Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2023
Abstract
No abstract has been registered
Authors
Simo Maduna Ólöf Dóra Bartels Jónsdóttir Albert Kjartan Dagbjartarson Imsland Davíð Gíslason Patrick Reynolds Lauri Kapari Thor Arne Hangstad Kristian Meier Snorre HagenAbstract
Aquaculture of the lumpfish (Cyclopterus lumpus L.) has become a large, lucrative industry owing to the escalating demand for “cleaner fish” to minimise sea lice infestations in Atlantic salmon mariculture farms. We used over 10K genome-wide single nucleotide polymorphisms (SNPs) to investigate the spatial patterns of genomic variation in the lumpfish along the coast of Norway and across the North Atlantic. Moreover, we applied three genome scans for outliers and two genotype–environment association tests to assess the signatures and patterns of local adaptation under extensive gene flow. With our ‘global’ sampling regime, we found two major genetic groups of lumpfish, i.e., the western and eastern Atlantic. Regionally in Norway, we found marginal evidence of population structure, where the population genomic analysis revealed a small portion of individuals with a different genetic ancestry. Nevertheless, we found strong support for local adaption under high gene flow in the Norwegian lumpfish and identified over 380 high-confidence environment-associated loci linked to gene sets with a key role in biological processes associated with environmental pressures and embryonic development. Our results bridge population genetic/genomics studies with seascape genomics studies and will facilitate genome-enabled monitoring of the genetic impacts of escapees and allow for genetic-informed broodstock selection and management in Norway.
Authors
Juliana D. Klein Simo Maduna Matthew L. Dicken Charlene Da Silva Michelle Soekoe Meaghen E. McCord Warren M. Potts Snorre Hagen Aletta E Bester-van der MerweAbstract
Adaptive divergence in response to environmental clines are expected to be common in species occupying heterogeneous environments. Despite numerous advances in techniques appropriate for non-model species, gene–environment association studies in elasmobranchs are still scarce. The bronze whaler or copper shark (Carcharhinus brachyurus) is a large coastal shark with a wide distribution and one of the most exploited elasmobranchs in southern Africa. Here, we assessed the distribution of neutral and adaptive genomic diversity in C. brachyurus across a highly heterogeneous environment in southern Africa based on genome-wide SNPs obtained through a restriction site-associated DNA method (3RAD). A combination of differentiation-based genome-scan (outflank) and genotype–environment analyses (redundancy analysis, latent factor mixed models) identified a total of 234 differentiation-based outlier and candidate SNPs associated with bioclimatic variables. Analysis of 26,299 putatively neutral SNPs revealed moderate and evenly distributed levels of genomic diversity across sites from the east coast of South Africa to Angola. Multivariate and clustering analyses demonstrated a high degree of gene flow with no significant population structuring among or within ocean basins. In contrast, the putatively adaptive SNPs demonstrated the presence of two clusters and deep divergence between Angola and all other individuals from Namibia and South Africa. These results provide evidence for adaptive divergence in response to a heterogeneous seascape in a large, mobile shark despite high levels of gene flow. These results are expected to inform management strategies and policy at the national and regional level for conservation of C. brachyurus populations.
Authors
Albert Kjartan Dagbjartarson Imsland Patrick Reynolds Lauri Teemu Kapari Simo Maduna Snorre Hagen Anna Hanssen Ólöf Dóra Bartels JónsdóttirAbstract
The aim of this study was to evaluate whether sea lice grazing efficiency, behaviour, size variation and cataract development can be improved through selective breeding of lumpfish. A series of studies was conducted over a four-year period where distinctive lumpfish families were established initially from wild caught mature fish and latterly from established breeding lines. Four subsequent trials (called: Phase I-IV) with ten families of lumpfish (N = 480) with a mean (± SD) weight of 46.4 ± 9.4 g (Phase I), 54.8 ± 9.2 g (Phase II), 42.0 ± 7.4 g (Phase III) and 31.3 ± 2.4 g (Phase IV) were distributed among ten sea cages (5 × 5 × 5 m) during autumn 2018 to spring 2022, each stocked with 400–404 Atlantic salmon with an average initial mean (± SD) of 387 ± 9 g (Phase I), 621 ± 15 g (Phase II), 280 ± 16 g (Phase III) and 480 ± 66 g (Phase IV). All the ten cages were stocked with 48 lumpfish (12% stocking density). In all phases there was a large inter-family variation of lice grazing of lumpfish of both L. salmonis and C. elongatus. When sea lice grazing was scaled in relation to sea lice infestation numbers on the salmon the highest sea lice grazing activity was found in Phase IV and in particular in families sired from farmed parents. There was a general trend for mean start weights and standard deviations to decrease as the phases continued. A significant increase was found in frequency of behaviour associated with feeding on natural food sources and grazing sea lice from salmon during each subsequent phase. The increase in incidence of cataracts from start to end of each trial phase was significantly reduced from Phase I (16%) to Phase IV (2%). Overall, present findings showed that sea lice grazing of both L. salmonis and C. elongatus, size variation, cataract prevalence and behaviour types can be enhanced through selection and targeted breeding programs.
Abstract
No abstract has been registered
Authors
Mounir TakritiAbstract
No abstract has been registered
Abstract
To reduce the dependency of fungicides in treating turf grass diseases we investigated the use of biostimulants and colour pigments and their capacity to prevent the proliferation of microdochium and anthracnose on annual meadow grass (Poa annua). The study was conducted in two sites (Landvik, Norway and Bingley, United Kingdom) for two years (May 2020 – May 2022). The biostimulant Hicure could reduce the fungicidal use from three to two without loss of efficiency in treating the fungal diseases. The biostimulant also preserved the visual quality of the turf grasses when reducing the fungicidal treatment from three to two. The colour pigment Ryder in all treatments was effective at increasing the colour intensity of the turf grasses compared to the control. Additionally, the biostimulant treatments could treat anthracnose better than the fungicidal only treatment. The biostimulant Hicure and the colour pigment Ryder have potential for further research and development to reduce the use of fungicides while simultaneously preserving the pristine quality of turf grasses in golf greens.
Abstract
The adults of the new species Zachvatkinibates svanhovdi A. Seniczak & S. Seniczak sp. nov. are described and illustrated from Norway, and this is the first finding of Zachvatkinibates Shaldybina, 1973 in Fennoscandia. This species is the most similar to Z. quadrivertex (Halbert, 1920), but differs from it mainly by the shape of notogastral setae, posterior tectum of notogaster and lack of postanal porose area Ap, which in Z. quadrivertex is present. In Z. svanhovdi, the prodorsal seta in is long, translamella is narrow, notogastral setae are short and distally pliable, notogastral porose areas are usually oval and of medium size, but Aa can be larger, especially in males. Dorsal crest on tarsus I is present. The cytochrome oxidase I (COI) barcodes (length: 658 bp) of five specimens of the new species are provided; the maximum variation within the species was 2.41% (p-dist). The morphology and ecology of the new species is compared with other Zachvatkinibates species. The knowledge on family Punctoribatidae in Fennoscandia is updated, and Mycobates carli (Schweizer, 1922) is first reported from Norway.
Abstract
No abstract has been registered
Abstract
The morphological ontogeny of Nanhermannia sellnicki Forsslund, 1958 is described and illustrated. In all juvenile stages the bothridial seta is minute, and two pairs of exobothridial setae are present (exa reduced to its alveolus, exp short). In the larva, the seta f1 is setiform but in the nymphs it is unobservable among cuticular tubercles. Most prodorsal and gastronotal setae of the larva are short while thouse of nymphs are long; seta in and all gastronotal and adanal setae are inserted in small individual depressions. In all instars the leg segments are oval in cross section and relatively thick, and most setae on tarsi are relatively short, thick or conical. The seta d accompanies solenidion σ on all genua, φ1 on tibia I and φ on other tibiae.