11-year cycle of spawning time and growth of the whitefish (Coregonus lavaretus) of Lake Constance

Abstract

Over 90 years the beginning of spawning time of the whitefishCoregonus lavaretus of Lake Constance fluctuated in a wide range. A cycle of about 11 years is observed. Correlations of spawning time with sunspot activity (R), temperature, and age of spawners are found. Growth of the fishes in the first year of life correlates positively with R and year-class strength; growth in the second year correlates negatively with year-class strength and standing stock. It is assumed that the later the growing season ends the later the spawning season sets in.