Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster E29

Unveiling the genetic structure of brown trout populations in lake Þingvallavatn and the Ölfusá-Sog watershed

Höfundar / Authors: Marcos G. Lagunas (1), Magnús Jóhannsson (2), Benóný Jónsson (2), Arnar Pálsson (1), Zophonías O. Jónsson (1), Sigurður S. Snorrason (1)

Starfsvettvangur / Affiliations: 1. Háskóli Íslands, 2. Hafrannsóknastofnun

Kynnir / Presenter: Marcos G. Lagunas

Brown trout colonized lakes Úlfljótsvatn and Þingvallavatn soon after the ice-cap retreated from the area ca. 10,000 years ago. This trout became isolated from downstream populations early in post glacial history when two impassable waterfalls formed below Úlfljótsvatn. The population of lake Þingvallavatn went through a bottleneck between the 1960’s – 1990’s though it has recovered after several restoration attempts made between 1999 and 2005 using brood-stock from the Öxará river, the principal tributary of the lake.
Here we use ddRADseq data to assess the genetic structure of brown trout populations in lakes Þingvallavatn and Úlfljótsvatn. We also assess their relatedness to populations downstream of the impassable waterfalls and small stream populations in the Hengill mountain. The trout of lakes Þingvallavatn, Úlfljótsvatn and Öxará spawners are closely related (Fst values ranging between 0.013 and 0.037), and to some extent this may reflect the success of the restoration efforts. The differentiation pattern of the Hengill mountain streams reflects the connectivity of waterways. The streams in Miðdalur and Fremstidalur, which drain to Ölfusá, are closely related whereas the trout in Þverá, which drains to Þingvallavatn, although distinct, is most related to the Þingvallavatn/Úlfljótsvatn trout. The data suggest that there may be some downstream gene flow from the large populations in Þingvallavatn and Úlfljótsvatn.