Not to be cited without prior reference. to the authors International Council for the CM 1998/K:4 Exploration of the Sea Genetic differentiation of Polish sea trout, Salmo trutta m. trutta, populations based on RFLP analysis of PeR-amplified mtDNA segments by E. Wlodarczyk & R. Wenne Sea Fisheries Institute, ul. Kollataja I, 81-332 Gdynia, Poland *Fax: (+48 58) 620-28-31 E-mail:
[email protected] ABSTRACT Genetic differentiation among the populations of sea trout, Salrna trutta m. trutta, spawning in five Polish rivers has been investigated by RFLP ofPCR-amplified NADH-dehydrogenase 1 and 5/6 segments ofmtDNA. Total of 16 composite haplotypes were identified and the number of haplotypes per population ranged from 6 to 8. Three haplotypes were shared by all five populations and had similar frequencies ranging from 0.100 to 0.450. One haplotype was observed in 4 populations, two haplotypes in 3 populations and one haplotype was shared by 2 populations. Nine Tare.haplotypes were found in 4 populations, at frequencies ranging from 0.025 to 0.075. The highest number of rare haplotypes, three, was observed in the samples from the rivers Slupia and Pars((ta.. No rare haplotypes were detected in the river Wieprza. All populations were fixed at one morph for the ND-I segment digested with Hin!1. Key words: mtDNA, population genetics, RFLP, Salrna trutta m. trutta, sea trout. INTRODUCTION The sea trout ( Salrna trutta m. trutta) is an anadromous salmonid species of high commercial value, widely distributed in Europe. Its freshwater counterpart, the brown trout, has been extensively researched, and a number of studies have shown a strong population subdivision within the species (reviewed by Ferguson, 1989).