1,649 research outputs found

    The effects of subsampling and between-haul variation on the size-selectivity estimation of Chilean hake (Merluccius gayi gayi)

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    Using the data collected in a size selectivity experiment on Chilean hake (Merluccius gayi gayi) carried out in 2000, the selectivity parameters for four codend mesh sizes (100, 110, 130, and 140 mm of mesh size opening) were estimated and modelled by the SELECT model. These analyses included considerations of the sampling proportions of the catch in the codend and cover. Furthermore, the analyses took into account between-haul variation. The l(50) values were 30.8, 29.9, 30.0, and 41.2 cm of total length, respectively, values lower than the estimates obtained from previous studies. The contribution of explanatory variables to the selectivity model was also tested in order to determine the role of mesh size, catch size (in number), and towing speed. Increases in catch size and in towing speed were accompanied by decreases in the l(50) estimates. These results demonstrate how incorporation of subsampling effect and explanatory variables to model between-haul variation can improve selectivity estimates and management of a valuable resource

    Transcriptome and Biochemical Analysis of a Flower Color Polymorphism in Silene littorea (Caryophyllaceae)

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    Flower color polymorphisms are widely used as model traits from genetics to ecology, yet determining the biochemical and molecular basis can be challenging. Anthocyanin-based flower color variations can be caused by at least 12 structural and three regulatory genes in the anthocyanin biosynthetic pathway (ABP). We use mRNA-Seq to simultaneously sequence and estimate expression of these candidate genes in nine samples of Silene littorea representing three color morphs (dark pink, light pink, and white) across three developmental stages in hopes of identifying the cause of flower color variation. We identified 29 putative paralogs for the 15 candidate genes in the ABP. We assembled complete coding sequences for 16 structural loci and nine of ten regulatory loci. Among these 29 putative paralogs, we identified 622 SNPs, yet only nine synonymous SNPs in Ans had allele frequencies that differentiated pigmented petals (dark pink and light pink) from white petals. These Ans allele frequency differences were further investigated with an expanded sequencing survey of 38 individuals, yet no SNPs consistently differentiated the color morphs. We also found one locus, F3h1, with strong differential expression between pigmented and white samples (\u3e42x). This may be caused by decreased expression of Myb1a in white petal buds. Myb1a in S. littorea is a regulatory locus closely related to Subgroup 7 Mybs known to regulate F3h and other loci in the first half of the ABP in model species. We then compare the mRNA-Seq results with petal biochemistry which revealed cyanidin as the primary anthocyanin and five flavonoid intermediates. Concentrations of three of the flavonoid intermediates were significantly lower in white petals than in pigmented petals (rutin, quercetin and isovitexin). The biochemistry results for rutin, quercetin, luteolin and apigenin are consistent with the transcriptome results suggesting a blockage at F3h, possibly caused by downregulation of Myb1a

    A software tool for monitoring legal minimum lenght of landings: Case study of a fishery in sourthern Spain

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    Herramienta de interés para el control y la gestión de pesqueríasThe regulation of minimum legal size(MLS) of catches is a tool widely applied in the management of fisheries resources, although the MLS does not always coincide with the length at first maturit(LFM). The optimization of this management tool requires a series of quality control in fish markets and transportation. A software application has been developed to make the control of the landings of several target species easier and faster. In order to test and make this tool operational,six species of commercial interest were selected: four species of fish hand two species of bivalves. It is proposed to estimate the proportion of illegal specimens in the studied lot from the proportion of illegal individuals found in the samples taken from this lot.The input data for the application are the minimum legal size(MLS) of the species and the total length(TL)of each specimen sampled. The out put data is a statistical summary of the percentage of specimens of size less than the legal minimum(TL<=MLS)within different confidence intervals(90%,95% and 99%). The software developed will serve as a fast,efficient and easy to manage tool that allows inspectors to determine the degree of compliance on MLS control and to make a decision supported by statistical proof on fishing goods

    Understanding Prenatal Iodine Deficiency

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    Aproximación al conocimiento de la flora alóctona de la provincia de Málaga (España): catálogo de metáfitos

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    First list of alien flora for Malaga province (Spain)Palabras clave. Flora alóctona, invasora, metáfitos, Málaga, España.Key words. Alien flora, invasive species, metaphytes, Malaga, Spain

    Cross-species tests of 45 microsatellite loci isolated from different species of ungulates in the Iberian red deer (Cervus elaphus hispanicus) to generate a multiplex panel

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    The Iberian red deer (Cervus elaphus hispanicus) is an emblematic game species in Spain. To generate a battery of polymorphic markers for multiplex polymerase chain reactions for the Spanish red deer, 45 loci isolated in different species of ungulates were tested. Of the primers tested, 27 amplified but only 21 were polymorphic. Eleven of these markers were subsequently optimized for multiplex in four polymerase chain reactions. This allows analysing several molecular markers jointly to substantially reduce costs. Finally, we report descriptive summary statistics such as number of alleles for the former and also test of disequilibria and heterozygosity for the latter. © 2008 The Authors.Peer Reviewe

    A simple method to estimate the significance level of the catch probability in the catch removal method in riverf ish populations

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    This work presents a method for estimating the signi®cance level of the capture probability when the capture removal method is used in riverine ®sh populations. The method is based on adjustment of the linear relationship between capture probability and an index of capture ef®cacy. With this method the population size, the statistic 2 and the signi®cance level of the capture probability can be estimated. This is a simple technique which can be applied in the ®eld at the time of sampling. It does not require the use of computers and can determine in situ whether the catch is valid to calculate the population density

    Novedades para el Pre-Rif del Jbel Zalagh (Marruecos)

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    New taxa from the Pre-Rif of the Jbel Zalagh (Morocco)Palabras clave. Flora, corología, Pre-Rif, Jbel Zalagh, N Marruecos.Key words. Flora, chorology, Pre-Rif, Jbel Zalagh, Norther Morocco

    Some meristic characteristics of hybrids between Acipenser naccarii and Acipenser baerii

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    The aim of this study was to describe meristic characters of hybrid Acipenser naccarii x A. baeri, to be used as the basis for characterizing hybrid specimens in a complementary manner to as described for A. naccarii by Hernando et al. (1999). Thirty 2+ and 3+ year class individuals from the Region of Lombardy (Italy) were analysed for eight morphological variables (Soljan 1975; Holcick et al. 1989), and weight. Three indices, viz the relative position of barbels (CA), the ratio of snout width to length (FB) (Garrido-Ramos et al. 1997), and the Soljan index (Hernando et al. 1999), were used to characterize hybrids. A descriptive analyses of variables, simple and multiple regression analysis, and principal components relationships, were calculated. The relationships between TI and the indices was described using a stepwise multiple regression analysis: TI = 33.32 - 0.26 CA + 10.49 FB + 74.45 SOLJ (F = 1.96; Df = 3 )

    Fur or feather? Feeding preferences of species of Culicoides biting midges in Europe

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    © 2014 Elsevier Ltd. Understanding the feeding preferences of haematophagous insects is critical to depicting the amplification and transmission networks of pathogens and identifying key vector species for surveillance programs. In the case of species from genus Culicoides, many of which are important vectors of pathogens causing animal diseases, information from molecular studies on the feeding habits of females is expanding but still limited for a significant fraction of competent vectors of Culicoides-borne pathogens. In spite of these limitations, recent studies highlight that most Culicoides species are able to feed on several vertebrate species, but present clear preferences for mammals or birds.Peer Reviewe
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