Candidates for stream and lake restoration in Iceland
Jóhannes Guðbrandsson
28 November 12:00 Askja N-129
Peatland restoration has been highlighted in Iceland as an important climate action as raising groundwater levels helps stop the release of carbon from drained soil.
We explored the potential for stream and lake restoration in Hraunhreppur in the Mýrar, with a special focus on trout spawning areas in streams and migration routes for trout and eel.
#brownTrout #restoration #Fridaybiology
Limnology projects presented
4 field sites,
4 groups,
4 projects
great work and great fun
#brownTrout #eel #flounder #AtlanticSalmon #limnology #Iceland
100 downloads of my 'Genetic structure and relatedness of brown trout (Salmo trutta) populations in the drainage basin of the Ölfusá river, South-Western Iceland' article published in #OpenAccess journal @PeerJLife
Status of salmonid stocks in Iceland
Summary of salmon trout and charr fishing and prospects
Picture from Westfjords
Dynjandi river runninn into Arnarfjörður
#salmonid #atlanticSalmon #browntrout #ArcticCharr #Dynjandi
https://www.hafogvatn.is/is/midlun/frettir-og-tilkynningar/upptaktur-ad-veidisumrinu-2025
Tröllafoss spring 2021
Leirvogsá river runs from Leirvogur up to Lake Leirvogsvatn
Leir-vogur translates to clay-cove
Above the waterfall is the lake, and in it the brown trout with lowest level of genetic variation
#ecology #browntrout #popgen #colonization
#waterfall #Tröllafoss #salmonid #iceland #Thingvallavatn #Leirvogsvatn
https://peerj.com/articles/15985/
Background Lake Þingvallavatn in Iceland, a part of the river Ölfusá drainage basin, was presumably populated by brown trout soon after it formed at the end of the last Ice Age. The genetic relatedness of the brown trout in Þingvallavatn to other populations in the Ölfusá drainage basin is unknown. After the building of a dam at the outlet of the lake in 1959 brown trout catches declined, though numbers have now increased. The aim of this study was to assess effects of geographic isolation and potential downstream gene flow on the genetic structure and diversity in brown trout sampled in several locations in the western side of the watershed of River Ölfusá. We hypothesized that brown trout in Lake Þingvallavatn constituted several local spawning populations connected by occasional gene flow before the damming of the lake. We also estimated the effective population size (NE) of some of these populations and tested for signs of a recent population bottleneck in Lake Þingvallavatn. Methods We sampled brown trout inhabiting four lakes and 12 rivers within and near the watershed of River Ölfusá by means of electro- and net- fishing. After stringent data filtering, 2,597 polymorphic loci obtained from ddRADseq data from 317 individuals were ascertained as putative neutral markers. Results Overall, the genetic relatedness of brown trout in the Ölfusá watershed reflected the connectivity and topography of the waterways. Ancestry proportion analyses and a phylogenetic tree revealed seven distinct clusters, some of which corresponded to small populations with reduced genetic diversity. There was no evidence of downstream gene flow from Lake Þingvallavatn, although gene flow was observed from much smaller mountain populations. Most locations showed low NE values (i.e., ~14.6 on average) while the putative anadromous trout from River Sog and the spawning population from River Öxará, that flows into Lake Þingvallavatn, showed notably higher NE values (i.e., 71.2 and 56.5, respectively). No signals of recent population bottlenecks were detected in the brown trout of Lake Þingvallavatn. Discussion This is the first time that the genetic structure and diversity of brown trout in the watershed of River Ölfusá have been assessed. Our results point towards the presence of a metapopulation in the watershed of Lake Þingvallavatn, which has been influenced by restoration efforts and is now dominated by a genetic component originated in River Öxará. Many of the locations studied represent different populations. Those that are isolated in headwater streams and lakes are genetically distinct presenting low genetic diversity, yet they can be important in increasing the genetic variation in downstream populations. These populations should be considered for conservation and direct management.
Antti Eloranta
Aquatic ecologist studying fish populations and lake food webs, with a primary focus on the trophic ecology of salmonids in subarctic lakes.
#Foodwebs #lakes #fennoscandian #fish #Arctic #subarctic #BrownTrout #ArcticCharr #stickleback #ecology
Welcome to my homepage! I am an aquatic ecologist studying fish populations and lake food webs, with a primary focus on the trophic ecology of salmonids in subarctic lakes. I have used stable isotope analyses and space-for-time modelling to study how e.g. lake morphometry, productivity, climatic
charrvein
Charrvein
The FSBI
Stéphane ALTITUDE PÊCHE