A century of genetic homogenization in Baltic salmon-evidence from archival DNA.
Proc Biol Sci
; 288(1949): 20203147, 2021 04 28.
Article
in En
| MEDLINE
| ID: mdl-33878928
ABSTRACT
Intra-species genetic homogenization arising from anthropogenic impacts is a major threat to biodiversity. However, few taxa have sufficient historical material to systematically quantify long-term genetic changes. Using archival DNA collected over approximately 100 years, we assessed spatio-temporal genetic change in Atlantic salmon populations across the Baltic Sea, an area heavily impacted by hydropower exploitation and associated with large-scale mitigation stocking. Analysis was carried out by screening 82 SNPs in 1680 individuals from 13 Swedish rivers. We found an overall decrease in genetic divergence and diminished isolation by distance among populations, strongly indicating genetic homogenization over the past century. We further observed an increase in genetic diversity within populations consistent with increased gene flow. The temporal genetic change was lower in larger wild populations than in smaller wild and hatchery-reared ones, indicating that larger populations have been able to support a high number of native spawners in relation to immigrants. Our results demonstrate that stocking practices of salmon in the Baltic Sea have led to the homogenization of populations over the last century, potentially compromising their ability to adapt to environmental change. Stocking of reared fish is common worldwide, and our study is a cautionary example of the potentially long-term negative effects of such activities.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Salmo salar
Limits:
Animals
/
Humans
Country/Region as subject:
Europa
Language:
En
Journal:
Proc Biol Sci
Journal subject:
BIOLOGIA
Year:
2021
Type:
Article
Affiliation country:
Sweden