BIOCHEMICAL-GENETIC STUDY OF SYMPATRIC LAKE CONSTANCE WHITEFISH (COREGONUS-LAVARETUS) POPULATIONS - BLAUFELCHEN AND GANGFISCH

Ripe females of whitefish (Coregonus lavaretus) of Lake Constance were caught at spawning time on their known spawning sites. Fish were exam ined for their size, gill-raker number, and for their egg dry weight. On the basis of their spawning sites as well as on correlation between body weight and egg weight, fish were allocated at one of the two sym patric populations: nearshore spawning ''Gangfisch'' or pelagic spawni ng ''Blaufelchen''. The two fish samples were examined electrophoretic ally for the enzyme products of 37 genetic loci. Blaufelchen and Gangf isch were genetically identical (Nei's unbiased genetic distance D = 0 .000) when all fish samples were included into the analysis. However, some genetic differentiation (D = 0.001) was evident after excluding t he fish whose data points on body weight versus egg weight overlapped. Additional enzyme systems or some other genetic methodology should be used to provide more information on the genetic status of the two whi tefish forms in Lake Constance.