Variations in liver and body condition during gonad development of Atlantic halibut, Hippoglossus hippoglossus (L.)

Data were collected from Atlantic halibut (Hippoglossus hippoglossus) caught in gill nets and on long lines in northern Norway between September and March during the years 1981-1986. The liver is significantly depleted during the spawning season, thus indicating that it is an important energy source for the halibut in this period. The carcass seems less affected by the energy expenditures involved in the seasonal accumulation of reproductive tissues and in spawning, particulary in females where no significant sacrifice of body weight was observed

Grønlandssel

The Northeast Atlantic stocks of harp seals are commercially exploited by Norway and Russia. The stocks are assessed every second year by the Joint ICES/NAFO Working Group on Harp and Hooded Seals. The assessments are based on modelling, which provides ICES with sufficient information to give advice on both status and catch potential for the stocks

Field trial performance of Norway spruce families from Opsahl Seed Orchard

Field trials with Norway spruce seedlings from 84 full-sib families from a factorial cross in Opsahl Seed Orchard and 11 provenances were planted at eight sites between altitudes between 600 and 900 m in Oppland County in Norway. Measurements of tree heights and assessments of stem and branch defects were made at regular intervals until 34 years from seed. Data from measurements made in nursery trials and from artificial freezing trials were also available. The families from the seed orchard had on average 12 % better height growth than the provenances. For volume growth per hectare, measured in two of the trials 30 years after planting, the families had a superiority of more than 30 %. A large variation among families was present for height growth and additive genetic variation was the main genetic factor. For the maternal half-sib families, the ranking of families for height was stable after 15 years from seed, and the five best families selected for height at that age were at age 34 years 6 % taller and produced 13 % more volume per hectare compared with the mean of all families. Weak relationships were present between traits measured in the nursery trial, the freezing test and the field trials. Assessments were made of cone production at age 20 years after planting and showed variation among families for the frequency of trees with cones.Field trial performance of Norway spruce families from Opsahl Seed OrchardpublishedVersio

Harp Seals: Monitors of Change in Differing Ecosystems

Harp seals are the most abundant marine mammal in the north Atlantic. As an ice obligatory predator, they reflect changes in their environment, particularly during a period of climatic change. As the focus of a commercial hunt, a large historic data set exists that can be used to quantify changes. There are three populations of harp seals: White Sea/Barents Sea, Greenland Sea and Northwest Atlantic. The objective of this paper is to review their current status and to identify the factors that are influencing population dynamics in different areas. Although important historically, recent catches have been low and do not appear to be influencing trends in either of the two northeast Atlantic populations. Massive mortalities of White Sea/Barents Sea seals occurred during the mid 1980s due to collapses in their main prey species. Between 2004 and 2006, pup production in this population declined by 2/3 and has remained low. Body condition declined during the same period, suggesting that ecosystem changes may have resulted in reduced reproductive rates, possibly due to reduced prey availability and/or competition with Atlantic cod. The most recent estimate of pup production in the Greenland Sea also suggests a possible decline during a period of reduced hunting although the trend in this population is unclear. Pupping concentrations are closer to the Greenland coast due to the reduction in ice in the traditional area and increased drift may result in young being displaced from their traditional feeding grounds leading to increased mortality. Reduced ice extent and thickness has resulted in major mortality of young in the Northwest Atlantic population in some years. After a period of increase, the population remained relatively stable between 1996 and 2013 due to increased hunting, multiple years with increased ice-related mortality of young seals, and lower reproductive rates. With a reduction in harvest and improved survival of young, the population appears to be increasing although extremely large interannual variations in body condition and fecundity have been observed which were found to be influenced by variations in capelin biomass and ice conditions. Each of these populations has been impacted differently by changes in their ecosystems and hunting practices. By identifying the factors influencing these three populations, we can gain a better understanding of how species may respond to changes that are occurring in their ecosystems.publishedVersio

Studies of minke whale (Balaenoptera acutorostrata) ecology in the northeast Atlantic: Preliminary results from studies of diet and food availability during summer 1992

Stomach content samples from 92 minke whales Balaenoptera acutorostrata, caught during scientific whaling operations in July-August 1992, were collected in five selected areas in Norwegian and adjacent waters. Preliminary results from the stomach analyses indicate a diet almost completely dominated by fish, although there was considerable heterogeneity in species composition between the areas. Capelin dominated the minke whale diets in the two northernmost study areas (Spitsbergen and Bear Island). Further south, in coastal areas of North Norway and Russia, herring was the most important food item, but was accompanied by significant amounts of sand eel, cod, haddock and saithe. A survey aimed to locate and classify fish and plankton resources was conducted simultaneously with the scientific whaling program. The northern areas were particularly dominated by 0-group cod (which was not found in whale stomachs), while capelin abundance was recorded only sporadically. Along the coast of North Norway and Russia, there appeared to be a larger degree of similarity between prey abundance and minke whale diet. Herring was documented to be very abundant both in the resource surveys and in the whale stomach analyses. The similarity in distribution was particularly conspicuous for 0-group herring

Nutrient concentrations in minke whale faeces and the potential impact on dissolved nutrient pools off Svalbard, Norway

There is increasing interest in assessing the impact of whales on nutrient and carbon cycling in the ocean. By fertilising surface waters with nutrient-rich faeces, whales may stimulate primary production and thus carbon uptake, but robust assessments of such effects are lacking. Based on the analysis of faeces collected from minke whales (n = 31) off Svalbard, Norway, this study quantified the concentration of macro and micronutrients in whale faeces prior to their release in seawater. Concentrations of the macronutrients nitrogen (N) and phosphorous (P) in minke whale faeces were 50.1 ± 10.3 and 70.9 ± 12.1 g kg−1 dry weight, respectively, while the most important micronutrients were zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu). By combining measured faecal nutrient concentrations with estimated prey-consumption and prey-assimilation rates, we calculate that the current population of approximately 15, 000 individuals in the small management area (SMA) of Svalbard defecates daily 7 ± 1.4 tonnes (t) N and 10 ± 1.7 t P during summer. The molar ratio of N:P in minke whale faeces was 1.6:1, meaning that N was proportionally limiting, when compared to average elemental ratios of 16:1 in phytoplankton. In case of no N limitation in surface waters at that time, the release of elemental P through defecation in surface waters has the potential to stimulate 407 ± 70 t of carbon per day during summer as new or regenerated primary production in the SMA of Svalbard. This amounts to 0.2 to 4 % of daily net primary production in this region. This study provides the first assessment of nutrient concentration in whale faeces prior to their dissolution in sea water. Further research, namely on the amount of N released via urine and seasonal changes in excreted nutrients, is needed to better assess the full potential of whale nutrient additions to dissolved nutrient pools in surface waters at regional and global scales.publishedVersio

Emerging and legacy contaminants in common minke whale from the Barents sea

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Recent age compositions and aberrant migration patterns of the Barents Sea stock of harp seals Phoca groenlandica

Since 1978, and in particular in 1986-1988, large numbers of harp seals Phoca groenlandica have invaded coastal waters of North Norway during winter and spring. After 1988 the harp seal invasions have been restricted to the northeastemmost parts of the coast of Norway. In 1995, however, a significant increase occurred in both the magnitude and the spatial extent of the harp seal invasions. Sampling of stomach contents, teeth for age determinations and body condition parameters were carried out on seals taken as by-catches in Norwegian gillnet fisheries during winter and spring in 1995. In early winter the seal herds comprised immature animals (mainly from the 1994 year class), while mature females dominated in the spring. Analyses of stomach contents suggested that the diet mainly contained fish, in particular saithe Pollachius virens, haddock Melanogrammus aeglefinus and cod Gadus morhua. Body condition parameters revealed that the one year old seals taken in February 1995 were in significantly poorer condition than harp seals of the same age taken in the southeastem Barents Sea in February 1993. Also the mature females taken in April 1995 had significantly lower condition compared to adult females collected in April 1992. Recaptures of 39 immature harp seals tagged in the White Sea (mainly in 1994) suggest that the invading young harp seals in the winter of 1995 belonged to the Barents Sea stock. Age compositions of the Barents Sea harp seals based on material collected during Norwegian commercial sealing in the East Ice moulting lairs in 1995 suggest a low recruitment to this stock of the 1993 and in particular the 1994 year classes

Linking an Early Triassic delta to antecedent topography: Source-to-sink study of the southwestern Barents Sea margin

Present-day catchments adjacent to sedimentary basins may preserve geomorphic elements that have been active through long intervals of time. Relicts of ancient catchments in present-day landscapes may be investigated using mass-balance models and can give important information about upland landscape evolution and reservoir distribution in adjacent basins. However, such methods are in their infancy and are often difficult to apply in deep-time settings due to later landscape modification. The southern Barents Sea margin of N Norway and NW Russia is ideal for investigating source-to-sink models, because it has been subject to minor tectonic activity since the Carboniferous, and large parts have eluded significant Quaternary glacial erosion. A zone close to the present-day coast has likely acted as the boundary between basin and catchments since the Carboniferous. Around the Permian-Triassic transition, a large delta system started to prograde from the same area as the present-day largest river in the area, the Tana River, which has long been interpreted to show features indicating that it was developed prior to present-day topography. We performed a source-to-sink study of this ancient system in order to investigate potential linkages between present-day geomorphology and ancient deposits. We investigated the sediment load of the ancient delta using well, core, two-dimensional and three-dimensional seismic data, and digital elevation models to investigate the geomorphology of the onshore catchment and surrounding areas. Our results imply that the present-day Tana catchment was formed close to the Permian-Triassic transition, and that the Triassic delta system has much better reservoir properties compared to the rest of Triassic basin infill. This implies that landscapes may indeed preserve catchment geometries for extended periods of time, and it demonstrates that source-to-sink techniques can be instrumental in predicting the extent and quality of subsurface reservoirs.publishedVersio

Good ethics or political and cultural censoring in science?

Peer-reviewed journals are the cornerstones to communicating scientific results. They play a crucial role in quality assurance through the review process, but they also create opportunities for discussions in the scientific community on the implications of the results or validation of methods and data. This requires that journals adhere to commonly accepted scientific standards and are open about their editorial policy. Norwegian scientists experience problems in getting research on minke whales accepted for publication where the data have been collected in association with commercial whaling. The journal Biology Letters refuses to publish papers based on data from the Norwegian whale register while publically claiming a sole focus on scientific quality. Although there are good arguments for claiming that clearly unethical research should not be rewarded with scientific publications, one also has to realize that some fields of research are beset with unresolved ethical and cultural debates. In these cases, it is to the benefit of the progress of science, and indeed society, to be open about the issues and support arguments through scientific studies. Political or cultural censoring of scientific information will in any case jeopardize the role of journals in quality assurance of scientific research and undermine the credibility of science as a supplier of objective and reliable knowledge.publishedVersio