Genetic differentiation in
hatchery and wild sea trout (Salmo trutta) in the Southern Baltic at
microsatellite loci
A. Was, R. Wenne-2002
Aquaculture, 204(3-4): 493-506
Abstract:
Sea trout (Salmo trutta) is a commercially
important anadromous salmonid species in the Baltic Sea. Sea trout return
for spawning to natal rivers (homing). The number of wild smolts migrating
to the sea from rivers in Poland decreased from about 1.5 million ca. 70
years ago to less than 100,000 in recent years. This decrease has been
caused by deterioration of the environment, regulation of rivers and dam
constructions. Stocking activities have been undertaken to enhance naturally
occurring populations. Over 1.5 million smolts are released to Polish rivers
each year. Variation at microsatellite loci was used to study genetic
differentiation between hatchery-produced smolts and wild-caught spawners
returning to rivers. Polymorphism at five loci, Ssa197, Ssa171,
Ssa85, Str15 and Str73, was assessed. The number of
alleles in hatchery populations was lower, whereas heterozygosity levels
were similar across all populations. The genetic composition of adult fish
returning to the Vistula River in summer was similar to that of the Rega
River population. Populations of hatchery-produced smolts originally derived
from Vistula River sea trout were also similar to the Rega River sea trout
population. The original Vistula River population may still be represented
by some winter spawners and by populations in Drweca or tributaries above
the Włocławek dam.
(Sea Fisheries Institute, Kollataja 1, 81-332 Gdynia,
Poland)