Atlantic mackerel (Scomber scombrus L.) is a widely distributed commercially important pelagic species. Little is known about the stock structure of this species, but it is thought to be undergoing a range extension due to environmental changes. Knowledge of the stock structure under these changing conditions is fundamental for effective management. In this paper, 30 highly polymorphic microsatellite loci developed with next generation sequencing are described. The number of alleles per locus ranged from 4 to 39 in two geographically distant populations, observed and expected heterozygosities ranged between 0.370–0.978 and 0.426–0.962, respectively. These loci are an important resource that will allow assessment of the current population genetic structure of this species, and enable monitoring of climate related changes in the species range and distribution.
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Data on distribution, concentration and trends of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) is scarce in biota from the sub-Arctic region of the Atlantic. The present study is an investigation on PBDE and HBCD concentrations in eggs from seven marine bird species from Iceland, ie common eider (Somateria mollissima), arctic tern (Sterna paradisaea), guillemot (Uria algae), fulmar (Fulmarus glacialis), lesser black-backed gull (Larus fuscus), great black-backed gull (Larus marinus) and great skua (Stercorarius skua). Concentrations of sum PBDEs ranged from 44 ng g−1 fat in eider eggs to 2400 ng g−1 fat in great skua eggs. The contribution of different PBDE congeners to the sum concentration differed between species. Concentration of HBCDs (sum of α−, β- and γ − HBCD) ranged from 1.3 ng g−1 fat in arctic tern eggs to 41 ng g−1 fat in great black-backed gull. PCA on PBDE and HBCD shows different trends between the two BFR groups, further indicating different sources / usage. Investigations on any potential health or population effects of environmental pollutants on the great skua are advised since both the PBDE and HBCD concentrations are high.
The genomic architecture underlying ecological divergence and ecological speciation with gene flow is still largely unknown for most organisms. One central question is whether divergence is genome-wide or localized in 'genomic mosaics' during early stages when gene flow is still pronounced. Empirical work has so far been limited, and the relative impacts of gene flow and natural selection on genomic patterns have not been fully explored. Here, we use ecotypes of Atlantic cod to investigate genomic patterns of diversity and population differentiation in a natural system characterized by high gene flow and large effective population sizes, properties which theoretically could restrict divergence in local genomic regions. We identify a genomic region of strong population differentiation, extending over approximately 20 cM, between pairs of migratory and stationary ecotypes examined at two different localities. Furthermore, the region is characterized by markedly reduced levels of genetic diversity in migratory ecotype samples. The results highlight the genomic region, or 'genomic island', as potentially associated with ecological divergence and suggest the involvement of a selective sweep. Finally, we also confirm earlier findings of localized genomic differentiation in three other linkage groups associated with divergence among eastern Atlantic populations. Thus, although the underlying mechanisms are still unknown, the results suggest that 'genomic mosaics' of differentiation may even be found under high levels of gene flow and that marine fishes may provide insightful model systems for studying and identifying initial targets of selection during ecological divergence .
The EU project BRAFO proposed a framework for risk – benefit assessment of foods, or changes in diet, that present both potential risks and potential benefits to consumers (Hoekstra et al., 2012a). In higher tiers of the BRAFO framework, risks and benefits are integrated quantitatively to estimate net health impact measured in DALYs or QALYs (disability- or quality-adjusted life years). This paper describes a general model that was developed by a second EU project, Qalibra, to assist users in conducting these assessments. Its flexible design makes it applicable to a wide range of dietary questions involving different nutrients, contaminants and health effects. Account can be taken of variation between consumers in their diets and also other characteristics relevant to the estimation of risk and benefit, such as body weight, gender and age. Uncertainty in any input parameter may be quantified probabilistically, using probability distributions, or deterministically by repeating the assessment with alternative assumptions. Uncertainties that are not quantified should be evaluated qualitatively. Outputs produced by the model are illustrated using results from a simple assessment of fish consumption. More detailed case studies on oily fish and phytosterols are presented in companion papers. The model can be accessed as web-based software at www.qalibra.eu.
Heating and changes in pH often practiced during fish protein hydrolysis can cause lipid oxidation. The effect of natural antioxidants towards haemoglobin-mediated lipid oxidation during enzymatic hydrolysis of cod proteins was investigated. Different variants of a washed cod model system, containing different combinations of haemoglobin and natural antioxidants (l-ascorbic acid and Fuscus vesiculosus extract), were hydrolyzed using Protease P “Amano” 6 at pH 8 and 36 ° C to achieve 20% degree of hydrolysis. Lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS) were analyzed periodically during the hydrolysis process. The in vitro antioxidant activity of the final products was investigated. Results indicate that oxidation can develop rapidly during hydrolysis and antioxidant strategies are preferable to produce good quality products. Oxidation products did not have an impact on the in vitro antioxidant activity of the hydrolysates. The natural antioxidants inhibited oxidation during hydrolysis and contributed to the antioxidant activity of the final product.
Although the tendency of Atlantic salmon Salmo salar to form differentiated populations among rivers and among tributaries within large river systems (> 100 km-long) is well documented, much less is known about population structure within small river systems (<30 km-long). In the present study, we investigated the genetic effects of straying of hatchery-reared salmon on population structure and genetic composition within the Ellidaár river system, a small system (21 km total length) in SW Iceland. We analyzed spatial and temporal variation of wild and domesticated samples (farmed and ranched; n = 931) using seven microsatellite loci. Estimates of population differentiation [FST, genetic tree (DA)] and Bayesian cluster analysis (STRUCTURE) revealed a significant population structure as well as relative long-term temporal stability of the genetic composition in the main river from 1948 to 2005. However, the genetic composition of the tributary populations was unstable and genetically homogenized in recent years. Wild-hatchery hybrids were detected during the influx of strays as well as a few years after, suggesting that introgression has changed the genetic composition of the wild populations. More investigations are needed in Iceland and elsewhere on possible fine-scale population differentiation and factors leading to it. Fine-scale population differentiation as observed in the present study has implications for the resolution with which harvest and habitat management of salmon should be conducted. In addition, farming and ranching operations should be located to minimize potential negative effects of strays on wild fish.
The food production industry has in recent years had to answer calls for environmentally friendly strategies and methods of communicating these effectively.This need is seen clearly in the fisheries sector where the concerns regarding the environment, ethical production and economic sustainability are driving forces for greater knowledge about the sustainability impact of a product or company. How these concerns and needs translate into requirements from the industry is poorly described in the literature. This study investigated these requirements within the framework of a theoretical tool which the stakeholders could use in the future. The results of the research carried out here show that stakeholders, through the fisheries supply chain, wish to use sustainability data for marketing purposes, internal benchmarking and improvement of environmental impact. The main challenge reported is to design a measurement tool that can be used in different conditions whilst still maintaining that integrity.
A soft thermo-reversible protein gel was studied with respect to failure. Flow curves recorded at constant shear rates revealed a dynamic yield stress σy, seen as a stress plateau below about 10 s−1. When a shear stress below σy was applied to fractured gels, they reformed after a time that increased with increasing stress and diverged at σy. Application of shear stress to fresh gels led to an initial elastic response followed by creep. Following this creep regime, the strain stagnated below the dynamic yield stress σy, while for σ > σy failure was observed after a time that increased with decreasing stress and diverged at σ = σy. The time-to-failure dependence on the stress for σ > σy, with two distinct exponential scaling regimes, agrees with existing proposed theories for the fracture of colloidal strands.
The identification of molecular structures of an arsenolipid is pivotal for its toxicological assessment and in understanding the arsenic cycling in the environment. However, the analysis of these compounds in a lipid matrix is an ongoing challenge. So far, only a few arsenolipids have been reported, including arsenic fatty acids (AsFAs) and arsenic hydrocarbons (AsHCs). By means of RP-HPLC-ICPMS / ESMS, we investigated Capelin oil (Mallotus villosus) for possible new species of arsenolipids. Twelve arsenolipids were identified in the fish oil including three AsFAs and seven AsHCs. Among the AsHCs, four that were identified had protonotated molecular masses of 305, 331, 347, and 359 and have not been reported before. In addition, the compounds with molecular formulas C20H44AsO+ and C24H44AsO+ were found in low concentrations and showed chromatographic properties and MS data consistent with cationic trimethylarsenio fatty alcohols. Derivatization by acetylation and thiolation coupled with accurate mass spectrometry was successfully used to establish the occurrence of this new class of arsenolipids as cationic trimethylarsenio fatty alcohols (TMAsFOH).
Sea cucumbers are used as healthy food, traditional medicine and dietary supplement. Sulphated polysaccharides (sPS) from their body wall possess variety of biological activities; however the immunomodulatory effects of sea cucumber polysaccharides remain unknown. Three sPS fractions were isolated from orange-footed sea cucumber (Cucumaria frondosa) and their effects on DC maturation investigated. DCs, matured in the presence of high molecular weight FCF-1 (100 and 1000 /g / ml) with a monosaccharide composition of NANA, GlcNAc, Man, Gal, Fuc and GalNAc (40: 13: 12: 12: 9: 8: 3), secreted reduced levels of IL-10, IL-12p40 and IL-6 (only at 1000 /g / ml). Furthermore, allogeneic CD4+ T cells co-cultured with DCs matured with FCF-1 (100 /g / ml) secreted reduced levels of IFN-γ and increased levels of IL-17 than allogeneic CD4+ T cells co-cultured with DCs matured without FCF-1. These data suggest that FCF-1 can affect DC maturation leading to increased Th17 and reduced Th1 activity; thus, increasing the Th17-mediated defense against yeast and extracellular bacteria.