0000000001315214
AUTHOR
Pekka Hyvärinen
showing 19 related works from this author
Life-history genotype explains variation in migration activity in Atlantic salmon (Salmo salar)
2021
AbstractOne of the most important life-history continuums is the fast–slow axis, where “fast” individuals mature earlier than “slow” individuals. “Fast” individuals are predicted to be more active than “slow” individuals; high activity is required to maintain a fast life-history strategy. Recent meta-analyses revealed mixed evidence for such integration. Here, we test whether known life-history genotypes differ in activity expression by using Atlantic salmon (Salmo salar) as a model. In salmon, variation in Vgll3, a transcription co-factor, explains ∼40% of variation in maturation timing. We predicted that the allele related to early maturation (vgll3*E) would be associated with increased a…
Opposing health effects of hybridization for conservation
2021
The continuing decline of many natural plant and animal populations emphasizes the importance of conservation strategies. Hybridization as a management tool has proven successful in introducing gene flow to small, inbred populations, but can be also associated with health risks. For example, hybridization can change susceptibility to infection in either direction due to heterosis (hybrid vigor) and outbreeding depression, but such health effects have rarely been considered in the genetic management of populations. Here, we investigated the effects of experimental outcrossing between the critically endangered Saimaa landlocked salmon (Salmo salar m. sebago) and the genetically more diverse A…
No evidence for an indirect benefit from female mate preference in Arctic charr Salvelinus alpinus, but female ornamentation decreases offspring viab…
2011
Female mate choice is considered an important evolutionary agent, but there has been an ongoing debate over the fitness consequences it produces, especially in species that have a resource-free mating system. We examined a potential fitness benefit resulting from the pre-spawning mate preference in Arctic charr Salvelinus alpinus, a salmonid fish with no parental care. The females were first allowed to discriminate behaviourally between two males presented to them in a free choice test. We then tested with controlled fertilizations whether the females would accrue indirect genetic benefits for their offspring, as measured by embryonic viability, if they had mated with the male they preferre…
Enriched rearing environment and wild genetic background can enhance survival and disease resistance of salmonid fishes during parasite epidemics
2015
Summary 1. The importance and volume of aquaculture is increasing world-wide. Rearing practices play a key role in determining growth rate, survival and disease resistance in aquaculture fishes. Recent evidence suggests that in comparison with a standard stimulus-poor rearing environment, an enriched or variable rearing environment has significant positive effects on several traits underlying growth and well-being of fish. However, the effect of enriched rearing on one of the most important threats for aquaculture development, occurrence of parasitic infections, remains unknown. 2. We used surveillance data of experimental salmonid populations of wild and hatchery origin under semi-natural …
Rearing background and exposure environment together explain higher survival of aquaculture fish during a bacterial outbreak
2019
1.Parasitic diseases represent one of the greatest challenges for aquaculture worldwide and there is an increasing emphasis on ecological solutions to prevent infections. One proposed solution is enriched rearing, where traditional stimulus‐poor rearing tanks are equipped with different types of structures to increase habitat complexity. Such spatial enrichment is known to increase survival of fish during parasite epidemics, but the underlying mechanisms are still unclear. 2.We studied whether enriched rearing affected infection of an important fish pathogen Flavobacterium columnare in young Atlantic salmon (Salmo salar) and sea‐migrating brown trout (Salmo trutta). First, we used natural b…
Cold water reduces the severity of parasite-inflicted damage : support for wintertime recuperation in aquatic hosts
2019
The reduction in host fitness caused by parasite infections (virulence) depends on infection intensity and the degree of damage caused per parasite. Environmental conditions can shape both virulence components, but in contrast to infection intensity, environmental impacts on per-parasite damage are poorly understood. Here, we studied the effect of ambient temperature on per-parasite damage, which is jointly determined by the ability of parasites to induce harm (per-parasite pathogenicity) and the ability of hosts to limit damage (tolerance). We experimentally exposed two salmonid species, Atlantic salmon (Salmo salar) and sea trout (Salmo trutta), to replicated genotypes of the eye fluke Di…
Negative associations between parasite avoidance, resistance and tolerance predict host health in salmonid fish populations
2020
Genetic variation in defence against parasite infections is fundamental for host–parasite evolution. The overall level of defence of a host individual or population includes mechanisms that reduce parasite exposure (avoidance), establishment (resistance) or pathogenicity (tolerance). However, how these traits operate and evolve in concert is not well understood. Here, we investigated genetic variation in and associations between avoidance, resistance and tolerance in a natural host–parasite system. Replicated populations of Atlantic salmon ( Salmo salar ) and sea trout (an anadromous form of brown trout, Salmo trutta ) were raised under common garden conditions and infected with the eye fl…
Host Developmental Stage Effects on Parasite Resistance and Tolerance.
2022
Hosts can defend themselves against parasites either by preventing or limiting infections (resistance) or by limiting parasite-induced damage (tolerance). However, it remains underexplored how these defense types vary over host development with shifting patterns of resource allocation priorities. Here, we studied the role played by developmental stage in resistance and tolerance in Atlantic salmon (Salmo salar). This anadromous fish has distinct life stages related to living in freshwater and seawater. We experimentally exposed 1-year-old salmon, either at the freshwater stage or at the stage transitioning to the marine phase, to the trematode Diplostomum pseudospathaceum. Using 56 pedigree…
Occurrence of Two-Year Cyclicity, “Saw-Blade Fluctuation”, in Vendace Populations in Finland
2021
The tendency towards two-year cyclicity is considered typical of many Fennoscandian vendace populations, especially in fluctuation of recruitment, based on time series of individual lakes. We used two robust indicators to identify and quantify two-year cycles in vendace population proxy time series at different life-stages — spawning stock biomass (SB), density of newly hatched larvae (LD) and recruitment (REC) — from 22 Finnish lakes. Then we applied Fisher’s meta-analytical test to assess the adequacy of the evidence to support the hypothesis that vendace population dynam-ics include two-year cyclicity. The results supported this hypothesis for RECbut not for SB or LD. Yet, the indicators…
Original data for manuscript: Quantity and Quality of Aquaculture Enrichments Influence Disease Epidemics and Provide Ecological Alternatives to Anti…
2021
The data processed and analyzed in this study are given in a single file: Karvonen et al. exposure data.xlsx. For detailed description of the material, methods and results of the study, see the article.
Supplementary tables and figures from Negative associations between parasite avoidance, resistance and tolerance predict host health in salmonid fish…
2020
Genetic variation in defence against parasite infections is fundamental for host–parasite evolution. The overall level of defence of a host individual or population includes mechanisms that reduce parasite exposure (avoidance), establishment (resistance) or pathogenicity (tolerance). However, how these traits operate and evolve in concert is not well understood. Here, we investigated genetic variation in and associations between avoidance, resistance and tolerance in a natural host–parasite system. Replicated populations of Atlantic salmon (Salmo salar) and sea trout (an anadromous form of brown trout, Salmo trutta) were raised under common garden conditions and infected with the eye fluke …
Quantity and Quality of Aquaculture Enrichments Influence Disease Epidemics and Provide Ecological Alternatives to Antibiotics
2021
Environmental heterogeneity is a central component influencing the virulence and epidemiology of infectious diseases. The number and distribution of susceptible hosts determines disease transmission opportunities, shifting the epidemiological threshold between the spread and fadeout of a disease. Similarly, the presence and diversity of other hosts, pathogens and environmental microbes, may inhibit or accelerate an epidemic. This has important applied implications in farming environments, where high numbers of susceptible hosts are maintained in conditions of minimal environmental heterogeneity. We investigated how the quantity and quality of aquaculture enrichments (few vs. many stones
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 …
Supplementary tables and figures from Negative associations between parasite avoidance, resistance and tolerance predict host health in salmonid fish…
2020
Genetic variation in defence against parasite infections is fundamental for host–parasite evolution. The overall level of defence of a host individual or population includes mechanisms that reduce parasite exposure (avoidance), establishment (resistance) or pathogenicity (tolerance). However, how these traits operate and evolve in concert is not well understood. Here, we investigated genetic variation in and associations between avoidance, resistance and tolerance in a natural host–parasite system. Replicated populations of Atlantic salmon (Salmo salar) and sea trout (an anadromous form of brown trout, Salmo trutta) were raised under common garden conditions and infected with the eye fluke …
Data from: Rearing background and exposure environment together explain higher survival of aquaculture fish during a bacterial outbreak
2019
1. Parasitic diseases represent one of the greatest challenges for aquaculture worldwide and there is an increasing emphasis on ecological solutions to prevent infections. One proposed solution is enriched rearing, where traditional stimulus-poor rearing tanks are equipped with different types of structures to increase habitat complexity. Such spatial enrichment is known to increase survival of fish during parasite epidemics, but the underlying mechanisms are still unclear. 2. We studied whether enriched rearing affected infection of an important fish pathogen Flavobacterium columnare in young Atlantic salmon (Salmo salar) and sea-migrating brown trout (Salmo trutta). First, we used natural…
Data from: Enriched rearing environment and wild genetic background can enhance survival and disease resistance of salmonid fishes during parasite ep…
2016
The importance and volume of aquaculture is increasing world-wide. Rearing practices play a key role in determining growth rate, survival and disease resistance in aquaculture fishes. Recent evidence suggests that in comparison with a standard stimulus-poor rearing environment, an enriched or variable rearing environment has significant positive effects on several traits underlying growth and well-being of fish. However, the effect of enriched rearing on one of the most important threats for aquaculture development, occurrence of parasitic infections, remains unknown. We used surveillance data of experimental salmonid populations of wild and hatchery origin under semi-natural parasite expos…
Supplemental Material for Lemopoulos et al., 2019
2019
Beagle file for the ANGSD pipeline. Genotype probabilities of 116 brown trout. 7520 SNPs are identified and mapped to corresponding location in the Atlantic salmon genome.
Management of human-induced contemporary evolution to maintain and restore genetic diversity in brown trout
2018
Maintaining genetic diversity and integrity of animal populations is a key challenge in conservation. While ecological population declines can be reversed, loss of genetic diversity and original trait distribution is often a one-way road. Migratory brown trout is critically endangered in Finland due to extensive modification of river ecosystems and unrestricted fishing on feeding areas. In addition to being too intense in general, fishing creates challenges by being selective for a number of traits in fish. We have shown that recreational angling, for example, is selective for certain personality traits and can cause inherited behavioural changes in the offspring of brown trout. Only a few …
Foraging, swimming performance and morphology of semi-wild and hatchery-reared landlocked salmon juveniles
2018
The Saimaa landlocked salmon (Salmo salar m. sebago) in Finland is a critically endangered ecomorph due to the historical damming of rivers. The morph has been dependent on stockings of hatchery-reared juveniles for more than 40 years. Recently, various efforts have been taken to restore some of the earlier reproduction areas to return the natural life cycle. However, as the population has been reared in hatcheries over many generations and as the released fish generally suffer high post-release mortality, it is crucial to know whether domestication has affected the population’s fitness-related traits and to assess how the developmental environment affects salmon’s phenotype. In the present…