Pan-Arctic suitable habitat model for Greenland halibut

Deep-sea marine fishes support important fisheries but estimates of their distributions are often incomplete as the data behind them may reflect fishing practices, access rights, or political boundaries, rather than actual geographic distributions. We use a simple suitable habitat model based on bottom depth, temperature, and salinity to estimate the potential distribution of Greenland halibut (Reinhardtius hippoglossoides). A large presence-only dataset is examined using multivariate kernel densities to define environmental envelopes, which we link to spatial distribution using a pan-Arctic oceanographic model. Occurrences generally fit the model well, although there were gaps in the predicted circum-Arctic distribution likely due to limited survey activity in many of the ice-covered seas around the Arctic Ocean. Bottom temperature and depth were major factors defining model fit to observations, but other factors, such as ecosystem interactions and larval drift could also influence distribution. Model predictions can be tested by increasing sampling effort in poorly explored regions and by studying the connectivity of putative populations. While abundances of Greenland halibut in the High Arctic are currently low, some areas are predicted to be suitable habitat for this species, suggesting that on-going sea-ice melt may lead to fisheries expansion into new areas

Phenology and Environmental Control of Phytoplankton Blooms in the Kong Håkon VII Hav in the Southern Ocean

Knowing the magnitude and timing of pelagic primary production is important for ecosystem and carbon sequestration studies, in addition to providing basic understanding of phytoplankton functioning. In this study we use data from an ecosystem cruise to Kong Håkon VII Hav, in the Atlantic sector of the Southern Ocean, in March 2019 and more than two decades of satellite-derived ocean color to study phytoplankton bloom phenology. During the cruise we observed phytoplankton blooms in different bloom phases. By correlating bloom phenology indices (i.e., bloom initiation and end) based on satellite remote sensing to the timing of changes in environmental conditions (i.e., sea ice, light, and mixed layer depth) we studied the environmental factors that seemingly drive phytoplankton blooms in the area. Our results show that blooms mainly take place in January and February, consistent with previous studies that include the area. Sea ice retreat controls the bloom initiation in particular along the coast and the western part of the study area, whereas bloom end is not primarily connected to sea ice advance. Light availability in general is not appearing to control the bloom termination, neither is nutrient availability based on the autumn cruise where we observed non-depleted macronutrient reservoirs in the surface. Instead, we surmise that zooplankton grazing plays a potentially large role to end the bloom, and thus controls its duration. The spatial correlation of the highest bloom magnitude with marked topographic features indicate that the interaction of ocean currents with sea floor topography enhances primary productivity in this area, probably by natural fertilization. Based on the bloom timing and magnitude patterns, we identified five different bloom regimes in the area. A more detailed understanding of the region will help to highlight areas with the highest relevance for the carbon cycle, the marine ecosystem and spatial management. With this gained understanding of bloom phenology, it will also be possible to study potential shifts in bloom timing and associated trophic mismatch caused by environmental changes.publishedVersio

Innspill til høring - Forslag til program for konsekvensutredning for mineralvirksomhet på norsk sokkel

Rapporten er et høringssvar sendt til Olje- og Energidepartementet i forbindelse med et forslag til konsekvensutredningsprogram for mineralvirksomhet på norsk kontinentalsokkel. I høringssvaret påpeker Havforskningsinstituttet at det er stor mangel på kunnskap, både med hensyn til biomangfold og økologiske forhold, men også når det gjelder teknologien som vil anvendes for utvinning av mineraler og metaller på havbunnen. Denne kunnskapsmangelen representerer en usikkerhet som bør synliggjøres i konsekvensutredningen, blant annet gjennom en risikoanalyse. Havforskningsinstituttet påpeker også at ulike initiativ når det gjelder kunnskapsinnhenting burde vært ferdigstilt før gjennomføringen av høringen. En grundigere oppsummering av rapportens innhold er gitt i første kapittel.publishedVersio

Advice on fishing opportunities for Barents Sea capelin in 2024 — ICES subareas 1 and 2 excluding Division 2.a west of 5°W

publishedVersio

Advice on fishing opportunities for Barents Sea capelin in 2024 — ICES subareas 1 and 2 excluding Division 2.a west of 5°W

Source at https://www.hi.no/hi/nettrapporter

First results from the L3+C experiment at CERN

The L3+C experiment combines the high-precision spectrometer of the L3 detector at LEP, CERN, with a small air shower array. The momenta of cosmic ray induced muons can be measured from 20 to 2000 GeV/c. During the 1999 data taking period 5 billion muon events were recorded in the spectrometer. From April until mid Summer 2000 an additional 3 billion muon events have been recorded as well as 25 million air shower events. Here the first results on the muon momentum spectrum and charge ratio will be presented

Predation on early life stages is decisive for year-class strength in the Barents Sea capelin (Mallotus villosus) stock

Year-class strength of Barents Sea capelin has been monitored closely since the early 1970s and during this ∼45 years period three short periods of almost total recruitment failure leading to three stock collapses have been observed. These events triggered much attention since there was a large commercial fishery for capelin, but also because of observed ecosystem effects attributed to the first of these collapse events. This attention motivated research to clarify mechanisms behind the recruitment failures, and many papers have been published regarding the causes of these events. Here, we review this literature and try to put the various investigations into context. Most of the research conducted gives evidence in favour of a hypothesis that was formulated after the first recruitment failure event in the mid-1980s that predation on capelin larvae was the main cause of recruitment failure. Most studies also support the hypothesis that young herring (Clupea harengus) was the main predator on capelin larvae, but other predators like young-of-the-year cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) probably also played a role. Investigations of the effect of predators such as haddock, red king crab (Paralithodes camtschaticus), diving birds, and capelin on the demersal capelin eggs have also been reviewed. Usually, these predators are found to consume capelin eggs, but most likely not to an extent that would affect the recruitment to a noticeable degree. It is concluded that the predation on capelin larvae is the main reason for the observed recruitment failures, although predation from the predators reviewed here can hardly be the only reason for almost total recruitment failures observed in some periods

Innspill til høring - Forslag til program for konsekvensutredning for mineralvirksomhet på norsk sokkel

Rapporten er et høringssvar sendt til Olje- og Energidepartementet i forbindelse med et forslag til konsekvensutredningsprogram for mineralvirksomhet på norsk kontinentalsokkel. I høringssvaret påpeker Havforskningsinstituttet at det er stor mangel på kunnskap, både med hensyn til biomangfold og økologiske forhold, men også når det gjelder teknologien som vil anvendes for utvinning av mineraler og metaller på havbunnen. Denne kunnskapsmangelen representerer en usikkerhet som bør synliggjøres i konsekvensutredningen, blant annet gjennom en risikoanalyse. Havforskningsinstituttet påpeker også at ulike initiativ når det gjelder kunnskapsinnhenting burde vært ferdigstilt før gjennomføringen av høringen. En grundigere oppsummering av rapportens innhold er gitt i første kapittel