurred from lake to lake and from year to year. The majority of gravel‐pit lake fishes had ‘medium’ growth rates when compared with published data by other workers on different waters. Seasonal growth of roach infected with plerocercoids of Ligula intestinalis was observed at monthly intervals. Annulus formation on the scales of these fish occurred at the onset of growth in May. The heavy Ligula burden in 89% of these fish had not caused the formation of any additional or false rings.