Raine Kortet

University of Eastern Finland | UEF · Department of Environmental and Biological Sciences

A prerequisite of genetic rescue in endangered and genetically depauperate populations is to pre‐evaluate between possible pros and cons of hybridization for the life history and survival of the target population. We hybridized the critically endangered Saimaa landlocked salmon (Salmo salar m. sebago) with one of its geographically closest relative...

Plastic pollution has posed a significant environmental concern being widely spread in terrestrial and aquatic ecosystems. Nanoplastic particles (NPs: <1000 nm) have been drawing attention for their potential toxicological implications on organisms. Aquatic animals are increasingly exposed to NPs but their effects on many aquatic invertebrates rema...

Understanding the role of variation in host resistance and the multitude of transmission modes of parasites infecting hosts with complex behavioral interactions is essential for the control of emerging diseases. We used a discrete stage model to study the invasion dynamics of crayfish plague—an example of a detrimental disease—into a naïve host pop...

During the last two centuries, native noble crayfish (Astacus astacus) has been introduced and re-introduced into many waters in Finland, to widen the area of distribution, and to re-establish the collapsed populations. Recent studies have revealed narrowed genetic diversity in A. astacus populations, especially in North Europe, due to crayfish pla...

Freshwater mussels have a substantial role in aquatic ecosystem function and provide valuable ecosystem services, including water filtration, nutrient cycling, habitat creation and sediment stabilization. While they face population declines globally that can negatively affect an ecosystem's health, such as reducing the water quality and increasing...

The predicted global warming of surface waters can be challenging to aquatic ectotherms like freshwater mussels. Especially animals in northern temperate latitudes may face and physiologically acclimate to significant stress from seasonal temperature fluctuations. Na+/K+-ATPase enzyme is one of the key mechanisms that allow mussels to cope with cha...

Endangered wild fish populations are commonly supported by hatchery propagation. However, hatchery‐reared fish experience very different selective pressures compared to their wild counterparts, potentially causing genotype‐by‐environment interactions (G × E) in essential fitness traits. We experimentally studied early selection in a critically enda...

Anodonta anatina, a widely distributed Eurasian freshwater mussel, has dramatically declined and listed as endangered species in IUCN Red List in some parts of the Europe. To better understand its basic biology and possible sex-dependent effects of parasitism on reproduction, we investigated the reproductive traits, trematode parasitism and growth...

Despite the increasing concern about the harmful effects of micro- and nanoplastics (MNPs), there are no harmonized guidelines or protocols yet available for MNP ecotoxicity testing. Current ecotoxicity studies often use commercial spherical particles as models for MNPs, but in nature, MNPs occur in variable shapes, sizes and chemical compositions....

Threatened fish populations worldwide are relying on stock supplementation by hatchery‐reared fish. Although stocking with non‐native fish may lead to hybridization, thereby disrupting local adaptations, it could also improve the adaptive potential of small populations by increasing variability in essential behavioral traits. In this study, we cros...

We present an epidemiological model for the crayfish plague, a disease caused by an invasive oomycete Aphanomyces astaci, and its general susceptible freshwater crayfish host. The pathogen shows high virulence with resulting high mortality rates in freshwater crayfishes native to Europe, Asia, Australia, and South America. The crayfish plague occur...

“Advanced Materials” (AdMas) represent the next technology frontier. According to the European Union, AdMas are materials that feature a series of exceptional properties or functionalities compared to conventional materials. Considering the progress made in the design and application of AdMas, their adverse effects are still largely unknown whilst...

The smallest fraction of plastic pollution, submicron plastics (SMPs <1 μm) are expected to be ubiquitous in the environment. No information is available about SMPs in peatlands, which have a key role in sequestering carbon in terrestrial ecosystems. It is unknown how these plastic particles might behave and interact with (micro)organisms in these...

Sub-micron plastics (SMPs, size < 1 µm) are potentially taken up by plants. Serious concerns arise that how far SMPs can transfer from plants into food webs. Here, we show that lettuce takes up 250 nm gadolinium labelled polystyrene (PS) and polyvinyl chloride (PVC) SMPs from the soil. The polymer type influences the biodistribution of the particle...

Sub-micron plastics (SMPs, size < 1 μm) are potentially taken up by plants. Serious concerns arise that how far SMPs can transfer from plants into food webs. Here, we show that lettuce takes up 250 nm gadolinium labelled polystyrene (PS) and polyvinyl chloride (PVC) SMPs from the soil. The polymer type influences the biodistribution of the particle...

Competitive fishing is a global phenomenon covering thousands of fishing contests annually. We studied the experiential value of angling competitions from the participants’ point of view by using an online survey data among Finnish anglers who had been on an overnight angling competition trip within the last two years. The theory of consumption val...

Plastic pollution has been a growing environmental concern for decades, increasingly affecting both marine and freshwater ecosystems worldwide. Nano-sized plastic particles (NPs) potentially have various toxicological impacts on aquatic organisms and the ecosystem; however, less is known about their possible adverse effects on the reproductive biol...

Aquaculture is one of the most resource‐efficient and sustainable ways to produce animal protein. The Food and Agriculture Organization predicts that cultivated aquatic species will provide around 53% of the world's seafood supply by 2030. Further growth of intensive farmed aquatic species may be limited by a shortage of feed resources. The aquacul...

Similar to aquatic ectotherms, freshwater mussels are prone to the predicted global warming of surface waters. Sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA) has a crucial role in regulating intracellular Ca²⁺ concentration in muscle cells and potentially involved in setting thermal preferences and behaviors of animals. To this end, we examined t...

Plastics in the environment can be degraded to nanoscale plastic debris (NPD) with a size smaller than 1 µm. But it is unknown how the physicochemical properties of NPD influence their interaction with organisms and their toxicokinetics in organisms' bodies. This study uses the knowledge gained from investigating engineered polymeric nanomaterials...

Please cite this article as: F.A. Monikh, M. Durão, P.V. Kipriianov, et al., Chemical composition and particle size influence the toxicity of nanoscale plastic debris and their co-occurring benzo(α)pyrene in the model aquatic organisms Daphnia magna and Danio rerio, NANOIMPACT (2021), https://doi. Abstract Little is known about how particle chemica...

Exposure of aquatic organisms to micro- and nano-sized plastic debris in their environment has become an alarming concern. Besides having a number of potentially harmful impacts for individual organisms, plastic particles can also influence the phenotype and performance of their offspring. We tested whether the sperm pre-fertilization exposure to n...

Although the presence of small-scale plastics, including nanoscale plastic debris (NPD, size <1 μm), is expected in the environment, our understanding of their potential uptake and biodistribution in organisms is still limited. This mostly is because of the limitations in analytical techniques to characterize NPD in organisms' bodies. Moreover, it...

Cadmium (Cd) exposure can impair the traits of aquatic animals associated with reproduction. In natural lakes Cd is typically detected at concentrations below 0.001 mg l⁻¹. The authors investigated the impact of ultra‐acute Cd exposure on sperm motility in European whitefish (Coregonus lavaretus). They activated sperm with water containing various...

The landlocked salmon (Salmo salar m. sebago) endemic to Lake Saimaa, Finland, is critically endangered and severely threatened by low genetic diversity and inbreeding. To explore the possibility of increasing the genetic diversity of threatened salmon populations by controlled hybridization (genetic rescue), we studied sperm motility and offspring...

Certain spawning areas of the critically endangered Lake Saimaa landlocked Atlantic salmon (Salmo salar m. sebago) have been recently restored by excavator- and helicopter-scattered gravel, but the success of applied methodologies has remained open. Here, we monitored the spawning-related movements and redds occurrence of transported semi-wild and...

The deer ked (Lipoptena cervi) is a harmful ectoparasite that emerged in the reindeer herding area of Finland in 2006. To understand the current range and the intensity of infestations on its novel reindeer host, we studied deer ked pupae collected from reindeer and moose bedding sites and conducted a questionnaire survey among the managers of 18 r...

Enriched rearing has been demonstrated to shape the phenotype of hatchery-reared salmonids and improve their post-release survival in the wild, thus having an important applied value in conservation. However, it is unclear if rearing conditions or survival selection during the early life stages induce long-term fitness effects on adult phenotypes....

The presence of microplastics in aquatic ecosystems has recently received increased attention. Small plastic particles may resemble natural food items of larval fish and other aquatic organisms, and create strong selective pressures on the feeding traits in exposed populations. Here, we examined if larval ingestion of 90 μm polystyrene microspheres...

Several Finnish populations of salmonids have been maintained exclusively by stocking hatchery-reared fish for several generations, and it is crucial to know whether domestication has affected fitness-related traits and to assess how the developmental environment influences fish phenotypes. Here, we focused on Lake Saimaa landlocked salmon (Salmo s...

The taxonomic composition of microbial communities in animals varies among animal species, but the contribution of interspecific differences in filtering of the microbial pool by the animal host to this variation is uncertain. Here, we demonstrate significant interspecific variation in microbial community composition among laboratory-reared Drosoph...

Through the recent increases in abundance, pikeperch (Sander lucioperca) has not only become a valuable target for recreational and commercial fishing, but also the most important top predator in many lakes. Generally oligotrophic Lake Höytiäinen (283 km2) sustains one of the most economically valuable pikeperch stocks in Finland, and its annual fi...

The genus Aphanomyces (Oomycetes) comprises approximately 50 known species of water molds in three lineages. One of the most notorious is Aphanomyces astaci, the causative agent of crayfish plague. In this study, fresh isolates of Aphanomyces were collected from 20 live specimens of the signal crayfish Pacifastacus leniusculus (Dana, 1852) from Lak...

This article analyses the legal adaptive capacity for increasing sustainable fish aquaculture production in EU-Finland. Currently, fish aquaculture is driven by increasing global demand of fish, declining natural fisheries, food security and blue growth policies. At the same time, environmental policies such as the EU Water Framework Directive and...

Between-individual differences in personality and life-history traits can arise from both genetic and environmental factors, with the latter possibly reflecting contrasting individual experiences during ontogeny. It is yet unclear how the acoustic environment may affect the development of boldness and related life-history traits such as growth rate...

The elemental composition of organisms belongs to a suite of functional traits that may adaptively respond to fluctuating selection pressures. Life history theory predicts that predation risk and resource limitations impose selection pressures on organisms' developmental time and are further associated with variability in energetic and behavioral t...

Predator conditioning can be used to improve post‐release antipredator recognition of hatchery‐reared salmonids. However, possible negative stress‐related effects of prolonged predator conditioning on juvenile fish physiology are poorly understood. We studied the effects of prolonged (91 days) predator odour exposure on whole‐body cortisol level an...

Although hybridization between populations with low genetic diversity may induce heterosis, it can also lead to reduced fitness of hybrid offspring through outbreeding depression and loss of local adaptations. Using a half-sib mating design, we studied on brown trout (Salmo trutta) how hybridization of migratory hatchery-strain females with males f...

Aims of the study ▪ Enriched rearing environment can shape phenotypic traits and improve post-release survival of hatchery-reared salmonids. ▪ It is unclear whether rearing conditions during the early life stages impose long-term carryover effects for the adult phenotypes. ▪ Possible long-term effects of rearing practice on the primary and secondar...

Unintended domestication in hatchery broodstocks reflects a low success of supportive stocking programs. We crossbred adfluvial hatchery-stock brown trout (Salmo trutta) females with males from two non-native adfluvial hatchery strains and a wild but local resident strain to study survival, growth and behaviour of hybrid offspring alternatives. Exp...

The pace-of-life syndrome (POLS) concept predicts that individuals with high baseline metabolic rates demonstrate high boldness, aggressiveness, and activity, especially in food acquisition, with associated relatively greater energy requirements. In fishes, these behaviors may increase individual vulnerability to angling. To test the predictions of...

Sperm pre-fertilization environment has recently been suggested to mediate remarkable transgenerational consequences for offspring phenotype (transgenerational plasticity, TGB), but the adaptive significance of the process has remained unclear. Here, we studied the transgenerational effects of sperm pre-fertilization thermal environment in a cold-a...

The effect of temperature on physiology mediates many of the challenges that ectotherms face under climate change. Ectotherm immunity is thermally sensitive and, as such, environmental change is likely to have complex effects on survival, disease resistance and transmission. The effects of temperature on immunity will be particularly profound in wi...

The teleost genus Aphanius is currently composed of at least 32 species. Here, we present observational data from breeding experiments in which we studied two local populations of the Farsi tooth-carp A. farsicus in captivity. Combinations of parental fish from both populations were allowed to spawn in separate aquaria. The resulting offspring show...

Evidence suggests that brain serotonin (5-HT) is one of the central mediators of different types of animal personality. We tested this assumption in field crickets Gryllus integer using a selective serotonin reuptake inhibitor (SSRI). Crickets were selected for slow and rapid development and tested for their coping styles under non-stressful condit...

The oomycete Aphanomyces astaci , the causative agent of crayfish plague, is listed as one of the 100 worst invasive species in the world, destroying the native crayfish populations throughout Eurasia. The aim of this study was to examine the potential of selected mitochondrial (mt) genes to track the diversity of the crayfish plague pathogen A. as...

Hatchery-reared fish show high mortalities after release to the wild environment. Explanations for this include potentially predetermined genetics, behavioral, and physiological acclimation to fish farm environments, and increased vulnerability to predation and parasitism in the wild. We studied vulnerability to Diplostomum spp. parasites (load of...

The causes and consequences of among-individual variation and covariation in behaviours are of substantial interest to behavioural ecology, but the proximate mechanisms underpinning this (co) variation are still unclear. Previous research suggests metabolic rate as a potential proximate mechanism to explain behavioural covariation. We measured the...

The genus Aphanomyces (Saprolegniales, Oomycetes) includes species with a variety of ecologies from saprotrophs to plant and animal parasites. Two important species in this genus are A. astaci, the cause of crayfish plague and its close relative, A. invadans, which causes the epizootic ulcerative syndrome on fish. In this study, we have assembled a...

Among-individual differences in behavior are now a widely studied research focus within the field of behavioral ecology. Furthermore, elements of an animal’s internal state, such as energy or fat reserves, and infection status can have large impacts on behaviors. Despite this, we still know little regarding how state may affect the expression of be...

Predation can regulate populations and strongly affect invasion success of novel prey. The deer ked (Lipoptena cervi; Linnaeus 1758) is an invasive ectoparasite of cervids that spends a long period of its life cycle outside the host. Prior to this study, virtually nothing was known about natural summer time predation on the deer ked. We aimed to ev...

The offshore pelagic niche in Lake Kariba is mainly occupied by the Tanganyika sardine, Limnothrissa miodon, commonly called ‘kapenta’, which is a mainly zooplanktivorous clupeid fish. The population dynamics of kapenta fluctuate seasonally in synchrony with the physical processes that shape the trophic status of the lake. Diel feeding periodicity...

Theory-based predictions on asymmetries in animal contests have seldom been tested in situations where payoff asymmetries exist among contestants otherwise clearly matched for physical fighting capacity (i.e., resource holding potential, RHP). We examined the effects of food availability and predation risk on contest outcomes and the maintenance of...

Among the ecological factors acting on the evolution and expression of animal personalities and behavioral syndromes, parasitism has received comparatively little attention. However, infection and host behavior are often strongly intertwined, because host behavior can predict the risk of infection and can also be changed by an infection. We conduct...

Our understanding on the role of chemical signals in parasite-mediated sexual selection is still limited, and only some existing studies have focused on fish. Furthermore, published studies on the effect of parasite infection on behavioral sexual competition of the male hosts have yielded contradictory results. Here, we examined whether the infecti...

The influence of trophically transmitted parasite infection on fitness-related locomotor performance in fish as definite hosts has been studied relatively rarely and is thus mostly unknown. In this study, we examined the effect of body cavity dwelling nematode Philometra ovata on the swimming performance, fitness-related traits (male body quality)...

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 ef...

For many applications and ecological studies in which wild individuals are brought to laboratory it would be essential to know accurately how fast novel diet is reflected in composition of different tissues. To study the effects of two different diets on the stable isotope composition of freshwater crayfish muscle and hemolymph, we conducted a thre...

Abiotic and biotic factors determine success or failure of individual organisms, populations and species. The early life stages are often the most vulnerable to heavy mortality due to environmental conditions. The deer ked (Lipoptena cervi Linnaeus, 1758) is an invasive insect ectoparasite of cervids that spends an important period of the life cycl...

Immunity of parasites has been studied amazingly little, in spite of the fact that parasitic organisms, especially the arthropod parasites, need immunity to survive their own infections to successfully complete life cycles. Long-term effects of challenging environmental temperatures on immunity have remained unstudied in insects and parasites. Our...