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• Velle, Gaute; Bryn, Anders; Kausrud, Kyrre; Kirkendall, Lawrence R.; Malmstrøm, Martin & Sandercock, Brett Kevin [Show all 12 contributors for this article] (2026). Cumulative impacts from co-occurring non-native species. VKM Report. 2026(03), p. 1–80. Full text in Research Archive Show summary

  This report examines how co-occurring non-native species can interact to create cumulative impacts on ecosystems. Non-native species may interact in additive, antagonistic, or synergistic ways. Through literature review, we found theoretical foundations and empirical examples showing that such interactions often occur. Synergistic interactions are of particular concern. Certain ecosystems appear particularly susceptible, including agricultural landscapes, urban environments, riparian systems, shipping-influenced marine areas, and islands with naïve fauna. We conclude that cumulative effects are ecologically important, and that it would be beneficial to incorporate multispecies interactions into risk assessments of non-native species in Norway.

• Kirkendall, Lawrence R.; Flø, Daniel; Malmstrøm, Martin; Nielsen, Anders; Berg, Paul Ragnar & Bryn, Anders [Show all 13 contributors for this article] (2025). Assessment of the risks of negative impact on biodiversity in Norway from import and keeping of the Turkestan cockroach (Periplaneta lateralis). Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2025(07), p. 1–45. doi: https:/vkm.no/english/riskassessments/allpublications/lowriskassociatedwiththeimportandkeepingofturkestancockroach.4.78f38f6a1972b767482b0170.html. Full text in Research Archive Show summary

  VKM has assessed the potential risk to Norwegian biodiversity associated with the import of the Turkestan cockroach, Periplaneta lateralis, as live food for hobby animals. Populations of the cockroach are nearly always found in or near buildings, and non-native populations have never been observed in natural environments. No previous observations of P. lateralis have been reported for Norway and it is very unlikely the species will be able to establish and spread into Norwegian nature due to the low winter temperatures and short summers. Furthermore, VKM find that there is low risk associated with the potential effects on biodiversity, if it against all odds, were to establish in Norway. Therefore, VKM concludes that there is low risk associated with import and keeping of P. lateralis in relation to its potential negative effect on Norwegian biodiversity.

• Velle, Gaute; Thorstad, Eva Bonsak; Garseth, Åse Helen; Gjøen, Tor; Gulla, Snorre & Lo, Håvard [Show all 8 contributors for this article] (2025). Balancing the restoration of a native fish and the risks of hitchhiking invasive species. Management of Biological Invasions. ISSN 1989-8649. 16(1), p. 247–276. doi: 10.3391/MBI.2025.16.1.15. Full text in Research Archive Show summary

  Reintroducing a species to an area where it is locally extinct may contribute to reestablishing the ecosystem. However, we show that such reintroductions can pose a risk to biodiversity by introducing hitchhiking invasive organisms together with the donor population. This risk was caused by more severe impacts of invasive organisms in the habitat of the donor population than the receiving environment. The freshwater resident Atlantic salmon (Salmo salar) in Sweden’s River Klarälven perform feeding migrations to Lake Vänern. The upper part of the watershed, in Norway, lost its salmon population due to hydropower development that obstructed upstream migration. We conducted a risk assessment of the potential impacts on native ecosystems from invasive organisms associated with reintroducing Atlantic salmon into the Norwegian part of the watershed by importing adult salmon spawners. This assessment is crucial due to differences in the development of invasive organisms in the Swedish and Norwegian parts of the watershed. The risk of impacts was evaluated for invasive species, parasites, bacterial pathogens, and viruses that are present or likely present in the lower part of the watershed, or at risk of being introduced. We found a high risk of negative impacts associated with the parasite Gyrodactylus salaris, viral hemorrhagic septicemia virus (VHSV), Aphanomyces astaci causing crayfish plague, Renibacterium salmoninarum causing bacterial kidney disease, and Tetracapsuloides bryosalmonae causing proliferative kidney disease. In addition, 20 invasive species and pathogens were associated with a medium risk and three with a low risk. The case study contributes to a deeper understanding of how reestablishing locally extinct or diminished species can influence biodiversity conservation efforts and the health of aquatic ecosystems, underlining the importance of comprehensive planning in restoration projects. We highlight the importance of risk assessment of invasive species when considering the reintroduction of native species or dam removal. environmental risk assessment, non-native species, species reintroduction, pathogens, landlocked Atlantic salmon, biological conservation, dam removal

• Hindar, Kjetil; Bodin, Johanna Eva; Dalen, Knut Tomas; Duale, Nur; Garseth, Åse Helen & Malmstrøm, Martin [Show all 14 contributors for this article] (2025). Overview of methods for production of sterile salmonids, their applicability in aquaculture and possible implications to wild salmon populations and biodiversity in Norway. VKM Report. 2025(02), p. 1–92. doi: https:/vkm.no/risikovurderinger/allevurderinger/steriloppdrettsfiskeffekterpabiologiskmangfold.4.6b6641cb18a179b6780ab2db.html. Full text in Research Archive Show summary

  VKM has assessed the positive and negative effects on biodiversity were sterile salmon to be used in Norwegian aquaculture. Triploidisation is assessed as the most effective method for sterilising fish, but it can affect the welfare and health of the fish. Several other techniques for producing sterile salmon are being tested, but it is too early to determine whether they can be used in large-scale farming. This is the key message in a knowledge summary VKM has prepared for the Norwegian Environment Agency. Background Escaped farmed salmon poses a major threat to wild salmon in Norway. hey can interbreed with wild salmon, genetically alter them, and make the populations less adaptable and more vulnerable to disease and environmental changes. A possible solution to the problem may be to use sterile salmon in farming. To date, only triploidisation has been tested. Newly fertilised eggs are given a hydrostatic pressure shock, thereby retaining an extra set of chromosomes which render the fish sterile. This method is currently the only one tested on a large scale. Triploidisation is effective but can also pose health and welfare challenges to fish. Methods VKM has reviewed available scientific literature regarding methods that can be used to produce sterile salmon. VKM has assessed whether these methods work as well, or better, than triploidy and whether they are likely to have fewer negative effects on fish welfare. Assessments have also been made of whether farmed fish treated with other sterilisation methods pose a greater or lesser threat to wild salmon than traditional farmed salmon. VKM has looked at the possibilities for further development of the triploidisation technique and has also assessed various methods currently being tested for producing sterile fish. Some of these are still at the laboratory-testing stage, while others are approaching trials with release into sea-pens. VKM has grouped the different methods based on whether they cause permanent changes in the genome (so-called "knock-out" of important genes) or whether the changes only result in temporary blocking or downregulation of gene expression (so-called "knock-down"). Results VKM concludes that triploidisation remains the most effective method and that there are possibilities to further develop this methodology through targeted breeding and adjustments in how the fish are kept. These measures can potentially solve the challenges for fish health and welfare. Using pure triploid female lines can also reduce some of the other challenges by preventing spawning interactions in rivers and reducing disease transmission to wild salmon. Alternative sterilisation methods, such as gene editing, vaccination, and temporary downregulation of proteins for gonad development using antisense oligomers and egg immersion, are promising but still under development. VKM assesses that methods causing permanent changes in the genome of diploid fish have a higher inherent risk than methods that only affect gene expression. Hope in egg-bathing Perhaps the most promising technique for safe production of sterile salmon is to add synthetic oligonucleotides to the eggs at an early stage, thereby preventing germ cell development without causing any inheritable changes. Such oligonucleotides can be injected into the eggs or absorbed by the eggs through bathing (immersion) in a special solution. "Especially the method involving targeted 'tools,' such as oligonucleotides that prevent germ cell development and can be added to the eggs in a water bath, seems promising," says Johanna Bodin, member of the Panel for Genetically Modified organisms and spokesperson for the report. (...)

• Velle, Gaute; Berg, Paul Ragnar; Järnegren, Johanna; Malmstrøm, Martin; Bryn, Anders & Hindar, Kjetil [Show all 12 contributors for this article] (2024). Assessment of risks posed by the import of live crabs intended for human consumption. Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2024(09), p. 1–99. Full text in Research Archive Show summary

  The Norwegian Environment Agency asked VKM to evaluate the risks to biodiversity associated with the importation of eight species of live crabs intended for human consumption. Background Invasive crab species represent a significant threat to biodiversity globally due to their omnivory, adaptability to diverse habitats, high reproductive output, and aggressive behaviour. The Norwegian Environment Agency has raised concerns about the potential ecological risks posed by the import of live crabs to Norway intended for human consumption. This report provides a risk assessment of eight species of crabs that could have negative effects on native biodiversity. The species include Chinese mitten crab (Eriocheir sinensis), Japanese mitten crab (E. japonica), blue crab (Callinectes sapidus), Atlantic rock crab (Cancer irroratus), Asian paddle crab (Charybdis japonica), common moon crab (Matuta victor), African blue swimming crab (Portunus segnis), and Harris mud crab (Rhithropanopeus harrisii). Three of the assessed species were recently confiscated at Norway's border. This suggests a market demand that could increase the frequency of introductions to Norway. Methods VKM established a working group with expertise in invertebrates and risk assessment. The group searched scientific literature for information on the taxonomy, natural history, invasiveness, and ecology for each crab species. If scientific literature was lacking, supplemental google searches allowed for a broader understanding of species with limited research or on the use and transportation of live crabs as food. The assessment utilized the EICAT framework (Environmental Impact Classification for Alien Taxa) to identify potential mechanisms by which each species could harm native biodiversity, should imported specimens become established in Norwegian nature. Key mechanisms include competition, predation, pathogen transmission, and hybridization. The relevant mechanisms were analysed for each species by rating the potential magnitude of impact on biodiversity from minimal to massive. The likelihood of each impact was assessed from very unlikely to very likely. A combination of magnitude of impact and likelihood resulted in final risk levels ranging from low and medium to possibly high and high. Confidence levels for each assessment were also categorized as low, medium, or high based on expert opinion. Results The potential hazards evaluated under the EICAT framework include competition, predation, and transmission of disease for all species, grazing for four species and structural impacts on the ecosystem for three species. The conditions required for crabs imported live for human consumption to reach a natural ecosystem in Norway include a commercial demand for crabs, survival during transport and handling, and the possibility of release or escape. If these conditions for reaching a natural ecosystem are met, the species must then be capable of establishment in the new ecosystem. There are several examples of species imported live for human consumption becoming established in the wild, most likely due to intentional release. The risk assessments indicate varied levels of risk across the five hazards. Competition from E. sinensis or E. japonica was assessed to pose a high risk, while competition from C. sapidus, C. irroratus, M. victor, P. segnis, or R. harrisii was assessed to pose a medium risk. Predation by E. sinensis or E. japonica was assessed to pose a high risk and predation from R. harrisii, C. sapidus, C. irroratus, M. victor, or P. segnis was assessed to pose a medium risk. Transmission of disease from either E. sinensis or E. japonica was assessed to pose a high risk, while there was a possibly high risk of disease transmission from C. irroratus. The diseases of highest concern include the crayfish plague (Aphanomyces astaci) and gaffkaemia (Aerococcus viridans var. homari). Finally, there was a moderate risk of ......

• Kirkendall, Lawrence Richard; Kausrud, Kyrre Linné; Malmstrøm, Martin; Berg, Paul Ragnar; Bryn, Anders & Hindar, Kjetil [Show all 12 contributors for this article] (2024). Assessment of risks posed by import of live medicinal leeches to biodiversity in Norway. Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2024(07), p. 1–66. Full text in Research Archive Show summary

  The Norwegian Environment Agency has asked VKM to evaluate the risks to biodiversity associated with the import of two species of leeches to Norway, Hirudo medicinalis and H. verbana (so-called medicinal leeches). In addition, they ask that the project group suggest mitigating measures that could reduce any potential risks, should import of the two species be granted. Background Bloodsucking leeches have been employed by humans for millennia. The two species Hirudo medicinalis and H. verbana have dominated the trade in medicinal leeches in Europe. Overcollection combined with loss or degradation of freshwater habitats led to a precipitous decline in European populations by the 1800s and led to a corresponding increase in imports from Turkey, North Africa, Russia and the Middle East. By the turn of the 19th century, the demand for live leeches in Europe had tapered off as contemporary medicine developed, only to have a small resurgence over the last decades as live leeches became recognized as useful for a variety of medical and cosmetic procedures, and to be the source of bioactive molecules of interest to medical researchers. As traditional medicine in Asia also uses a variety of leech products, there is a robust global market for live leeches and leech derivatives that is being met mostly by leech aquaculture, where the live leech trade seems dominated by H. verbana. There is increasing interest in commercializing production and sale of three similar leech species, H. orientalis from Central Asia, H. sulukii from a small region in Turkey, and H. troctina from North Africa. Hirudo medicinalis has been used medicinally in Norway since at least the Middle Ages when they were used by barber-surgeons for bloodletting. Leeches have been dispensed by apothecaries up until the end of the 1950s. Phylogeographic studies have treated the species as native to southern Norway and the Norwegian Biodiversity Information Centre has numerous records of H. medicinalis, with recent records primarily from the eastern coast of southern Norway. The Norwegian Red List for Species categorizes H. medicinalis as being of Least Concern in Norway. Hirudo verbana naturally occurs in southern Europe and has not been observed in Scandinavia so far (see map in Figure 2). Methods for the risk assessment VKM established a small working group with expertise in invertebrates and risk assessment. Our group combed the scientific literature and relevant websites for information on the taxonomy, natural history, ecology, and medical uses of medicinal leeches broadly and H. medicinalis and H. verbana specifically. The project group contacted major leech providers in Europe and North America to learn more about leech production and sale. Using the EICAT (Environmental Impact Classification for Alien Taxa) system developed by the IUCN, The project group identified those mechanisms (“hazards”) through which these two species could affect native biodiversity in Norway should imported specimens become established in Norwegian nature, and characterized the risk related to each of these hazards. The project group then conducted a semi-quantitative risk assessment for the species according to four categories: Low, Medium, Possibly high, and High risk. Hazards: how likely, how impactful, and overall risks In our report, VKM regard H. medicinalis as a native species, since it is so treated by Hirudo experts and is widespread in Norway. The project group regards H. verbana as non-native to Norway. The potential hazards from the EICAT system that could be associated with introducing one or both species include predation and parasitism, competition, disease transmission, and hybridization. ................................ .................................... Conclusions VKM concludes that the overall risk to biodiversity in Norway from importing live H. medicinalis and H. verbana is low.

• Järnegren, Johanna; Gulliksen, Bjørn; Husa, Vivian; Malmstrøm, Martin; Oug, Eivind & Berg, Paul Ragnar [Show all 16 contributors for this article] (2023). Assessment of risk and risk-reducing measures related to the introduction and dispersal of the invasive alien carpet tunicate Didemnum vexillum in Norway. VKM Report. 2023(7), p. 1–124. Full text in Research Archive Show summary

  Didemnum vexillum is colonial sea squirt, a marine species which originates from the northwest Pacific; it was first recorded in Norway in November 2020. Didemnum vexillum is an alien species, meaning that it is a species that has been transferred from its original region to other regions of the world through human activity, and it had not previously been recorded in Norwegian waters. The species is regarded as having great invasive potential and having strong negative ecological effects on biodiversity. It is also considered to pose a risk to marine industries such as shipping and aquaculture, with possible major negative economic impacts.

• Nilsen, Erlend Birkeland; Braastad, Bjarne Olai; Dale, Svein; Dervo, Børre Kind; Kausrud, Kyrre Linné & Kirkendall, Lawrence Richard [Show all 18 contributors for this article] (2023). Assessment of the risks posed by domestic cats (Felis catus) to biodiversity and animal welfare in Norway. Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2023(23), p. 1–228. Full text in Research Archive Show summary

  VKM has evaluated to what extent keeping of cats pose a risk to biodiversity in Norway. Risks were assessed separately for threats to biodiversity from direct predation, indirect (non-lethal) effects, competition with other wildlife and spread of infectious organisms. VKM also assessed the risk of reduced animal welfare related to the keeping of domestic cats, both for the cats and their prey. In addition, VKM has assessed a range of risk-reducing measures aimed at minimizing the risk for negative impacts on biodiversity and animal welfare. Overall, VKM find that the risk of negative impact on vulnerable birds and red-listed mammalian species are high under certain conditions. VKM also find that there is a considerable risk associated with increased spread of infectious organisms from cats to wildlife and other domestic species. Some of these infectious organisms may also infect humans. With respect to mitigation measures, VKM concludes that measures focused on limiting cats’ access to prey populations are likely to yield the most positive outcomes in terms of mitigating the adverse impact on biodiversity.

• Kirkendall, Lawrence Richard; Bryn, Anders; Flø, Daniel; Malmstrøm, Martin; Velle, Gaute & Berg, Paul Ragnar [Show all 12 contributors for this article] (2023). Assessment of the risk to Norwegian biodiversity from private import and keeping of Northern Cardinal. Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2023(18), p. 1–87. Full text in Research Archive Show summary

  VKM has evaluated the risk to biodiversity from allowing private import and keeping of the Northern Cardinal as a caged bird in Norway, for birds acquired through the bird trade. VKM has reviewed the invasion ecology of non-native birds in general and of the Northern Cardinal specifically. The assessment includes evaluation of various mechanisms that invasive birds generally have a negative impact through, and includes competition, hybridization, spread of pathogens and interactions with other alien species in Norway. VKM has also evaluated two different scenarios establishment and how climate change can influence both the negative impact and the likelihood of establishment. Overall, VKM finds that there is low risk in regards negative effects on biodiversity in Norway in regard to import and keeping of the Northern Cardinal.

• Hindar, Kjetil; Bodin, Johanna Eva; Duale, Nur; Jevnaker, Anne-Marthe Ganes; Garseth, Åse Helen & Malmstrøm, Martin [Show all 15 contributors for this article] (2023). Environmental risk assessment of genetically modified sterile VIRGIN® Atlantic salmon for use in research trials in aquaculture sea-cages. VKM Report. 2023:20, p. 1–94. Full text in Research Archive Show summary

  One of the substantial environmental challenges posed by the aquaculture industry is the escape of farmed Atlantic salmon (Salmo salar), which can mate with wild Atlantic salmon and alter the genetic composition of the wild populations. One potential solution to mitigate this issue is the cultivation of sterile salmon in aquaculture. Atlantic salmon can be made sterile by pressure or temperature treatment of newly fertilized eggs to produce triploids, which are functionally sterile due to their unpaired chromosomes. However, these triploids often perform poorly on commercial fish farms and the production of triploid salmon in Norway is put on hold due to welfare issues of the fish.

• Piot, Niels; Schweiger, Oliver; Meeus, Ivan; Yañez, Orlando; Straub, Lars & Villamar-Bouza, Laura [Show all 26 contributors for this article] (2022). Honey bees and climate explain viral prevalence in wild bee communities on a continental scale. Scientific Reports. 12. doi: 10.1038/s41598-022-05603-2. Full text in Research Archive Show summary

  Viruses are omnipresent, yet the knowledge on drivers of viral prevalence in wild host populations is often limited. Biotic factors, such as sympatric managed host species, as well as abiotic factors, such as climatic variables, are likely to impact viral prevalence. Managed and wild bees, which harbor several multi-host viruses with a mostly fecal–oral between-species transmission route, provide an excellent system with which to test for the impact of biotic and abiotic factors on viral prevalence in wild host populations. Here we show on a continental scale that the prevalence of three broad host viruses: the AKI-complex (Acute bee paralysis virus, Kashmir bee virus and Israeli acute paralysis virus), Deformed wing virus, and Slow bee paralysis virus in wild bee populations (bumble bees and solitary bees) is positively related to viral prevalence of sympatric honey bees as well as being impacted by climatic variables. The former highlights the need for good beekeeping practices, including Varroa destructor management to reduce honey bee viral infection and hive placement. Furthermore, we found that viral prevalence in wild bees is at its lowest at the extreme ends of both temperature and precipitation ranges. Under predicted climate change, the frequency of extremes in precipitation and temperature will continue to increase and may hence impact viral prevalence in wild bee communities.

• Eldegard, Katrine; Flø, Daniel; Kirkendall, Lawrence Richard; Malmstrøm, Martin; Nielsen, Anders & Rasmussen, Claus [Show all 13 contributors for this article] (2022). Assessment of the risks to honey bees and biodiversity in Norway posed by the predatory wasp species Vespa velutina and V. mandarinia - Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered species of the Norwegian Scientific Committee for Food and Enviroment. VKM Report. Full text in Research Archive Show summary

  Med varmere klima er det mulig at asiatisk geithams (Vespa velutina) kan spre seg til Norge. Det er usannsynlig at japansk geithams (Vespa mandarina) vil spre seg til Norge.

• Nielsen, Anders; Måren, Inger Elisabeth; Rosef, Line; Kirkendall, Lawrence Richard; Malmstrøm, Martin & Boer, Hugo de [Show all 15 contributors for this article] (2021). Assessment of possible adverse consequences for biodiversity when planting vascular plants outside their natural range in Norway - Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered species (CITES) of the Norwegian Scientific Committee for Food and Environment (VKM). VKM Report. 2021(15), p. 1–97. Full text in Research Archive Show summary

  We sow or plant vascular plant species on a large scale in revegetation and restoration projects in Norway today. Some of the species used are already found in Norway, but many of the species, subspecies or populations used though native are not local, that is, they are regionally alien. A regionally alien species is a species that is native to Norway (has been in Norway since 1800) somewhere in the country, but which has been spread by humans to places in Norway where they do not occur. In theory, and according to the Biodiversity Act, it is desirable to use local seeds or plants to preserve local biodiversity. The aim of this report is to define guidelines that helps prevent the planting of vascular plant species with a high potential for negative effects on local biodiversity. It is assumed that the native or local populations are better adapted to local environmental conditions than populations from other areas or regions, and the risk of harmful genetic changes is therefore considered small when using local plant and seed sources. Arriving at a common definition for the area within which plants are “local” is difficult, though; vascular plant species are numerous (3317 species in mainland Norway, of which more than half are alien species introduced after 1800, Artdatabanken 2015), have different growth forms, different environmental requirements, and different reproductive and dispersal ecology. Even closely related vascular plant species can differ in such characteristics and hence in the extent of the "place" or “area”. The dispersal ecology of a plant species is of great importance for whether the species has genetically distinct populations within its range or not. Different strategies (wind pollination vs. insect pollination, vegetative propagation vs. seed dispersal, large seeds vs. small seeds) have an impact on the degree of gene flow between populations and thus also how locally adapted the species is in different areas. Whether the species has primarily vegetative reproduction or whether it spreads mainly by means of seeds, and whether the seed dispersal takes place ballistically, with wind or water, or by zookori (attached to animals or eaten by animals) determines how far the species can spread and how large gene flow there is between different populations. Whether the species is pollinated by wind or by the help of insects also affects the degree of gene flow differently. In Norway, there is great variation in many biophysical and ecological conditions (climate, topography, hydrology, and geology) over relatively short distances. This means that species that grow only a few meters apart can grow under different environmental conditions. This large variation in environmental conditions - on different spatial scales - can give rise to local genetic adaptation. However, plants have been moved around the landscape for several hundred years by our livestock (as seeds in fur and hooves, and in faeces) from lowland pasture to mountain pasture and along traffic arteries across the country due to the extensive transport of animals and people. Over time, this has led to expanded geographical distribution for several species and increased gene flow between populations over relatively large distances. .............

• Velle, Gaute; Edsman, Lennart; Evangelista, Charlotte; Johnsen, Stein Ivar; Malmstrøm, Martin & Vrålstad, Trude [Show all 17 contributors for this article] (2021). Assessment of the risk to Norwegian biodiversity from import and keeping of crustaceans in freshwater aquaria. Scientific Opinion of the Panel on Alien Organisms and trade in Endangered Species (CITES) of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2021(02), p. 1–377. Full text in Research Archive Show summary

  Key words: Risk assessment, Crayfish, Shrimps, Crabs, Climate change, Aphanomyces astaci, White spot syndrome, Alien species, Biological invasion Introduction The Norwegian Scientific Committee for Food and Environment (VKM) was requested by the Norwegian Environment Agency to assess the risk of negative impacts to biodiversity in Norway resulting from import of crustacean decapods for keeping in freshwater aquariums. VKM was asked to 1) list species of crayfish, crabs and shrimps that are currently kept in freshwater aquaria in Norway, and species that are likely to be kept in freshwater aquaria in Norway within the next 10 years, 2) assess the ability of the species to survive under Norwegian conditions and cause impacts on ecosystems and other species, and 3) state the potential negative effects on the biological diversity of diseases caused by pathogens, regulated under the Norwegian Food Act. Methods The risk assessment, without focus on pathogens, was performed in two steps. First, we used a pre-screening toolkit to identify species of crayfish, crabs and shrimps with potential to become invasive in freshwater habitats in Norway. Each species was given an invasiveness score based on 55 questions on biogeography, ecology, and climate change. In a second step, a full risk assessment, including the potential impacts of pathogens, was conducted on those species receiving the highest invasiveness score. This assessment included questions on the organism’s probability of entry and pathways of entry, establishment and spread, potential impacts on biodiversity, and how climate change scenarios might affect the assessment. Likelyhood and confidence was assessed for each question. In conclusion, each species was designated as either low-, moderate-, or high risk. Many crustacean decapod species are confirmed or suspected carriers of pathogens that can cause mass mortality among native crustaceans. The risk posed by crustaceans as carriers of pathogens may be independent of the environmental risk that they pose through ecological interactions. Therefore, the four crustacean disease pathogens that are regulated under the Norwegian Food Act, were assessed separately. These include Aphanomyces astaci causing crayfish plague, white spot syndrome virus (WSSV) causing white spot disease, Taura syndrome virus (TSV) causing Taura syndrome, and yellow head virus genotype 1 (YHV1) causing yellow head disease. The assessments comprised questions on the pathogen’s probability of entry (as a hitchhiker organism with imported crustaceans), pathways of entry, establishment and spread, and potential impact on crustacean biodiversity. Likelihood and confidence were assessed for each question. In conclusion, each pathogen was designated as either low-, moderate-, or high risk. In a third step, we categorized the likelihood that a crustacean species introduces a pathogen associated with a high- or moderate risk into: I) known chronic carriers, II) suspected chronic carriers, III) suspected situational carrier, IV) possible pathogen transmitters, and V) no direct or circumstantial evidence for carrier status or pathogen transmission in the genus. Results Based on information from the Norwegian Pet Trade Association, the project group listed 112 taxa (mainly species and some genera) of freshwater crayfish, crabs and shrimps that are relevant for trade in Norway. These included 38 crayfish taxa, 28 crab taxa, and 45 shrimp taxa. In addition, one marine crab was included. Sixteen species of crayfish, four species of shrimps, and two species of crabs underwent a full ecological risk assessment. The probabilities of entry both into the aquarium trade in Norway, and potentially further into Norwegian nature, were based on the prevalence of the species in the aquarium trade in Norway. We assumed that all species were equally likely to escape captivity or to be .........

• Bodin, Johanna Eva; Thorstensen, Tage; Alsheikh, Muath K; Basic, Dean; Edvardsen, Rolf Brudvik & Dalen, Knut Tomas [Show all 41 contributors for this article] (2021). Genome editing in food and feed production – implications for risk assessment. Scientific Opinion of the Scientific Steering Committee of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2021(18). Full text in Research Archive Show summary

  The Norwegian Scientific Committee for Food and Environment (VKM) initiated this work to examine the extent to which organisms developed by genome-editing technologies pose new challenges in terms of risk assessment. This report considers whether the risk assessment guidance on genetically modified organisms, developed by the European Food Safety Authority (EFSA), can be applied to evaluate potential risks of organisms developed by genome editing. Background Gene technology has allowed for the transfer of genes between organisms and species, and thereby to design altered genotypes with novel traits, i.e. GMOs. A new paradigm started in the early 2000s with the development of genome-editing techniques. Unlike traditional genetic modification techniques resulting in insertion of foreign DNA fragments at random locations in the genome, the new genome-editing techniques additionally open for a few single nucleotide edits or short insertions/deletions at a targeted site in an organism’s genome. These new techniques can be applied to most types of organisms, including plants, animals and microorganisms of commercial interest. An important question is how the novel, genome-edited organisms should be evaluated with respect to risks to health and the environment. The European Court of Justice decided in 2018 to include genome-edited organisms in the GMO definition and hence in the regulatory system already in place. This implies that all products developed by genome-editing techniques must be risk-assessed within the existing regulatory framework for GMOs. The European and Norwegian regulatory frameworks regulate the production, import and placing on the market of food and feed containing, consisting of or produced from GMOs, as well as the release of GMOs into the environment. The assessment draws on guidance documents originally developed by EFSA for risk assessment of GMOs, which were drawn up mainly to address risks regarding insertion of transgenes. The new genome-editing techniques, however, provide a new continuum of organisms ranging from those only containing a minor genetic alteration to organisms containing insertion or deletion of larger genomic regions. Risk assessment of organisms developed by genome editing The present discourse on how new genome-editing techniques should be regulated lacks an analysis of whether risk assessment methodologies for GMOs are adequate for risk assessment of organisms developed through the use of the new genome-editing techniques. Therefore, this report describes the use of genome-editing techniques in food and feed production and discusses challenges in risk assessment with the regulatory framework. Specifically, this report poses the question as to whether the EFSA guidance documents are sufficient for evaluating risks to health and environment posed by genome-edited plants, animals and microorganisms. To address these questions, the report makes use of case examples relevant for Norway. These examples, intended for food and feed, include oilseed rape with a modified fatty acid profile, herbicide-tolerant and pest-resistant crops, sterile salmon, virus-resistant pigs and hornless cattle. The report considers all aspects of the stepwise approach as described in the EFSA guidance documents. Conclusions The inherent flexibility of the EFSA guidance makes it suitable to cover health and environmental risk assessments of a wide range of organisms with various traits and intended uses. Combined with the embedded case-by-case approach the guidance is applicable to genome-edited organisms. The evaluation of the guidance demonstrates that the parts of the health and environmental risk assessment concerned with novel traits (i.e. the phenotype of the organism) may be fully applied to all categories of genome-edited organisms. ............

• Thorstad, Eva Bonsak; Garseth, Åse Helen; Gjøen, Tor; Gulla, Snorre; Lo, Håvard & Malmstrøm, Martin [Show all 22 contributors for this article] (2021). Assessment of the risk of negative impact on biodiversity from import and release of eggs or live fish from landlocked Atlantic salmon from Klarälven in Sweden to Trysilelva in Norway. Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered Species of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2021(04). Full text in Research Archive Show summary

  Introduction Atlantic salmon in the River Klarälven in Sweden live the entire life in freshwater, undertaking feeding migrations to Lake Vänern. The upper part of the watershed is in Norway and comprises the River Trysilelva and associated rivers and lakes. Atlantic salmon previously lived in the Norwegian part of the watershed but were lost due to the construction of 11 hydropower stations that block the upstream migration from Vänern. The power stations also cause a high mortality among downstream migrating fish. Tagging studies showed that there is 71-84% mortality of juveniles (smolts) and 100% mortality of adults during downstream migration past the eight lowermost power stations. Extensive mitigation measures are needed to reduce the mortality of downstream migrants and reestablish a population that can reach areas in Norway naturally without being captured in Sweden and transported to Norway. In 2015, the total costs of establishing fishways bypassing the power stations and securing safe downstream migration was estimated to be 1000 million SEK. To compensate for a decline of salmon due to lost habitat, hatchery-produced juveniles have been released in the watershed for more than 100 years, and adult salmon have been captured in the lower reaches of Klarälven and released in upstream reaches. After the Höljes power station was built, 80% of the salmon transported upstream were released upstream of Höljes. In 1993, the Norwegian government stopped these releases due to the large mortality of downstream migrating fish at the power stations. The releases had already been stopped from late summer 1988 due to bacterial kidney disease (BKD) outbreaks in salmon populations in the watershed. Since 1988, transported fish have been released upstream of Edsforsen in Sweden, and have not been able to reach Norway. Aim of report The Norwegian Environment Agency asked VKM to carry out a risk assessment of three specified methods that can be used to reestablish salmon in the Norwegian part of the watershed. This risk assessment is pertinent because the occurrence of alien organisms and infectious agents have developed differently in the Swedish and Norwegian parts of the watershed after salmon became unable to migrate through the river system. In 2013, the fish parasite Gyrodactylus salaris was detected in Klarälven, but has not been recorded in Norwegian parts of the watershed. Here, we assess the risk of negative impacts on native biodiversity by importing Atlantic salmon eggs or live adults from Klarälven to Norway. Three methods of importing eggs or adults were assessed: I. Import of fertilised eggs to a local hatchery in Norway, which are planted in the river in the spring or hatched and released as juveniles or smolts. II. Import of fertilised eggs that will be used to establish a long-term broodstock in Norway using the gene bank model, from which eggs can be planted into the river, or transferred to a local hatchery with subsequent release of juveniles or smolts. III. Import of adult salmon spawners that are captured in the lower parts of Klarälven in Sweden, transported in tanks and released in the Norwegian parts of the watershed. Methods The risk assessment was based on a literature review and qualitative assessment of each of the three methods of importing eggs or adults. The risk of impacts on native biodiversity and ecosystems was assessed for infectious agents, including parasites, bacterial pathogens, and viruses, and for other alien species. For each of the infectious agents and alien species, the risk is based on the product of the magnitude of the potential negative impact to native biodiversity and ecosystems, and the likelihood that negative consequences occur. The risk assessment concludes in terms of low, moderate, or high risk. .......................

• Vilizzi, Lorenzo; Copp, Gordon H.; Hill, Jeffrey E.; Adamovich, Boris; Aislabie, Luke & Akin, Daniel [Show all 61 contributors for this article] (2021). A global-scale screening of non-native aquatic organisms to identify potentially invasive species under current and future climate conditions. Science of the Total Environment. ISSN 0048-9697. 788, p. 1–16. doi: 10.1016/j.scitotenv.2021.147868. Full text in Research Archive Show summary

  The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment areas across all six inhabited continents screened 819 non-native species from 15 groups of aquatic organisms (freshwater, brackish, marine plants and animals) using the Aquatic Species Invasiveness Screening Kit. This multi-lingual decision-support tool for the risk screening of aquatic organisms provides assessors with risk scores for a species under current and future climate change conditions that, following a statistically based calibration, permits the accurate classification of species into high-, medium-and low-risk categories under current and predicted climate conditions. The 1730 screenings undertaken encompassed wide geographical areas (regions, political entities, parts thereof, water bodies, river basins, lake drainage basins, and marine regions), which permitted thresholds to be identified for almost all aquatic organismal groups screened as well as for tropical, temperate and continental climate classes, and for tropical and temperate marine ecoregions. In total, 33 species were identified as posing a 'very high risk' of being or becoming invasive, and the scores of several of these species under current climate increased under future climate conditions, primarily due to their wide thermal tolerances. The risk thresholds determined for taxonomic groups and climate zones provide a basis against which area-specific or climate-based calibrated thresholds may be interpreted. In turn, the risk rankings help decision-makers identify which species require an immediate 'rapid' management action (e.g. eradication, control) to avoid or mitigate adverse impacts, which require a full risk assessment, and which are to be restricted or banned with regard to importation and/or sale as ornamental or aquarium/fishery enhancement. Decision support tools AS-ISK Hazard identification Non-native species Risk analysis Climate change

• Nilsen, Erlend Birkeland; Austrheim, Gunnar; Gjøen, Tor; Kvie, Kjersti Sternang; Malmstrøm, Martin & Ytrehus, Bjørnar [Show all 15 contributors for this article] (2021). Assessment of the risk to Norwegian biodiversity from import and keeping of American bison, European bison, domesticated water buffalo and domesticated yak. Scientific Opinion of the panel on Alien Organisms and Trade in Endangered Species (CITES) of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2021(20), p. 1–77. Full text in Research Archive
• Hindar, Kjetil; Hole, Lars Robert; Kausrud, Kyrre Linné; Malmstrøm, Martin; Rimstad, Espen & Robertson, Lucy [Show all 18 contributors for this article] (2020). Assessment of the risk to Norwegian biodiversity and aquaculture from pink salmon (Oncorhynchus gorbuscha). Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered Species (CITES) of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2020(01), p. 1–157. Full text in Research Archive Show summary

  Key words: VKM, risk assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Environment Agency, Norwegian Food Safety Authority Introduction: The Norwegian Environment Agency and the Norwegian Food Safety Authority asked the Norwegian Scientific Committee for Food and Environment to assess the risk to Norwegian biodiversity, to the productivity of native salmonid populations, and to aquaculture, from the spread and establishment of pink salmon in Norwegian rivers, and to assess mitigation measures to prevent the spread and establishment of this alien species. Pink salmon is native to rivers around the northern Pacific Ocean. The species usually has a strict two-year life cycle, with populations spawning in even and odd years being genetically isolated. Fertilized eggs of pink salmon were transferred from Sakhalin Island to Northwest Russia in the late 1950s, and fry were released in rivers draining to the White Sea. The first abundant return to rivers in Northwest Russia, as well as to Norway and other countries in northwestern Europe, was recorded in 1960. Stocking with fish from Sakhalin was terminated in 1979. By then, no self-sustaining populations had been established. From 1985 onwards, stocking in White Sea rivers was resumed with fish from rivers in the more northerly Magadan oblast on the Russian Pacific, resulting in the establishment of reproducing populations. Stocking was continued until 1999, when the last batch of evenyear fertilized eggs was imported, and the fry released in spring 2000. Thus, all pink salmon caught after 2001 in the Northeast Atlantic and the Atlantic side of the Arctic Ocean including the Barents Sea, as well as in rivers draining into these seas, are the result of reproduction in the wild. Pink salmon is now established with abundant and increasing stocks in Northwest Russia and regular occurrence in rivers in eastern Finnmark. Catches of odd-year adult pink salmon in Northwest Russia were usually below 100 tonnes before 2001 and increased to an annual average of 220.5 tonnes during the period 2001-2017. Even-year returns are smaller than odd-year returns both in Northwest Russia and in Norway. The number of pink salmon recorded in Norwegian rivers peaked in 2017, with a high number of fish in eastern Finnmark, and substantial numbers recorded in rivers all along the coast of Norway and in other European countries. In 2019, the area with abundant returns expanded in comparison with 2017, to include rivers in western Finnmark and Troms. The recorded numbers were perhaps lower in southern Norway in 2017 than in 2019 (full statistics not available when this report was finalised), but also in southern Norway there were more pink salmon in 2019 than in any year before 2017. The large numbers of pink salmon in western Finnmark and Troms in 2019 may indicate an expansion of the area in Norway with abundant odd-year pink salmon returns. In some small rivers in eastern Finnmark, between 1000 and 1500 pink salmon were fished out by local people in 2019, demonstrating the magnitude of the potential impact in terms of numbers of pink salmon. We cannot rule out that this will not happen over larger parts of Norway in the coming years. The even-year strain of pink salmon only occurs in low numbers in Russian rivers, as well as Norwegian, rivers. Adult pink salmon enter the rivers from early July, and spawning occurs in AugustSeptember. Spawning habitat requirements are like those of native salmonids: Atlantic salmon, brown trout, and Arctic charr. Spawning of pink salmon occurs earlier than the native salmonids, but observations in 2019 indicate a possible overlap with native salmonids in September in northern Norway. . Pink salmon eggs hatch in late winter or spring, and the alevins remain in the gravel until most of the yolk sac has been resorbed. Emerging fry are approximately 30 mm in length. ...................

• Musilova, Zuzana; Cortesi, Fabio; Matschiner, Michael; Davies, Wayne I. L.; Patel, Jagdish Suresh & Stieb, Sara M. [Show all 18 contributors for this article] (2019). Vision using multiple distinct rod opsins in deep-sea fishes. Science. ISSN 0036-8075. 364(6440), p. 588–592. doi: 10.1126/science.aav4632. Full text in Research Archive
• Malmstrøm, Martin; Britz, Ralf; Matschiner, Michael; Tørresen, Ole K.; Hadiaty, Renny Kurnia & Yaakob, Norsham [Show all 10 contributors for this article] (2018). The Most Developmentally Truncated Fishes Show Extensive Hox Gene Loss and Miniaturized Genomes. Genome Biology and Evolution (GBE). 10(4), p. 1088–1103. doi: 10.1093/gbe/evy058. Full text in Research Archive Show summary

  The world’s smallest fishes belong to the genus Paedocypris. These miniature fishes are endemic to an extreme habitat: the peat swamp forests in Southeast Asia, characterized by highly acidic blackwater. This threatened habitat is home to a large array of fishes, including a number of miniaturized but also developmentally truncated species. Especially the genus Paedocypris is characterized by profound, organism-wide developmental truncation, resulting in sexually mature individuals of <8 mm in length with a larval phenotype. Here, we report on evolutionary simplification in the genomes of two species of the dwarf minnow genus Paedocypris using whole-genome sequencing. The two species feature unprecedented Hox gene loss and genome reduction in association with their massive developmental truncation. We also show how other genes involved in the development of musculature, nervous system, and skeleton have been lost in Paedocypris, mirroring its highly progenetic phenotype. Further, our analyses suggest two mechanisms responsible for the genome streamlining in Paedocypris in relation to other Cypriniformes: severe intron shortening and reduced repeat content. As the first report on the genomic sequence of a vertebrate species with organism-wide developmental truncation, the results of our work enhance our understanding of genome evolution and how genotypes are translated to phenotypes. In addition, as a naturally simplified system closely related to zebrafish, Paedocypris provides novel insights into vertebrate development.

• Malmstrøm, Martin; Matschiner, Michael; Tørresen, Ole Kristian; Jakobsen, Kjetill Sigurd & Jentoft, Sissel (2017). Whole genome sequencing data and de novo draft assemblies for 66 teleost species. Scientific Data. 4, p. 1–13. doi: 10.1038/sdata.2016.132. Full text in Research Archive Show summary

  Teleost fishes comprise more than half of all vertebrate species, yet genomic data are only available for 0.2% of their diversity. Here, we present whole genome sequencing data for 66 new species of teleosts, vastly expanding the availability of genomic data for this important vertebrate group. We report on de novo assemblies based on low-coverage (9–39×) sequencing and present detailed methodology for all analyses. To facilitate further utilization of this data set, we present statistical analyses of the gene space completeness and verify the expected phylogenetic position of the sequenced genomes in a large mitogenomic context. We further present a nuclear marker set used for phylogenetic inference and evaluate each gene tree in relation to the species tree to test for homogeneity in the phylogenetic signal. Collectively, these analyses illustrate the robustness of this highly diverse data set and enable extensive reuse of the selected phylogenetic markers and the genomic data in general. This data set covers all major teleost lineages and provides unprecedented opportunities for comparative studies of teleosts.

• Baalsrud, Helle Tessand; Voje, Kjetil L.; Tørresen, Ole Kristian; Solbakken, Monica Hongrø; Matschiner, Michael & Malmstrøm, Martin [Show all 10 contributors for this article] (2017). Evolution of Hemoglobin Genes in Codfishes Influenced by Ocean Depth. Scientific Reports. 7, p. 1–10. doi: 10.1038/s41598-017-08286-2. Full text in Research Archive Show summary

  Understanding the genetic basis of adaptation is one of the main enigmas of evolutionary biology. Among vertebrates, hemoglobin has been well documented as a key trait for adaptation to different environments. Here, we investigate the role of hemoglobins in adaptation to ocean depth in the diverse teleost order Gadiformes, with species distributed at a wide range of depths varying in temperature, hydrostatic pressure and oxygen levels. Using genomic data we characterized the full hemoglobin (Hb) gene repertoire for subset of species within this lineage. We discovered a correlation between expanded numbers of Hb genes and ocean depth, with the highest numbers in species occupying shallower, epipelagic regions. Moreover, we demonstrate that the Hb genes have functionally diverged through diversifying selection. Our results suggest that the more variable environment in shallower water has led to selection for a larger Hb gene repertoire and that Hbs have a key role in adaptive processes in marine environments.

• Malmstrøm, Martin; Matschiner, Michael; Tørresen, Ole Kristian; Star, Bastiaan; Snipen, Lars-Gustav & Hansen, Thomas F [Show all 13 contributors for this article] (2016). Evolution of the immune system influences speciation rates in teleost fishes. Nature Genetics. ISSN 1061-4036. 48(10), p. 1204–1210. doi: 10.1038/ng.3645. Full text in Research Archive Show summary

  Teleost fishes constitute the most species-rich vertebrate clade and exhibit extensive genetic and phenotypic variation, including diverse immune defense strategies. The genomic basis of a particularly aberrant strategy is exemplified by Atlantic cod, in which a loss of major histocompatibility complex (MHC) II functionality coincides with a marked expansion of MHC I genes. Through low-coverage genome sequencing (9–39×), assembly and comparative analyses for 66 teleost species, we show here that MHC II is missing in the entire Gadiformes lineage and thus was lost once in their common ancestor. In contrast, we find that MHC I gene expansions have occurred multiple times, both inside and outside this clade. Moreover, we identify an association between high MHC I copy number and elevated speciation rates using trait-dependent diversification models. Our results extend current understanding of the plasticity of the adaptive immune system and suggest an important role for immune-related genes in animal diversification.

• Gante, Hugo F; Matschiner, Michael; Malmstrøm, Martin; Jakobsen, Kjetill Sigurd; Jentoft, Sissel & Salzburger, Walter (2016). Genomics of speciation and introgression in Princess cichlid fishes from Lake Tanganyika. Molecular Ecology. ISSN 0962-1083. 25(24), p. 6143–6161. doi: 10.1111/mec.13767. Full text in Research Archive Show summary

  How variation in the genome translates into biological diversity and new species originate has endured as the mystery of mysteries in evolutionary biology. African cichlid fishes are prime model systems to address speciation-related questions for their remarkable taxonomic and phenotypic diversity, and the possible role of gene flow in this process. Here, we capitalize on genome sequencing and phylogenomic analyses to address the relative impacts of incomplete lineage sorting, introgression and hybrid speciation in the Neolamprologus savoryi-complex (the ‘Princess cichlids’) from Lake Tanganyika. We present a time-calibrated species tree based on whole-genome sequences and provide strong evidence for incomplete lineage sorting in the early phases of diversification and multiple introgression events affecting different stages. Importantly, we find that the Neolamprologus chromosomes show centre-to-periphery biases in nucleotide diversity, sequence divergence, GC content, incomplete lineage sorting and rates of introgression, which are likely modulated by recombination density and linked selection. The detection of heterogeneous genomic landscapes has strong implications on the genomic mechanisms involved in speciation. Collinear chromosomal regions can be protected from gene flow and harbour incompatibility genes if they reside in lowly recombining regions, and coupling can evolve between nonphysically linked genomic regions (chromosome centres in particular). Simultaneously, higher recombination towards chromosome peripheries makes these more dynamic, evolvable regions where adaptation polymorphisms have a fertile ground. Hence, differences in genome architecture could explain the levels of taxonomic and phenotypic diversity seen in taxa with collinear genomes and might have contributed to the spectacular cichlid diversity observed today.

• Cortesi, Fabio; Musilováa, Zuzana; Stieb, Sara M.; Hart, Nathan S.; Siebeck, Ulrike E. & Malmstrøm, Martin [Show all 12 contributors for this article] (2015). Ancestral duplications and highly dynamic opsin gene evolution in percomorph fishes. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 112(5), p. 1493–1498. doi: 10.1073/pnas.1417803112. Full text in Research Archive
• Malmstrøm, Martin; Jentoft, Sissel; Gregers, Tone Fredsvik & Jakobsen, Kjetill Sigurd (2013). Unraveling the Evolution of the Atlantic Cod’s (Gadus morhua L.) Alternative Immune Strategy. PLOS ONE. 8(9). doi: 10.1371/journal.pone.0074004. Full text in Research Archive Show summary

  Genes encoding the major histocompatibility complex (MHC) have been thought to play a vital role in the adaptive immune system in all vertebrates. The discovery that Atlantic cod (Gadus morhua) has lost important components of the MHC II pathway, accompanied by an unusually high number of MHC I genes, shed new light on the evolution and plasticity of the immune system of teleosts as well as in higher vertebrates. The overall aim of this study was to further investigate the highly expanded repertoire of MHC I genes using a cDNA approach to obtain sequence information of both the binding domains and the sorting signaling potential in the cytoplasmic tail. Here we report a novel combination of two endosomal sorting motifs, one tyrosine-based associated with exogenous peptide presentation by cross-presenting MHCI molecules, and one dileucine-based associated with normal MHC II functionality. The two signal motifs were identified in the cytoplasmic tail in a subset of the genes. This indicates that these genes have evolved MHC II-like functionality, allowing a more versatile use of MHC I through cross-presentation. Such an alternative immune strategy may have arisen through adaptive radiation and acquisition of new gene function as a response to changes in the habitat of its ancestral lineage. Copyright: 2013 Malmstrøm et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

• Star, Bastiaan; Nederbragt, Alexander Johan; Jentoft, Sissel; Grimholt, Unni; Malmstrøm, Martin & Gregers, Tone Fredsvik [Show all 42 contributors for this article] (2011). The genome sequence of Atlantic cod reveals a unique immune system. Nature. ISSN 0028-0836. 477(7363), p. 207–210. doi: 10.1038/nature10342. Full text in Research Archive Show summary

  Atlantic cod (Gadus morhua) is a large, cold-adapted teleost that sustains long-standing commercial fisheries and incipient aquaculture. Here we present the genome sequence of Atlantic cod, showing evidence for complex thermal adaptations in its haemoglobin gene cluster and an unusual immune architecture compared to other sequenced vertebrates. The genome assembly was obtained exclusively by 454 sequencing of shotgun and paired-end libraries, and automated annotation identified 22,154 genes. The major histocompatibility complex (MHC) II is a conserved feature of the adaptive immune system of jawed vertebrates, but we show that Atlantic cod has lost the genes for MHC II, CD4 and invariant chain (Ii) that are essential for the function of this pathway. Nevertheless, Atlantic cod is not exceptionally susceptible to disease under natural conditions5. We find a highly expanded number of MHC I genes and a unique composition of its Toll-like receptor (TLR) families. This indicates how the Atlantic cod immune system has evolved compensatory mechanisms in both adaptive and innate immunity in the absence of MHC II. These observations affect fundamental assumptions about the evolution of the adaptive immune system and its components in vertebrates.

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• Velle, Gaute; Sandercock, Brett Kevin; Kausrud, Kyrre; Kirkendall, Lawrence R.; Bryn, Anders & Malmstrøm, Martin (2026). Fremmede arter opptrer i flokk – men vurderes som regel alene. Forskersonen.no. doi: https:/www.forskersonen.no/artsdatabanken-klima-kronikk/dette-har-kongekrabbe-rynkerose-og-sitkagran-til-felles/2632734. Full text in Research Archive Show summary

  Arter flytter på seg, på grunn av klimaendringer, global handel og menneskers arealbruk. Fremmede skadelige arter er en av de største globale truslene mot økosystemene, med store følger for biologisk mangfold, økonomi, matsikkerhet og helse. Når Vitenskapskomiteen for mat og miljø (VKM) vurderer «fremmede organismer», vurderer vi som regel risikoen ved slike arter hver for seg. Vi gir arter kategorier, som «høy risiko» eller «svært høy risiko», basert på en kombinasjon av effekt på biologisk mangfold og sannsynlighet. Men naturen fungerer ikke slik. I naturen møter arter hverandre. Fremmede arter kan forsterke hverandres effekter eller svekke dem. I en ny rapport har VKM vurdert om slike samspill mellom fremmede arter kan tas inn i risikovurderinger.

• Kausrud, Kyrre; Malmstrøm, Martin; Stenseth, Nils Christian & Hjelle, Dag (2021). Koronaviruset – pandemi eller kommet for å bli? Aftenposten Viten. ISSN 2464-3033. Full text in Research Archive
• Vrålstad, Trude; Nielsen, Anders; Dolmen, Dag; Jacob, Höglund; Kausrud, Kyrre & Malmstrøm, Martin [Show all 8 contributors for this article] (2019). The risk of Bd and Bsal to Norwegian amphibian biodiversity. Full text in Research Archive
• Vrålstad, Trude; Nielsen, Anders; Dolmen, Dag; Jacob, Höglund; Kausrud, Kyrre & Malmstrøm, Martin [Show all 8 contributors for this article] (2019). Risk assessment for amphibian diseases. Full text in Research Archive
• Baalsrud, Helle Tessand; Tørresen, Ole Kristian; Malmstrøm, Martin; Salzburger, Walter; Jakobsen, Kjetill Sigurd & Jentoft, Sissel (2015). The hemoglobin repertoire in the order of Gadiformes linked to depth adaptation. Full text in Research Archive
• Malmstrøm, Martin; Sydenham, Markus A. K. & Nielsen, Anders (2015). CEES, its people and machines - a goldmine for genetic studies. Full text in Research Archive
• Malmstrøm, Martin (2013). The 90+ teleost genome project. Full text in Research Archive
• Malmstrøm, Martin (2013). Life without MHC II - a teleost genome project. Full text in Research Archive
• Solbakken, Monica Hongrø; Malmstrøm, Martin; Tørresen, Ole Kristian; Jakobsen, Kjetill Sigurd & Jentoft, Sissel (2013). Atlantic cod displays an unusual TLR repertoire – a Gadidae-specific feature? Full text in Research Archive
• Malmstrøm, Martin (2012). The 60+ teleost genome project. Full text in Research Archive
• Nederbragt, Alexander Johan; Lagesen, Karin & Malmstrøm, Martin (2011). Bioinformatic analysis of genomic data. Full text in Research Archive
• Star, Bastiaan; Nederbragt, Alexander Johan; Jentoft, Sissel; Grimholt, Unni; Malmstrøm, Martin & Gregers, Tone Fredsvik [Show all 18 contributors for this article] (2011). The genome of Atlantic cod reveals a unique immune system. Full text in Research Archive
• Grimholt, Unni; Malmstrøm, Martin; Nederbragt, Alexander Johan; Rounge, Trine Ballestad; Jentoft, Sissel & Tooming-Klunderud, Ave [Show all 10 contributors for this article] (2009). The lack of cod MHC class II. Full text in Research Archive
• Grimholt, Unni; Nederbragt, Alexander Johan; Rounge, Trine Ballestad; Malmstrøm, Martin; Star, Bastiaan & Tooming-Klunderud, Ave [Show all 12 contributors for this article] (2009). The cod genome project. Full text in Research Archive
• Malmstrøm, Martin; Strømnes, Einar; Hansen, Rune Roland & Ugland, Karl Inne (2007). The nematode Cucullanus heterochrous; a possible indicator species for marine xenobiotics. Full text in Research Archive
• Eldegard, Katrine; Flø, Daniel; Kirkendall, Lawrence R.; Malmstrøm, Martin; Nielsen, Anders & Rasmussen, Claus [Show all 13 contributors for this article] (2022). Assessment of the risks to honey bees and biodiversity in Norway posed by the predatory wasp species Vespa velutina and V. mandarina. VKM. ISSN 9788282593861. Full text in Research Archive
• Nielsen, Anders; Dolmen, Dag; Höglund, Jacob; Kausrud, Kyrre; Malmstrøm, Martin & Taugbøl, Annette [Show all 14 contributors for this article] (2019). Assessment of the risk to Norwegian biodiversity from the pathogenic fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Opinion of the Panel on Alien Organisms and Trade in Endangered Species (CITES) of the Norwegian Scientific Committee for Food and Environment. Norwegian Scientific Committee for Food and Environment (VKM). ISSN 9788282593205. Full text in Research Archive
• Rueness, Eli Knispel; Berg, Paul Ragnar; Gulla, Snorre; Halvorsen, Kim Aleksander Tallaksen; Järnegren, Johanna & Malmstrøm, Martin [Show all 19 contributors for this article] (2019). Assessment of the risk to Norwegian biodiversity from import of wrasses and other cleaner fish for use in aquaculture. Opinion of the Panel on Alien Organisms and Trade in Endangered Species of the Norwegian Scientific Committee for Food and Environment. Norwegian Scientific Committee for Food and Environment (VKM). ISSN 9788282593304. Full text in Research Archive
• Skjerve, Eystein; Thurfjell, Henrik; Flø, Daniel; Grahek-Ogden, Danica; Malmstrøm, Martin & Nesbakken, Truls [Show all 17 contributors for this article] (2018). Wild boar population growth and expansion – implications for biodiversity, food safety, and animal health in Norway. Opinion of the Norwegian Scientific Committee for Food and Environment. Norwegian Scientific Committee for Food and Environment (VKM). ISSN 9788282593113. Full text in Research Archive
• Nielsen, Anders; Hatteland, Bjørn Arild; Malmstrøm, Martin; Proschwitz, Ted von; Velle, Gaute & Boer, Hugo de [Show all 10 contributors for this article] (2017). Assessment of the risk to Norwegian biodiversity from the import and keeping of terrestrial gastropods in terraria. Opinion of the Panel on Alien Organisms and Trade in Endangered Species of the Norwegian Scientific Committee for Food and Environment. Norwegian Scientific Committee for Food and Environment (VKM). ISSN 9788282592901. Full text in Research Archive

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