326 research outputs found

    Report on the beach seine survey in Oslofjord 2014

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    This report gives a short summary of the basic findings on some key species sampled in the beach seine survey in the inner Oslofjord in 2014. The beach seine survey has been conducted in its present form since 1919. Cod recruitment in the area in 2014 was low even compared to the historical low trend the most recent years. No recruits of cod were found in the Inner Oslofjord and neither was there any adult cod. A general impression is that warmer water species have had an increase the last 20 years. There also seems to be an increase in pelagic species at the cost of some benthic specie

    Gels and gelled emulsions prepared by acid-induced gelation of mixtures of faba bean (Vicia faba) protein concentrate and λ-carrageenan

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    In this study, gels were successfully prepared at room temperature from mixtures of dry fractionated faba bean protein concentrate (FPC) and λ-carrageenan (λ-CGN), through acidification with glucono-ÎŽ-lactone (GDL). At neutral pH, the mixtures were shear thinning liquids, although the shear viscosity increased dramatically with λ-CGN addition. After adding GDL, the gelling kinetics were followed through small amplitude oscillatory rheology for 19 hours, at which point all gels had reached a gel modulus plateau. Elastic moduli for the prepared gels were in the range of 1500 – 4500 Pa, dependent on FPC:λ-CGN ratio and concentrations, and final pH (3.5 – 4). Rheological data further indicated the gels had properties typical of aggregated particle gels, e.g., low yield strains (∌1%). All gels showed some syneresis upon centrifugation (2000g), with the least amount of syneresis (15 – 20%) at the highest λ-CGN concentrations (1.5 – 2%). FPC is a good emulsifier, and gelled emulsions were successfully prepared. Inclusion of emulsion droplets had significant impact on the gel network, with ∌40% and ∌60% increased gel storage modulus at 20% and 30% oil, respectively. Preparing similar formulations using a more extensively processed commercial faba bean protein isolate was also attempted, but this resulted in poor gels with very high syneresis. This indicates that dry fractionation methods may be beneficial to preserve native protein functionality.Gels and gelled emulsions prepared by acid-induced gelation of mixtures of faba bean (Vicia faba) protein concentrate and λ-carrageenanpublishedVersio

    Rapport fra hĂžstundersĂžkelsene med strandnot i indre og ytre Oslofjord 2018

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    Rapporten oppsummerer resultater fra funn som ble gjort ved gjennomfÞring av forsÞksfiske med strandnot i indre og ytre Oslofjord i 2018. Registreringene er gjort som del av Havforskningsinstituttets hÞstundersÞkelse som har pÄgÄtt siden 1919 (med de tilleggsstasjoner som er dekket for formÄl av denne rapporten). Rekruttering av torsk i Indre Oslofjord var i 2018 svÊrt lav, ogsÄ sett i forhold til de siste Ärene hvor trenden har vÊrt pÄ et historisk lavt nivÄ. Det ble fanget kun 3 yngel av torsk pÄ 56 trekk fra Sandefjord og Þstover. Det ble pÄ de samme stasjonene ogsÄ bare fanget 1 eldre torsk ved Ärets nottrekk. De varmekjÊre artene har hatt et oppsving de siste 20 Ärene, og spesielt ser vi at pelagiske arter overtar for bentiske.publishedVersio

    Development of ten microsatellite loci in the marine fish ling (Molva molva)

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    Journal homepage: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1755-0998/issuesWe developed primers for two dinucleotide and eight tetranucleotide microsatellite loci in a marine fish, the ling (Molva molva). All markers were obtained from partial genomic DNA libraries and characterized in 55 unrelated individuals from one putative population. The number of alleles ranged from five to 24 (average 10.5) per locus, and the observed heterozygosity ranged from 0.218 to 0.981 (average 0.643). No loci amplified in two other gadoid species tested, the Atlantic cod (Gadus morhua) and the tusk (Brosme brosme)

    Demographic responses to protection from harvesting in a long-lived marine species

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    Marine protected areas (MPAs) are usually considered to have positive effects on the recovery of over-exploited populations. However, resolving the extent to which MPAs function according to their conservation goals re- quires that essential demographic information such as individual survival and population size are quantified. To this end, we analyzed a 16-year replicated mark-recapture study on European lobster (Homarus gammarus, n = 8793) conducted at several protected and unprotected sites in southern Norway, quantifying the impact of MPAs on local population dynamics by means of a “before-after control-impact” study approach (BACI). Lobster sur- vival and abundance were estimated by applying multi-state and robust design models to the mark-recapture data. These models revealed underlying positive responses to protection. Annual survival rates and population abundances reached higher values in the MPAs, compared to the unprotected sites (abundance range: MPAs = 96–1172, control areas = 92–747). In general, female survival was higher than male survival (range of survival: male = 0.13–0.75, female = 0.37–0.85), while larger males benefited more from protection compared to smaller males (range of increase in survival after protection: big = 100–125%, small = 55–101%). We also detected regional differences in demographic responses to protection, as not all MPAs showed the same changes in abundance over time. Our results show that MPAs can reach conservation goals by increasing the local survival and abundance of lobster, but they also highlight demographic differences between sexes and geographic areas that are worth considering for the management and design of both current and future MPAs.publishedVersio

    Lobster and cod benefit from small-scale northern marine protected areas: inference from an empirical before - after control-impact study

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    Marine protected areas (MPAs) are increasingly implemented as tools to conserve and manage fisheries and target species. Because there are opportunity costs to conservation, there is a need for science-based assessment of MPAs. Here, we present one of the northernmost documentations of MPA effects to date, demonstrated by a replicated before-after control-impact (BACI) approach. In 2006, MPAs were implemented along the Norwegian Skagerrak coast offering complete protection to shellfish and partial protection to fish. By 2010, European lobster (Homarus gammarus) catch-per-unit-effort (CPUE) had increased by 245 per cent in MPAs, whereas CPUE in control areas had increased by 87 per cent. Mean size of lobsters increased by 13 per cent in MPAs, whereas increase in control areas was negligible. Furthermore, MPA-responses and population development in control areas varied significantly among regions. This illustrates the importance of a replicated BACI design for reaching robust conclusions and management decisions. Partial protection of Atlantic cod (Gadus morhua) was followed by an increase in population density and body size compared with control areas. By 2010, MPA cod were on average 5 cm longer than in any of the control areas. MPAs can be useful management tools in rebuilding and conserving portions of depleted lobster populations in northern temperate waters, and even for a mobile temperate fish species such as the Atlantic cod

    Can we rely on selected genetic markers for population identification? Evidence from coastal Atlantic cod

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    The use of genetic markers under putative selection in population studies carries the potential for erroneous identification of populations and misassignment of individuals to population of origin. Selected markers are nevertheless attractive, especially in marine organisms that are characterized by weak population structure at neutral loci. Highly fecund species may tolerate the cost of strong selective mortality during early life stages, potentially leading to a shift in offspring genotypes away from the parental proportions. In Atlantic cod, recent genetic studies have uncovered different genotype clusters apparently representing phenotypically cryptic populations that coexist in coastal waters. Here, we tested if a high‐graded SNP panel specifically designed to classify individual cod to population of origin may be unreliable because of natural selection acting on the SNPs or their linked background. Temporal samples of cod were collected from two fjords, starting at the earliest life stage (pelagic eggs) and carried on until late autumn (bottom‐settled juveniles), covering the period during summer of high natural mortality. Despite the potential for selective mortality during the study period, we found no evidence for selection, as both cod types occurred throughout the season, already in the earliest egg samples, and there was no evidence for a shift during the season in the proportions of one or the other type. We conclude that high‐graded marker panels under putative natural selection represent a valid and useful tool for identifying biological population structure in this highly fecund species and presumably in others.publishedVersio

    Egg distribution, bottom topography and small-scale cod population structure in a coastal marine system

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    Coastal marine species with pelagic egg and larval stages, such as the Atlantic cod Gadus morhua, can be structured into genetically distinct local populations on a surprisingly small geographic scale considering their dispersal potential. Mechanisms responsible for such small-scale genetic structure may involve homing of adults to their natal spawning grounds, but also local retention of pelagic eggs and larvae. For example, spawning within sheltered fjord habitats is expected to favour local retention of early life stages. Here, we studied the distribution of cod eggs along inshore-offshore transects in 20 Norwegian fjords. The general pattern exhibited across all fjords was a higher concentration of cod eggs inside the fjords than further offshore. In particular, fjords with shallow sills (model threshold 37 m) show an abrupt reduction in egg density over the sill. This study provides empirical support for an offspring retention hypothesis, which may help to explain the maintenance of local population structure in pelagic marine systems

    Effect of temperature during flowering, pod set, and seed development on yield components and accumulation of protein, starch, and low molecular weight carbohydrates in two faba bean (Vicia faba L.) cultivars

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    The aim was to explore the impact of temperature during seed development on yield performance and seed quality in faba bean when grown at cool temperatures representative for high latitude regions. Two varieties, an early and a medium late maturing, were grown in climate chambers with three temperature regimes (day/night temperatures of 14°C/12°C, 19°C/12°C, and 24°C/12°C) from onset of flowering to maturation. Yield components were recorded, and the accumulation of protein, starch, and low molecular weight carbohydrates including the raffinose family oligosaccharides was followed during the accumulation phase until physiological maturity. The lower temperature regimes strongly delayed pod and seed development compared with 24°C/12°C. Temperature affected the number of pods per plant for the upper node group. Plants grown at 19°C had the highest total dry seed weight compared with plants grown at 14°C and 24°C. Temperature per se did not influence the content of starch, protein, and low molecular weight carbohydrates, while their accumulation followed the moisture content in the seed, and thus the seed development stage. The content of raffinose family oligosaccharides increased sharply when the seed moisture dropped below 70% and leveled off at about 40% and 50% moisture for verbascose and stachyose, respectively, coinciding with physiological maturity. The results provide more knowledge about the seed maturation and accumulation in faba bean under low temperatures, important for cultivation under high latitude regions.Effect of temperature during flowering, pod set, and seed development on yield components and accumulation of protein, starch, and low molecular weight carbohydrates in two faba bean (Vicia faba L.) cultivarspublishedVersio
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