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Emerging and legacy contaminants in common minke whale from the Barents sea
Get PDFPersistent organic pollutants (POPs), including brominated flame retardants (BFRs), perfluoroalkyl substances (PFAS) and metals, can accumulate in marine mammals and be transferred to offspring. In this study, we analyzed 64 lipophilic POPs, including four emerging BFRs, in the blubber, liver and muscle of 17 adult common minke whales (Balaenoptera acutorostrata) from the Barents Sea to investigate occurrence and tissue partitioning. In addition, the placental transfer concentration ratios of 14 PFAS and 17 metals were quantified in the muscle of nine female-fetus pairs to investigate placental transfer. Legacy lipophilic POPs were the dominating compound group in every tissue, and we observed generally lower levels compared to previous studies from 1992 to 2001. We detected the emerging BFRs hexabromobenzene (HBB) and pentabromotoluene (PBT), but in low levels compared to the legacy POPs. We detected nine PFAS, and levels of perfluorooctane sulfonate (PFOS) were higher than detected from the same population in 2011, whilst levels of Hg were comparable to 2011. Levels of lipophilic contaminants were higher in blubber compared to muscle and liver on both a wet weight and lipid adjusted basis, but tissue partitioning of the emerging BFRs could not be determined due to the high number of samples below the limit of detection. The highest muscle ΣPFAS levels were quantified in fetuses (23 ± 8.7 ng/g ww), followed by adult males (7.2 ± 2.0 ng/gg ww) and adult females (4.5 ± 1.1 ng/g ww), showing substantial placental transfer from mother to fetus. In contrast, Hg levels in the fetus were lower than the mother. Levels were under thresholds for risk of health effects in the whales. This study is the first to report occurrence and placental transfer of emerging contaminants in common minke whales from the Barents Sea, contributing valuable new data on pollutant levels in Arctic wildlife.publishedVersio
Monitoring program for pharmaceuticals, illegal substances, and contaminants in farmed fish - Annual report for 2022
Get PDFThis report summarises the monitoring data collected in 2022 on the status of illegal substances, pharmaceuticals and contaminants in Norwegian farmed fish. In 2022, a total of 15040 fish were sampled. Samples examined for illegal compounds were collected at all stages of farming and are representative of farmed fish under production. The samples were analysed for substances with anabolic effects or unauthorized substances. No residues of illegal compounds were detected. Samples tested for approved veterinary drugs and contaminants were collected at processing plants and are representative of Norwegian farmed fish ready for human consumption. Residues of the anti-sealice agents emamectin, lufenuron and imidacloprid were found. In addition, residues of cypermethrin and deltamethrin were detected; both substances used as chemical delousing, but also as plant protection agents. Residue concentrations for all samples were below the respective Maximum Residue Limits (MRLs). Other veterinary drugs, like antibiotics or drugs used against internal parasites were not found. No environmental contaminants were found above the EU maximum level.publishedVersio
Dietary zinc, selenium and water temperature during early seawater phase influences the development of vertebral deformities and cataract in adult Atlantic salmon
Get PDFThe impact of dietary trace minerals (TM; zinc and selenium) and water temperature during early seawater phase on the development of vertebral deformities and cataracts in adult Atlantic salmon was studied. Two experimental feeds (control and High TM) and two water temperatures (12 and 16 °C) were designed in a 2 × 2 factorial arrangement. The Zn and Se levels in the control and high TM diet corresponded to 150 or 200 mg Zn/kg and 0.5 or 0.7 mg Se/kg diet, respectively. Atlantic salmon post-smolts (mean weight, 138 g) were distributed in 12 tanks and were randomly assigned to one of the treatments in triplicate groups. The experimental regime lasted for 12 weeks and thereafter the fish were sampled or transferred to three net pens comprising all four treatments in a common garden. The fish were further grown on a common commercial feed and assessed for vertebral deformities and cataracts as adults (4 to 4.5 kg). Atlantic salmon post-smolt fed the control diet or reared at 16 °C grew more than those fed the high TM diet or reared at 12 °C at the end of the 12-week experimental feeding period. Vertebral mineral density, concentration of Zn and Se in the whole body, plasma and bile were influenced by the dietary treatments. The fast growth rates observed in the control diet and 16 °C exposed fish were associated with increased risk of vertebral deformities and cataract at adult stage. The preventive effect of the high TM diet on incidence and severity of vertebral deformities and cataracts was highly effective if the fish were reared at 12 °C during early seawater phase, but was reduced or absent if reared at 16 °C. Cataract inducing effect of high temperature at 16 °C was much stronger than the cataract mitigating effect of high TM diet at 16 °C. Overall, feeding Atlantic salmon post-smolts a high TM diet (Zn: 200 mg/kg; Se: 0.7 mg/kg diet) during early seawater phase for 12 weeks reduced the incidence of vertebral deformity and cataracts in adult fish, albeit subject to water temperature.publishedVersio
A Review of Pink Salmon in the Pacific, Arctic, and Atlantic Oceans
Get PDFThe Northern Hemisphere Pink Salmon Expert Group Meeting was held on October 2–3, 2022 in Vancouver, Canada, immediately preceding the International Year of the Salmon (IYS) Synthesis Symposium. The rapid expansion of pink salmon was the theme for the meeting, and experts came together to discuss the current state of knowledge for pink salmon. Specific topics of focus included the range expansion into the Atlantic and Arctic oceans, trends in distribution and abundance, research and monitoring approaches, potential inter-specific interactions, mitigation efforts, and plans for future collaborations. The outcomes of the meeting were presented at the IYS Synthesis Symposium and are further disseminated through this NPAFC Technical Report. The Executive Summary section of this report provides a brief background, a condensed overview of each topic, and concludes with overarching takeaway messages that are intended to guide future collaborations.publishedVersio
Advice on fishing opportunities for Northeast Arctic cod in 2024 in ICES subareas 1 and 2
Get PDFStock Name: Northeast Arctic cod (ICES areas 1 and 2)
The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the Joint Norwegian–Russian Fisheries Commission management plan is applied, catches in 2024 should be no more than 453 427 tonnes.publishedVersio
Quality of fish sludge as fertiliser to spring cereals: Nitrogen effects and environmental pollutants
Get PDFThe aim of this study was to contribute to development of organic fertiliser products based on fish sludge (i.e. feed residues and faeces) from farmed smolt. Four dried fish sludge products, one liquid digestate after anaerobic digestion and one dried digestate were collected at Norwegian smolt hatcheries in 2019 and 2020. Their quality as fertilisers was studied by chemical analyses, two 2-year field experiments with spring cereals and soil incubation combined with a first-order kinetics N release model. Cadmium (Cd) and zinc (Zn) concentrations were below European Union maximum limits for organic fertilisers in all products except one (liquid digestate). Relevant organic pollutants (PCB7, PBDE7, PCDD/F + DL-PCB) were analysed for the first time and detected in all fish sludge products. Nutrient composition was unbalanced, with low nitrogen/phosphorus (N/P) ratio and low potassium (K) content relative to crop requirements. Nitrogen concentration in the dried fish sludge products varied (27–70 g N kg-1 dry matter), even when treated by the same technology but sampled at different locations and/or times. In the dried fish sludge products, N was mainly present as recalcitrant organic N, resulting in lower grain yield than with mineral N fertiliser. Digestate showed equally good N fertilisation effect as mineral N fertiliser, but drying reduced N quality. Soil incubation in combination with modelling is a relatively cheap tool that can give a good indication of N quality in fish sludge products with unknown fertilisation effects. Carbon/N ratio in dried fish sludge can also be used as an indicator of N quality.publishedVersio
The role of chloroplast movement in C<inf>4</inf>photosynthesis: A theoretical analysis using a three-dimensional reaction-diffusion model for maize
Get PDFChloroplasts movement within mesophyll cells in C4 plants is hypothesized to enhance the CO2 concentrating mechanism, but this is difficult to verify experimentally. A three-dimensional (3D) leaf model can help analyse how chloroplast movement influences the operation of the CO2 concentrating mechanism. The first volumetric reaction–diffusion model of C4 photosynthesis that incorporates detailed 3D leaf anatomy, light propagation, ATP and NADPH production, and CO2, O2 and bicarbonate concentration driven by diffusional and assimilation/emission processes was developed. It was implemented for maize leaves to simulate various chloroplast movement scenarios within mesophyll cells: the movement of all mesophyll chloroplasts towards bundle sheath cells (aggregative movement) and movement of only those of interveinal mesophyll cells towards bundle sheath cells (avoidance movement). Light absorbed by bundle sheath chloroplasts relative to mesophyll chloroplasts increased in both cases. Avoidance movement decreased light absorption by mesophyll chloroplasts considerably. Consequently, total ATP and NADPH production and net photosynthetic rate increased for aggregative movement and decreased for avoidance movement compared with the default case of no chloroplast movement at high light intensities. Leakiness increased in both chloroplast movement scenarios due to the imbalance in energy production and demand in mesophyll and bundle sheath cells. These results suggest the need to design strategies for coordinated increases in electron transport and Rubisco activities for an efficient CO2 concentrating mechanism at very high light intensities.publishedVersio
Antarctic krill (Euphausia superba) catch weight estimated with a trawl-mounted echosounder during fishing
Get PDFReporting reliable catch weight estimates is important for all fisheries management. This study explores the potential for precise and direct estimation of catch weight (green weight) for the Antarctic krill (Euphausia superba) fishery by employing a high frequency acoustic sensor in the trawl. Trials were performed off the coast of the South Orkney Islands during February 2020 using a scientific macroplankton trawl and echosounder providing a 18° beam pointing downwards across the fishing circle at the trawl mouth. The acoustically estimated catch weight and the observed catch weight had a linear relationship (R2 = 0.87, F(1,10) = 69.6, p < 0.000) where the acoustically estimated catch weight significantly predicted actual catch weight (β = 1.20, p = 0.000). The acoustic vertical densities of krill increased toward the center of the trawl opening suggesting that krill were herded during fishing. The current study demonstrates that acoustically based catch weight monitoring has the potential to be used for reporting total krill catch weight in each trawl, potentially in real-time, and that similar methods could also be employed in similar types of trawl fisheries.publishedVersio
Sea pens and bamboo corals in Skagerrak and the Norwegian trench
Get PDFThis study presents the distribution and abundance of key species of the vulnerable marine ecosystems (VMEs) ‘Coral gardens’ and ‘Sea pen and burrowing megafauna’ in Skagerrak and the Norwegian trench. It is based on 543 bycatches from 2017–2021, and 35 ROV dives from 2016-2017. Bycatches were used to indicate distribution and relative abundance of the VME key species while ROV observations provided information on colony densities, associated fauna and damages. Four sea pen species were recorded. Funiculina quadrangularis and Kophobelemnon stelliferum were widely distributed and most abundant below 200 meters. The few records of Pennatula phosphorea were mainly from shallower than 100 meters, and the rare Balticina finmarchica primarily occurred below 200 meters. The ROV videos confirmed the pattern from the bycatches, however, colony densities were much higher, and the sea pen Virgularia mirabilis recorded in high abundances was not present in bycatches. The coral garden key species Isidella lofotensis, endemic to Norway, had a restricted area of occurrence confirmed by both methodologies. The restricted distribution makes it particularly vulnerable. Fishing activities overlap with the VMEs distribution and the observations of sea pen skeletons and the coral predatory anemone Ptychodactis patula are indicative of pressure from bottom trawl fishing.publishedVersio
Seasonal patterns of vertical flux in the northwestern Barents Sea under Atlantic Water influence and sea-ice decline
Get PDFThe northern Barents Sea is a productive Arctic inflow shelf with a seasonal ice cover and as such, a location with an efficient downward export of particulate organic matter through the biological carbon pump. The region is under strong influence of Atlantification and sea-ice decline, resulting in a longer open water and summer period. In order to understand how these processes influence the biological carbon pump, it is important to identify the seasonal and spatial dynamics of downward vertical flux of particulate organic matter. In 2019 and 2021, short-term sediment traps were deployed between 30 and 200 m depth along a latitudinal transect in the northwestern Barents Sea during March, May, August and December. Vertical flux of particulate organic carbon, δ13C and δ15N values, Chl-a, protists and fecal pellets were assessed. We identified a clear seasonal pattern, with highest vertical flux in May and August (178 ± 202 and 159 ± 79 mg C m−2 d−1, respectively). Fluxes in December and March were < 45 mg C m−2 d−1. May was characterized by diatom- and Chl a-rich fluxes and high spatial variability, while fluxes in August had a higher contribution of fecal pellets and small flagellates, and were spatially more homogenous. Standing stocks of suspended particulate organic matter were highest in August, suggesting a more efficient retention system in late summer. The strong latitudinal sea-ice gradient and the influence of Atlantic Water probably led to the high spatial variability of vertical flux in spring, due to their influence on primary productivity. We conclude that the efficiency of the biological carbon pump in a prolonged open-water period depends on the reworking of small, slow sinking material into efficiently sinking fecal pellets or aggregates, and the occurrence of mixing.publishedVersio