Search results for "vaellus"

Migration strategies of brown trout (Salmo trutta) in a subarctic river system as revealed by stable isotope analysis

2018

We estimated the proportions of anadromous and freshwater‐resident brown trout (Salmo trutta) in different parts of the subarctic River Näätämöjoki/Neidenelva system (Finland and Norway) using carbon, nitrogen and hydrogen stable isotope analyses of archived scales as identifiers of migration strategy. Our results showed that carbon stable isotope values were the best predictor of migration strategy. Most individuals fell into two clearly distinct groups representing anadromous (47%) or freshwater‐resident (42%) individuals, but some fish had intermediate carbon values suggesting repeated movement between freshwater and the sea. The proportion of anadromous individuals decreased steadily wi…

Comparison of Migratory and Resident Populations of Brown Trout Reveals Candidate Genes for Migration Tendency

2018

Abstract Candidate genes associated with migration have been identified in multiple taxa: including salmonids, many of whom perform migrations requiring a series of physiological changes associated with the freshwater–saltwater transition. We screened over 5,500 SNPs for signatures of selection related to migratory behavior of brown trout Salmo trutta by focusing on ten differentially migrating freshwater populations from two watersheds (the Koutajoki and the Oulujoki). We found eight outlier SNPs potentially associated with migratory versus resident life history using multiple (≥3) outlier detection approaches. Comparison of three migratory versus resident population pairs in the Koutajoki…

Atlantic salmon survival at sea: temporal changes that lack regional synchrony

2022

Spatial and temporal synchrony in abundance or survival trends can be indicative of whether populations are affected by common environmental drivers. In Atlantic salmon (Salmo salar L.), return rates to natal rivers have generally been assumed to be affected primarily by shared oceanic conditions, leading to spatially synchronous trends in mortality. Here, we investigated the existence of parallel trends in salmon sea survival, using data on migrating smolts and returning adults from seven Canadian populations presumed to share feeding grounds. We analysed sea survival, using a Bayesian change-point model capable of detecting non-stationarity in time series data. Our results indicate that w…

Environmentally driven changes in Baltic salmon oxidative status during marine migration.

2020

The fitness and recruitment of fish stocks can be markedly affected by environmental disturbances including global warming, eutrophication and contamination. Understanding the effects of environmental stressors on salmon physiology during marine residence is of a global concern as marine survival has decreased. We present a unique combination of physiological responses - antioxidant defence and oxidative damage biomarkers, stable isotopes and contaminant exposure biomarkers - measured from adult Atlantic salmon (Salmo salar) collected at the Baltic Sea and studied in relation to environmental variables and fitness estimates. The results demonstrate that feeding populations of salmon display…

Migratory connectivity amongst Baltic Sea salmon

2014

Association Mapping Based on a Common-Garden Migration Experiment Reveals Candidate Genes for Migration Tendency in Brown Trout

2019

A better understanding of the environmental and genetic contribution to migratory behavior and the evolution of traits linked to migration is crucial for fish conservation and fisheries management. Up to date, a few genes with unequivocal influence on the adoption of alternative migration strategies have been identified in salmonids. Here, we used a common garden set-up to measure individual migration distances of generally highly polymorphic brown trout Salmo trutta from two populations. Fish from the assumedly resident population showed clearly shorter migration distances than the fish from the assumed migratory population at the ages of 2 and 3 years. By using two alternative analytical …

Vuoristovaelluksen vaikutus autonomisen hermoston toimintaan : adaptaation etenemisen seuranta sykevälivaihtelumuuttujien ja satelliittipaikannuksen …

2014

Vuoristoympäristö on ihmisen fysiologialle yksi epäsuosiollisimmista olosuhteista maapallolla. Vuoristo-olosuhteiden fysikaaliset ominaispiirteet, hypobaarinen hypoksia sekä kylmä ilmasto, asettavat monenlaisia vaatimuksia ihmisen elimistön toimintakyvyn ylläpitämiseksi. Akuutti vuoristotauti ilmenee henkilöillä, joilla vuoristoon sopeutuminen ja kompensoivat toimet eivät ole edistyneet onnistuneesti. Hoitamattomana tila voi edetä hengenvaaralliseen aivo- tai keuhkoödeemaan. Viimeaikaisissa tutkimuksissa on raportoitu lupaavia tuloksia yksilöiden välisistä keskushermoston sopeutumismallieroista vuoristotaudin diagnosoinnissa. Tämän tutkimuksen tarkoituksena oli selvittää löytyykö ortostaatt…

Investigating different migration patterns of Salmo trutta (L.) in the Teno river system using stable isotope analyses

2009

Halti-projekti 2004 : elämyksiä ja kokemuksia erävaelluksella

2005

Itämeren harmaahylkeiden (Halichoerus grypus) liikkumisen selvittäminen vakaiden isotooppien menetelmällä

2016

Harmaahylkeiden (Halichoerus crypus) määrän lisääntyminen on aiheuttanut viime vuosikymmeninä voimakkaita ristiriitoja kalastuselinkeinon kanssa koko Itämeren alueella. Harmaahylkeiden elinpiirejä Itämerellä on tutkittu paljon, mutta niiden pidemmistä vaelluksista tarvitaan vielä lisätietoa esimerkiksi kannanhoidon suunnittelua varten. Tämän tutkimuksen tarkoituksena oli lisätä tietoa harmaahylkeiden vaelluksista Itämerellä ja tarkastella vakaiden isotooppien menetelmän soveltuvuutta harmaahylkeiden eri merialueiden välisen liikkumisen selvittämiseen. Lisäksi tässä työssä tutkittiin harmaahylkeen sukupuolen, iän, pyyntivuodenajan ja pyydystyspaikan vaikutusta vaeltaneiden yksilöiden määrään…