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  • 1
    Online Resource
    Online Resource
    Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community
    Oxford University Press (OUP) ; 2012
    In:  ICES Journal of Marine Science Vol. 69, No. 1 ( 2012-01-01), p. 8-22
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 69, No. 1 ( 2012-01-01), p. 8-22
    Abstract: Greenstreet, S. P. R., Fraser, H. M., Rogers, S. I., Trenkel, V. M., Simpson, S. D., and Pinnegar, J. K. 2012. Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community. – ICES Journal of Marine Science, 69: 8–22. Broader ecosystem management objectives for North Sea demersal fish currently focus on restoring community size structure. However, most policy drivers explicitly concentrate on restoring and conserving biodiversity, and it has not yet been established that simply restoring demersal fish size composition will be sufficient to reverse declines in biodiversity and ensure a generally healthy community. If different aspects of community composition, structure, and function vary independently, then to monitor all aspects of community general health will require application of a suite of metrics. This assumes low redundancy among the metrics used in any such suite and implies that addressing biodiversity issues specifically will require explicit management objectives for particular biodiversity metrics. This issue of metric redundancy is addressed, and 15 metrics covering five main attributes of community composition, structure, and function are applied to groundfish survey data. Factor analysis suggested a new interpretation of the metric information and indicated that a minimum suite of seven metrics was necessary to ensure that all changes in the general health of the North Sea demersal fish community were monitored properly. Covariance among size-based and species-diversity metrics was low, implying that restoration of community size structure would not necessarily reverse declines in species diversity.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1093/icesjms/fsr188
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2012
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Identifying blue whiting ( Micromesistius poutassou ) stock structure in the Northeast Atlantic by otolith shape analysis
    Canadian Science Publishing ; 2016
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 73, No. 9 ( 2016-09), p. 1363-1371
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 73, No. 9 ( 2016-09), p. 1363-1371
    Abstract: Information on stock identification and spatial stock structure provide a basis for understanding fish population dynamics and improving fisheries management. In this study, otolith shape analysis was used to study the stock structure of blue whiting (Micromesistius poutassou) in the northeast Atlantic using 1693 samples from mature fish collected between 37°N and 75°N and 20°W and 25°E. The results indicated two stocks located north and south of ICES Divisions VIa and VIb (54°5N to 60°5N, 4°W to 11°W). The central area corresponds to the spawning area west of Scotland. Sampling year effects and misclassification in the linear discriminant analysis suggested exchanges between the northern and southern stocks. The results corroborate previous studies indicating a structuring of the blue whiting stock into two stocks, with some degree of mixing in the central overlap area.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/cjfas-2015-0332
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2016
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    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
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  • 3
    Online Resource
    Online Resource
    Different surveys provide similar pictures of trends in a marine fish community but not of individual fish populations
    Oxford University Press (OUP) ; 2004
    In:  ICES Journal of Marine Science Vol. 61, No. 3 ( 2004-01-01), p. 351-362
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 61, No. 3 ( 2004-01-01), p. 351-362
    Abstract: Choice of sampling method and survey period can have an important impact on the perception of the structure and dynamics of an ecological community. For the Celtic Sea fish assemblage we compared data obtained by three different trawl surveys: an autumn groundfish survey with a GOV trawl, and a spring and an autumn groundfish survey, both carried out with a Portuguese high-headline trawl. Time-series of abundance estimates were not consistent among surveys for all species and were generally very noisy. An analysis of variance components showed that the sampling method contributed more to the variance in abundance estimates compared to survey period, interannual variability, or even sampling variance. Overall community assessments based on indicators such as proportions of non-commercial and piscivorous species, and the proportion of benthic species showed similar trends for all data series. The shape of the size spectrum based on abundances per length class summed over all fish species, although stable over time, was highly sensitive to the sampling method. With the exception of size spectra, community indicators for marine fish assemblages monitored by surveys seem to be robust to survey period and trawling gear, but species abundance trends are method dependent.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1016/j.icesjms.2004.01.004
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2004
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    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
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