Nicolas Dupont

• Olsen, Tora; Stige, Leif Christian; Dupont, Nicolas; Durant, Joël M & Langangen, Øystein Ole Gahr (2025). Reply to Bogstad et al. (2025) ‘Comment on “Repeated large declines in the Barents Sea capelin populations are associated with different ecosystem conditions” by Olsen et al. (2024)’. ICES Journal of Marine Science. ISSN 1054-3139. 82(4). doi: 10.1093/icesjms/fsaf054. Full text in Research Archive Show summary

  Herring predates on young capelin in the Barents Sea (BS), which affects the recruitment of BS capelin. However, our modelling study does not support the hypothesis that Bogstad et al. advocated that herring predation is necessary for the observed large declines (collapses) of the BS capelin population. What Bogstad et al. do not consider is the magnitude of the herring predation effect compared to other influences on the population dynamics of capelin. Our results suggest that while herring significantly reduced age-0 abundance of capelin at the start of the collapses, these reductions were probably not the main cause of the subsequent large population declines. All models have limitations, but we do not agree with Bogstad et al. that model limitations were the reason for our findings on the importance of herring predation for capelin biomass collapses.

• Årthun, Marius; Dinh, van Khuong; Dörr, Jakob Simon; Dupont, Nicolas; Fransner, Filippa & Nilsen, Ina [Show all 18 contributors for this article] (2025). The future Barents Sea- A synthesis of physical, biogeochemical, and ecological changes toward 2050 and 2100. Elementa: Science of the Anthropocene. 13(1), p. 1–17. doi: 10.1525/elementa.2024.00046. Full text in Research Archive Show summary

  Barentshavet er preget av sterke klimaendringene, som manifesterer seg i en rask oppvarming av havet og atmosfæren og en sterk nedgang i havisdekket om vinteren. Disse endringene i det fysiske miljøet har store konsekvenser for de marine økosystemene, inkludert de kommersielle fiskebestandene. I et varmere klima i fremtiden forventes både de fysiske og økologiske endringene å forsterkes. Her gir vi en første omfattende oversikt over framtidige klimaendringer i Barentshavet og de tilhørende fysiske, biogeokjemiske og økologiske konsekvensene basert på klimamodeller og helhetlige økosystemmodeller. Vi diskuterer også potensielle fremtidige endringer i menneskelige aktiviteter og konsekvensene av disse, inkludert endringer i skipsaktivitet og forurensing. Vi analyserer resultatene for to tidshorisonter - nær fremtid (2040-2050) og fjern fremtid (2090-2100) - og for to ulike utslippsscenarioer: ett med moderate fremtidige klimagassutslipp (SSP2-4,5) og ett med høye utslipp (SSP5-8,5). Resultatene viser at fremtidens Barentshavet vil bli varmere, mindre isdekket, surere og mer produktivt, og at fiskebestander og gyteområder vil flytte seg nordover. Det er små forskjeller i de gjennomsnittlige fysiske og biogeokjemiske projeksjonene fra flere modeller mellom de to utslippsscenariene innen 2050, mens det er store forskjeller mellom scenariene mot slutten av århundret. Disse resultatene har vidtrekkende konsekvenser, blant annet ved at de kan identifisere økosystemenes følsomhet for fremtidige utslipp, gi informasjon om regionale forvaltningsstrategier og potensielt identifisere behov for tilpasning til endringer som sannsynligvis allerede vil inntreffe.

• Durant, Joël; Dupont, Nicolas; Ono, Kotaro & Langangen, Øystein Ole Gahr (2024). Interaction between three key species in the sea ice-reduced Arctic Barents Sea system. Proceedings of the Royal Society of London. Biological Sciences. ISSN 0962-8452. 291(2032). doi: 10.1098/rspb.2024.1408. Full text in Research Archive Show summary

  Population dynamics depend on trophic interactions that are affected by climate change. The rise in sea temperature is associated with the disappearance of sea ice in the Arctic. In the Arctic part of the Barents Sea, Atlantic cod, capelin and polar cod are three fish populations that interact and are confronted with climate-induced sea ice reductions. The first is a major predator in the system, while the last two are key species in Arctic and sub-Arctic ecosystems, respectively. There are still many unknowns regarding how predicted environmental change may influence the joint dynamics of these populations. Using time series from a 32 yearlong survey, we developed a state-space model that jointly modelled the dynamics of cod, capelin and polar cod. Using a hindcast scenario approach, we projected the effect of reduced sea ice on these populations. We show that the impact of sea ice reduction and concomitant sea temperature increase may lead to a decrease of polar cod abundance at the benefit of capelin but n

• Olsen, Tora; Stige, Leif Christian; Dupont, Nicolas; Durant, Joël & Langangen, Øystein Ole Gahr (2024). Repeated large declines in the Barents Sea capelin population are associated with different ecosystem conditions. ICES Journal of Marine Science. ISSN 1054-3139. 81(8), p. 1584–1593. doi: 10.1093/icesjms/fsae101. Full text in Research Archive Show summary

  Although fluctuations in the biomass of small pelagic fish are strong and rapid, they are largely investigated as individual events or generalized to what is common across several species and populations. The Barents Sea capelin population, which experienced four large decreases in biomass between 1980 and 2016, can be used to compare the similarity of causes and sequence of events leading up to large biomass decline in the same population. Here, we used an age-structured state-space model to investigate the possible contributions from somatic growth, food availability, temperature, predation by Atlantic cod, herring interactions, and/or fisheries on the capelin biomass declines. We recalculated total biomass while perturbing these effects and assessed the change in total biomass. We did not find a single, common cause for the dramatic biomass declines. Although median biomass increased in several of the scenarios, a large decline in total biomass was mostly retained. Atlantic cod predation and food availability influenced adult capelin biomass. Food availability mainly impacted the first period, while the importance of Atlantic cod predation increased from the first period to the third period. Reducing larval mortality from herring interactions or temperature did not suppress the biomass declines. Recruitment failures were maintained due to a combination of process errors and uncertainty in the effect of spawning biomass, and thus fisheries, on age 0 abundance. The impact of each perturbation depended on the specific ecosystem context at the time of the biomass decline.

• Dupont, Nicolas; Durant, Joël; Langangen, Øystein Ole Gahr & Stige, Leif Christian (2024). Changes in prey-predator interactions in an Arctic food web under climate change. Progress in Oceanography. ISSN 0079-6611. 229, p. 1–16. doi: 10.1016/j.pocean.2024.103380. Full text in Research Archive Show summary

  Global warming affects marine ecosystems by changing environmental conditions, ecosystem structure, and ecosystem functioning. In parts of the Arctic, increased sea temperature and decreased sea ice have led to a poleward expansion of boreal species and increased their interactions with native Arctic species. To investigate and quantify the changing interactions in an Arctic marine food web under new environmental conditions, we studied the interactions between key prey fish species in the seasonally ice-covered parts of the Barents Sea: adult polar cod (Boreogadus saida) and capelin (Mallotus villosus) and one of the major predators in the system: Atlantic cod (Gadus morhua). For this, we compared the predictive performance of threshold models predicting the abundance of adult polar cod as a function of Atlantic cod. Each model was associated with a hypothesis describing prey-predator interactions in different environmental conditions defined by threshold values of summer sea-ice or capelin stock biomass. The best predictive model showed that the predation effect of Atlantic cod on polar cod was strongest in years of low summer sea ice cover and low capelin stock biomass. Our results exemplified that Arctic species such as polar cod may experience increased predation pressure under climate change from boreal species such as Atlantic cod. These effects depend, however, not only on changes in abiotic drivers of species distributions, but also on food-web interactions involving mid-trophic level species such as capelin.

• Geoffroy, Maxime; Bouchard, Caroline; Flores, Hauke; Robert, Dominique; Gjøsæter, Harald & Hoover, Carie [Show all 40 contributors for this article] (2023). The circumpolar impacts of climate change and anthropogenic stressors on Arctic cod (Boreogadus saida) and its ecosystem. Elementa: Science of the Anthropocene. 11(1). doi: 10.1525/elementa.2022.00097. Full text in Research Archive Show summary

  Arctic cod biomass are predicted. In most Arctic seas, the relative abundance of Arctic cod within the fish community will likely fluctuate in accordance with cold and warm periods. A reduced abundance of Arctic cod will negatively affect the abundance, distribution, and physiological condition of certain predators, whereas some predators will successfully adapt to a more boreal diet. Regional management measures that recognize thecritical roleof Arcticcod arerequiredtoensure that increased anthropogenic activities do not exacerbate the impacts of climate change on Arctic marine ecosystems. Ultimately, the mitigation of habitat loss for Arctic cod will only be achieved through a global reduction in carbon emissions.

• Dupont, Nicolas; Vikebø, Frode Bendiksen & Langangen, Øystein Ole Gahr (2022). Assessing the patchiness of early life stage of a fish stock (Gadus morhua) and its contribution to the stock recruitment. Frontiers in Marine Science. 9, p. 1–10. doi: 10.3389/fmars.2022.932169. Full text in Research Archive Show summary

  Patchiness, defined as spatial heterogeneity in distribution of organisms, is a common phenomenon in zooplankton including ichtyoplankton. In heterogeneous landscapes, depending on the scale of prey and predatory distributions, individuals in patches may experience distinct differences in the survival rate compared to individuals distributed more homogeneously outside patches. In this study, we focused on drifting eggs and larvae of Northeast Arctic (NEA) cod, one of the largest exploited fish stock in the world. The eggs and larvae are largely distributed along the north-western coast of Norway and northern Russia. We ask to what degree individuals are located in patches contribute to the species recruitment. For this purpose, we developed a patch recognition method to detect the existence of patches in particle tracking simulations using a connected-component labeling algorithm. We then assessed the contribution of individuals in detected patches to the total recruitment. Our results showed that depending on year, day of year, and resolution scale for detection of patches, recruits present in patches can vary between 0.6% and 38.7% with an average of 20.4% of total recruitment. The percentage decreased with increasing day of year in the drifting season but increased with decreasing patch resolution scale, down to the finest investigated scale of 8 km. On the basis of these results, we advise field recruitment studies of NEA cod to at least resolve an 8-km spatial scale to capture effects of spatial heterogeneity in the survival rate on the species recruitment.

• Dupont, Nicolas; Durant, Joël; Gjøsæter, Harald; Langangen, Øystein Ole Gahr & Stige, Leif Christian (2021). Effects of sea ice cover, temperature and predation on the stock dynamics of the key Arctic fish species polar cod Boreogadus saida. Marine Ecology Progress Series. ISSN 0171-8630. 677, p. 141–159. doi: 10.3354/meps13878. Full text in Research Archive Show summary

  Climate change has large effects on population dynamics of fish species in high latitude ecosystems. Arctic fish stocks experience multiple pressures with changing abiotic living conditions and increased competition and predation from boreal species. However, there are many unknowns regarding how environmental change influences the dynamics of those populations. Here, we focused on the Barents Sea polar cod, a pan-Arctic zooplanktivorous key fish species physiologically and ecologically adapted to the presence of sea ice. We developed an age-resolved Bayesian state-space model of the dynamics of polar cod based on 30 yr of survey data (1986-2015). Using this model, we quantified how inter-annual changes in abundance were associated with abiotic variables (temperature and sea ice cover) and biotic variables (prey biomasses and a predation index). Using the model output, we used a hindcast scenario approach to investigate to which degree the observed variations in total population size were related to the abiotic or biotic variables. Our results showed that variation in abundance of young polar cod (ages 0 and 1) was best explained by abiotic variables while variation in the older age groups (ages 3 and 4) was best explained by predation. Hindcast scenarios showed that the abiotic variables had a more evident effect than predation on population dynamics, but none of the variables we considered could explain the drastic population decline observed in recent years. Our work shows the advantages of studying age-specific responses as a stepping stone to understand changes at the population level.

• Dupont, Nicolas; Durant, Joel Marcel; Langangen, Øystein; Gjøsæter, Harald & Stige, Leif Christian (2020). Sea ice, temperature, and prey effects on annual variations in mean lengths of a key Arctic fish, Boreogadus saida, in the Barents Sea. ICES Journal of Marine Science. ISSN 1054-3139. 77(5), p. 1796–1805. doi: 10.1093/icesjms/fsaa040. Full text in Research Archive Show summary

  Oceanographic conditions in the Arctic are changing, with sea ice cover decreasing and sea temperatures increasing. Our understanding of the effects on marine populations in the area is, however, limited. Here, we focus on the Barents Sea stock of polar cod (Boreogadus saida). Polar cod is a key fish species for the transfer of energy from zooplankton to higher trophic levels in the Arctic food web. We analyse the relationships between 30-year data series on the length-at-age of polar cod cohorts (ages 0–4) and sea surface temperature, sea ice concentration, prey biomasses, predator indices, and length-at-age the previous year using multiple linear regression. Results for several ages showed that high length-at-age is significantly associated with low sea ice concentration and high length-at-age the previous year. Only length-at-age for age 1 shows a positive significant relationship with prey biomass. Our results suggest that retreating sea ice has positive effects on the growth of polar cod in the Barents Sea despite previous observations of a stagnating stock biomass and decreasing stock abundance. Our results contribute to identifying mechanisms by which climate variability affects the polar cod population, with implications for our understanding of how future climate change may affect Arctic ecosystems.

• Melle, Webjørn Raunsgård; Klevjer, Thor A.; Drinkwater, Kenneth F.; Strand, Espen; Naustvoll, Lars Johan & Wiebe, Peter H. [Show all 14 contributors for this article] (2020). Structure and functioning of four North Atlantic ecosystems - A comparative study. Deep-Sea Research Part II: Topical Studies in Oceanography. ISSN 0967-0645. 180, p. 1–13. doi: 10.1016/j.dsr2.2020.104838. Full text in Research Archive Show summary

  The epi- and mesopelagic ecosystems of four sub-polar ocean basins, the Labrador, Irminger, Iceland and Norwegian seas, were surveyed during two legs from Bergen, Norway, to Nuuk, Greenland, and back to Bergen. The survey was conducted from 1 May to 14 June, and major results were published in five papers (Drinkwater et al., Naustvoll et al., Strand et al., Melle et al., this issue, and Klevjer et al., this issue a, this issue b). In the present paper, the structures of the ecosystem are reviewed, and aspects of the functioning of the ecosystems examined, focusing on a comparison of trophic relationships in the four basins. In many ways, the ecosystems are similar, which is not surprising since they are located at similar latitudes and share many hydrographic characteristics, like input of both warm and saline Atlantic water, as well as cold and less saline Arctic water. Literature review suggests that total annual primary production is intermediate in the eastern basins and peaks in the Labrador Sea, while the Irminger Sea is the most oligotrophic sea. This was not reflected in the measurements of different trophic levels taken during the cruise. The potential new production was estimated to be higher in the Irminger Sea than in the eastern basins, and while the biomass of mesozooplankton was similar across basins, the biomass of mesopelagic micronekton was about one order of magnitude higher in the western basins, and peaked in the Irminger Sea, where literature suggests annual primary production is at its lowest. The eastern basins hold huge stocks of pelagic planktivore fish stocks like herring, mackerel and blue whiting, none of which are abundant in the western seas. As both epipelagic nekton and mesopelagic micronekton primarily feed on the mesozooplankton, there is likely competitive interactions between the epipelagic and mesopelagic, but we're currently unable to explain the estimated ~1 order of magnitude difference in micronekton standing stock. The results obtained during the survey highlight that even if some aspects of pelagic ecosystems are well understood, we currently do not understand overall pelagic energy flow in the North Atlantic.

• Klevjer, Thor A.; Melle, Webjørn Raunsgård; Knutsen, Tor; Strand, Espen; Korneliussen, Rolf & Dupont, Nicolas [Show all 8 contributors for this article] (2019). Micronekton biomass distribution, improved estimates across four north Atlantic basins. Deep-Sea Research Part II: Topical Studies in Oceanography. ISSN 0967-0645. p. 1–11. doi: 10.1016/j.dsr2.2019.104691. Full text in Research Archive Show summary

  Distribution of micronekton was investigated during early summer of 2013, using data from a cruise covering the central parts of four north Atlantic basins, the Norwegian Sea (NS), Iceland Sea (ICS), Irminger Sea (IRS), and Labrador Sea (LS). Continuous underway acoustics mapped vertical and horizontal distributions, and trawl sampling provided data on biomass and taxonomic composition. The hull mounted acoustics and trawl catches suggested that, among the four basins, biomass of epipelagic, larger nektonic species (>20 cm length) during the cruise was highest in the NS and ICS basins, while mesopelagic non-gelatinous micronekton biomass peaked in the IRS and LS basins. Biomass of Scyphozoa was also about 1 order of magnitude higher in IRS and LS compared to ICS and NS. In ICS and NS, crustaceans made up about 50% of total non-gelatinous micronekton biomass, with fish making up less than 20% of total biomass. In contrast, fish constituted more than 60% of non-gelatinous biomass of catches in IRS and LS. In catches from ICS and NS the myctophid Benthosema glaciale dominated the catches, whereas bathylagids, gonostomatids, barracudinas and stomiids contributed to the high biomass densities of fish in IRS and LS. In addition to the differences in biomass between the basins, the acoustic measurements suggested gradients within the north-eastern basins, and large differences in vertical distribution of biomass between the basins during the cruise.

• Dupont, Nicolas; Bagøien, Espen & Melle, Webjørn Raunsgård (2017). Inter-annual variability in spring abundance of adult Calanus finmarchicus from the overwintering population in the southeastern Norwegian Sea. Progress in Oceanography. ISSN 0079-6611. 152, p. 75–85. doi: 10.1016/j.pocean.2017.02.004. Full text in Research Archive
• Dupont, Nicolas & Aksnes, Dag Lorents (2013). Centennial changes in water clarity of the Baltic Sea and the North Sea. Estuarine, Coastal and Shelf Science. ISSN 0272-7714. 131, p. 282–289. doi: 10.1016/j.ecss.2013.08.010. Full text in Research Archive Show summary

  Secchi depth is a valuable proxy for detecting long term changes in the water clarity of oceanic and coastal ecosystems. We analyse approximately 40 000 observations, which are available from ICES, from the Baltic Sea and the North Sea in the 20th century. Our results suggest pronounced effects of bottom depth and distance to coast on Secchi depth, and we account for this topographical effect in an assessment of the long term change in water clarity. Our results suggest a centennial Secchi depth shoaling of 3.2 ± 0.2 and 5.8 ± 0.6 m in areas that are shallower and deeper than 100 m in the Baltic Sea. For the North Sea the corresponding numbers were 1.8 ± 0.3 and 5.2 ± 0.9 m. We discuss potential ecosystem effects involving pronounced reductions in photic habitats and reduced visibility for visual predators. We suggest that the role of long term variations in colour dissolved organic matter (CDOM) on the transparency in the Baltic Sea and North Sea deserves future attention.

• Urtizberea, Agurtzane; Dupont, Nicolas; Rosland, Rune & Aksnes, Dag Lorents (2013). Sensitivity of euphotic zone properties to CDOM variations in marine ecosystem models. Ecological Modelling. ISSN 0304-3800. 256, p. 16–22. doi: 10.1016/j.ecolmodel.2013.02.010. Full text in Research Archive Show summary

  In marine ecosystem models, the underwater light intensity is commonly characterized by the shading of phytoplankton in addition to a background light attenuation coefficient. Colour dissolved organic matter (CDOM) is an important component of the background light attenuation, and we investigate how variation in CDOM attenuation affects euphotic zone properties in a general marine ecosystem model. Our results suggest that euphotic zone properties are highly sensitive to CDOM variations occurring in nature. While the nutrient input to the euphotic zone scales the magnitude of the primary production, the vertical structure of nutrients and phytoplankton is largely determined by the variation in CDOM attenuation in our simulations. This suggests that knowledge of CDOM variation is useful to constrain uncertainties in predictions of water column structure in marine ecosystem modelling, but also in analyses utilizing the oceanic nutricline depth as proxy for primary production. Finally, according to our sensitivity analysis, many coastal areas experiencing high loads of terrestrial CDOM are expected to show eutrophication symptoms induced by altered optics.

• Dupont, Nicolas & Aksnes, Dag Lorents (2012). Effects of bottom depth and water clarity on the vertical distribution of Calanus spp. Journal of Plankton Research. ISSN 0142-7873. 34(3), p. 263–266. doi: 10.1093/plankt/fbr096. Full text in Research Archive
• Dupont, Nicolas & Aksnes, Dag Lorents (2010). Simulation of optically conditioned retention and mass occurrences of Periphylla periphylla. Journal of Plankton Research. ISSN 0142-7873. 32(6), p. 773–783. doi: 10.1093/plankt/fbq015. Full text in Research Archive
• Dupont, Nicolas; Klevjer, Thor A.; Kaartvedt, Stein & Aksnes, Dag Lorents (2009). Diel vertical migration of the deep-water jellyfish Periphylla periphylla simulated as individual responses to absolute light intensity. Limnology and Oceanography. ISSN 0024-3590. 54(5), p. 1765–1775. Full text in Research Archive
• Aksnes, Dag Lorents; Dupont, Nicolas; Staby, Arved; Fiksen, Øyvind; Kaartvedt, Stein & Aure, Jan (2009). Coastal water darkening and implications for mesopelagic regime shifts in Norwegian fjords. Marine Ecology Progress Series. ISSN 0171-8630. 387, p. 39–49. doi: 10.3354/meps08120. Full text in Research Archive Show summary

  The light regime of the water column has a strong structuring effect on aquatic food webs and it has been previously hypothesized that coastal water darkening has increased the success of tactile predators relative to visual predators such as fish. Due to a general lack of time-series of optical parameters, we applied a proxy for light attenuation that depends on salinity and dissolved oxygen at a time of the year when chlorophyll concentrations were low. We present evidence that coastal waters of Norway have darkened as a result of freshening over the period 1935 to 2007. Our results suggest that locations where coastal water penetrates into deep basins have been prone to water column darkening, particularly if dissolved oxygen has also declined. We have estimated that salinity and oxygen variation on the ranges 33 to 35 PSU and 1 to 6 ml O2 l–1 are associated with up to 8 orders of magnitude difference in photon flux at 200 m depth in a water column devoid of pigments. Our results suggest such darkening needs to be considered in analyses of mesopelagic regime shifts involving mass occurrence of the jellyfish Periphylla periphylla.

View all works in NVA

• Giebichenstein, Julia; Dupont, Nicolas; Harju, Mikael; Varpe, Øystein; Gabrielsen, Geir W. & Andersen, Tom [Show all 7 contributors for this article] (2025). Seasonal Insights into Pollutant Accumulation and Biomagnification in an Arctic Marine Food Web. Full text in Research Archive
• Dupont, Nicolas; Durant, Joël; Langangen, Øystein Ole Gahr & Stige, Leif Christian (2023). Survival of adult polar cod (Boreogadus saida) in the context of “borealization” of the Barents Sea. Full text in Research Archive
• Dupont, Nicolas; Durant, Joël; Langangen, Øystein Ole Gahr & Stige, Leif Christian (2023). Effects of abrupt ecological change on the Barents Sea Arctic food-web: predictions from a food-web state-space model. Full text in Research Archive
• Dupont, Nicolas; Durant, Joël; Langangen, Øystein Ole Gahr & Stige, Leif Christian (2022). Change in the Barents Sea Arctic food-web dynamic based on biotic and abiotic environmental factors. Full text in Research Archive
• Dupont, Nicolas (2021). What happens with the Arctic ecosystem when the sea-ice disappears? Full text in Research Archive
• Dupont, Nicolas; Durant, Joël; Gjøsæter, Harald; Langangen, Øystein Ole Gahr & Stige, Leif Christian (2021). Using time series to predict the future: quantifying the effects of borealization on polar cod (Boreogadus saida). Full text in Research Archive
• Dupont, Nicolas (2021). Fishes in the Arctic: the example of polar cod. Full text in Research Archive
• Dupont, Nicolas (2021). Borealization of the Barents Sea : effect on the polar cod stock. Full text in Research Archive
• Dupont, Nicolas; Durant, Joel Marcel; Langangen, Øystein; Gjøsæter, Harald & Stige, Leif Christian (2019). Environmental effects on population annual mean length of polar cod (Boreogadus saida) in the Barents Sea. Full text in Research Archive
• Dupont, Nicolas; Durant, Joel Marcel; Langangen, Øystein; Gjøsæter, Harald & Stige, Leif Christian (2019). Environmental effects on population annual mean length of polar cod (Boreogadus saida) in the Barents Sea. Full text in Research Archive
• Stige, Leif Christian; Kløver, Geir Olav; Dupont, Nicolas; Borgå, Katrine; Stenseth, Nils Christian & Isachsen, Pål Erik [Show all 7 contributors for this article] (2019). Kunnskap fra isødet. Full text in Research Archive Show summary

  Åpent arrangement med disse foredragene: "Kunnskapsinnhøsting i Arktis ombord i Fram 1893-1896" (Kløver); "Arven etter Nansen" (Stige); "Hva skjer med økosystemet når sjøisen forsvinner?" (Dupont); "Miljøgifter i Arktis" (Borgå); "Havstrømmene i Arktis – hvorfor er de spesielle?" (Isachsen); "En djerv polarforsker: Hanna Resvoll-Holmsen (1873-1943)" (Sandberg). Ordstyrere: Stige og Stenseth.

• Dupont, Nicolas; Stige, Leif Christian & Langangen, Øystein (2017). Effects of heterogeneous spatial mortality on recruitment of Northeast Arctic cod (Gadus morhua) in the Barents Sea. Full text in Research Archive
• Durant, Joel Marcel; Langangen, Øystein & Dupont, Nicolas (2017). Barents Sea cod larvae survival and match-mismatch. Full text in Research Archive
• Dupont, Nicolas; Stige, Leif Christian; Bagøien, Espen & Melle, Webjørn Raunsgård (2016). Long-term trends and seasonal patterns for Calanus finmarchicus and Calanus helgolandicus in the Coastal Water off southwest Norway during 1996-2012. Full text in Research Archive
• Dupont, Nicolas; Bagøien, Espen & Melle, Webjørn Raunsgård (2016). Long-term trends and variability in spring development of Calanus finmarchicus in the southeastern Norwegian Sea during 1996-2012. Full text in Research Archive
• Steen, Henning; Kartveit, Kyrre Heldal; Dupont, Nicolas & Norderhaug, Kjell Magnus (2025). Tareundersøkelser i Nordland 2020-24 |. Havforskningsinstituttet. Full text in Research Archive Show summary

  Havforskningsinstituttet har i perioden 2020-24 gjennomført undersøkelser av taresamfunn på kyststrekningen Bindal (65° 13’ N) – Vega (65° 33’ N) i Nordland. Deler av denne kyststrekningen ble åpnet for kommersiell høsting av stortare (Laminaria hyperborea) i 2022, etter en prøvehøstingsperiode i 2013-17. Effekter av den tidligere prøvehøstingen på taresamfunn og kråkebolleforekomster ble undersøkt ved hjelp av undervannsvideo langs transekter og innsamlinger av tareplanter på utvalgte stasjoner for studier av morfologi, alder, assosiert biomangfold (epifyttsamfunn) og kråkebollerekruttering. Resultatene fra disse undersøkelsene indikerer at stortarevegetasjonens størrelse og biomasse er reetablert 5 år etter høsting, mens begroingssamfunnene (epifyttene) knyttet til tarestilkene er reetablert 8 år etter høsting og da lik tilsvarende observert i uhøstede referanseområder. Resultatene tyder på at forekomstene av kråkeboller er på et moderat nivå og at reetableringen av tare på høstefeltene ikke har vært hemmet av kråkebollebeiting.

• Fuhrmann, Mona Maria; Kutti, Tina; Dupont, Nicolas & Dunlop, Katherine Mary (2025). Sårbar, verdifull og karakteristisk natur i Tysfjorden. Havforskningsinstituttet. Full text in Research Archive Show summary

  Havforskningsinstituttet har gjennomført ny kartlegging av bunndyrssamfunn i Tysfjorden og kombinert denne med allerede eksisterende informasjon om bunndyrssamfunn på forskjellige plasser i fjorden. Dette for å få en oversikt over hvor man kan forvente å finne sårbar, verdifull og karakteristisk natur, som støtte til planarbeidet med utredning av Tysfjorden marine verneområde. Kartleggingsarbeidet avdekket et rikt artsmangfold på bunndyp mellom 60 og 620 meter. Totalt ble 137 taksa, fra mange forskjellige dyregrupper registrert. Svamper og nesledyr (koraller) var de mest vanlig forekommende dyregruppene, etterfulgt av bløtdyr, leddyr og pigghuder. Syv rødlistede arter ble observert. Flere av dem, som bambuskorallen Isidella lofotensis, var relativt vanlig. På 31 av de 55 undersøkte stasjonene ble minst en rødlistet art observert og sammen ble over 2000 individ av rødlistete arter registrert. Rødlistede naturtyper ble observert frem for alt på veldig bratte fjordvegger og terskelområder, samt i de dype fjordbassengene. Bambuskorallskoger med uvanlig høy tetthet, ble funnet i de dype bassengene midt i Tysfjorden og ytterst i Hellmofjorden og prediksjonsmodellering viser at slike bambuskorallskoger kan forekommer over store deler av de dype fjordbassengene, både i ytre og midtre deler av fjorden. Korallrev av øyekorall ble dokumentert som veggrev på bratte fjellvegger i den ytre delen av fjorden, i områder med sterk bunnstrøm. Risengryskoraller bygget korallskoger i helninger og på ruglete bunn i midten av Tysfjorden. Svampeskoger på bløtt og hardt substrat (ansett som forvaltningsrelevant, men ikke rødlistet som naturtyper i Norge) forekom både i indre og ytre deler av fjorden. Reirskjellsamfunn ble dokumentert på bratte fjellvegger over hele fjordsystemet. Det generelle inntrykket etter kartleggingen er at den dype Tysfjorden huser et mangfold av sårbar natur, med rikelige forekomster av korallrev, korallskoger og svamp- og sjøfjærhager. Særlig korallskogene bygget av bambuskoraller i de dype bassengene over store deler av fjorden, er uvanlig vidstrakte, tette og uforstyrrete sammenlignet med det vi kjenner fra andre fjorder. Fjorden fremstår med dette unik og bør forvaltes med omhu.

• Dupont, Nicolas (2010). Water clarity as a forcing factor of marine ecosystems. Universitetet i Bergen. Full text in Research Archive

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