ALLOZYME VARIABILITY OF BROWN TROUT (SALMO-TRUTTA L) POPULATIONS ACROSS THE RHENANIAN-DANUBIAN WATERSHED IN SOUTHWEST GERMANY

Using horizontal agarose thin layer gel electrophoresis, 35 allozyme l oci were screened in 233 brown trout (Salmo trutta L.) from 11 populat ions in southwest Germany across the Rhenanian-Danubian watershed. Pol ymorphism was found at 10 loci, with stocked populations exhibiting si gnificantly increased polymorphism compared with unmanaged stocks (P=0 .219 vs. P=0.132). Standard genetic distances between populations from different brooks averaged at D=0.01. Of the total gene diversity of G (ST)=0.198, only a negligible amount partitioned between Rhenanian and Danubian drainages (G(GT)=0.010). One biallelic locus, LDH-5, indica ted river-specific allele frequencies, with the allele LDH-5105 being markedly more frequent within the Danubian drainage system. In contra st, LDH-5100 was close to fixation in the Rhenanian populations. This locus suggests a phylogeographical relationship of Danubian trout fro m southwest Germany with brown trout from southeastern Europe rather t han with conspecifics of adjacent Rhenanian origin.