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  • 1
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A detailed analysis of beak length to body size and mass measurements was carried out for the glacial squid Psychroteuthis glacialis, which is an endemic cephalopod species in the Southern Ocean. Beak lengths (lower rostral length) were measured from 211 specimens which had been sampled in the Atlantic sector of the Southern Ocean. The basic idea was to find some calibration model in order to inter- or extrapolate missing mantle length and/or wet body mass data by means of beak lengths. The relationships between beak length and mantle length/wet body mass bear essential information for future use in biomass estimates in Southern Ocean top predators, since beaks of P. glacialis occur frequently in the stomach contents of Antarctic seabirds, seals and toothed whales. Therefore, lower rostral lengths were plotted against both mantle length and wet body mass to determine the relationship between these variables. The relationships had limited scatter and very high coefficients of determination, showing that lower rostral length is a good predictor of the squid's mantle length and wet mass. A non-linear 3rd order polynomial regression of lower rostral length against mantle length was identified as the best fitted calibration model, explaining 93% (R 2) of the associated variance. The relationship between lower rostral length and wet body mass was empirically well fitted through regressing ln-transformed values of lower rostral length against wet body mass, explaining 95% (R 2) of the associated variance. The present investigation provides measurements for a wide size range of P. glacialis individuals compared to earlier studies, which were limited on very small data sets.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2016-01-13
    Description: Optic technologies and methods/procedures are established across all areas and scales in limnic and marine research in Germany and develop further continuously. The working group “Aquatic Optic Technologies” (AOT) constitutes a common platform for knowledge transfer among scientists and users, provides a synergistic environment for the national developer community and will enhance the international visibility of the German activities in this field. This document summarizes the AOT-procedures and -techniques applied by national research institutions. We expect to initiate a trend towards harmonization across institutes. This will facilitate the establishment of open standards, provide better access to documentation, and render technical assistance for systems integration. The document consists of the parts: Platforms and carrier systems outlines the main application areas and the used technologies. Focus parameters specifies the parameters measured by means of optical methods/techniques and indicates to which extent these parameters have a socio-political dimension. Methods presents the individual optical sensors and their underlying physical methods. Similarities denominates the common space of AOT-techniques and applications. National developments lists projects and developer groups in Germany designing optical hightechnologies for limnic and marine scientific purposes.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
    Format: application/pdf
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  • 3
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    In:  joachim.groeger@vti.bund.de | http://aquaticcommons.org/id/eprint/2960 | 1240 | 2011-09-29 18:04:59 | 2960 | Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei
    Publication Date: 2021-06-30
    Description: Folgende Kernbehauptungen bzw. Hypothesen werden in dem Worm-et-al.-Artikel aufgestellt:-Der Verlust an Biodiversität (Artenzahl) in einem Meeresgebiet reduziert tief greifend seine Produktivität und seine Stabilität in Stressperioden, hervorgerufen u.a. durch Überfischung und Klimaänderung.-Die Zahl der kollabierten Arten nimmt zu. Dieser Trend projeziert den Kollaps aller wildlebenden Arten und Bestände, die gegenwärtig befischt werden, auf das Jahr 2048.-Diese Entwicklung ist zum gegenwärtigen Zeitpunkt reversibel, denn das Meer besitzt noch ein großes Potential sich zu regenerieren. Dazu ist aber mehr Umweltschutz notwendig.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung - Information on Fishery Research in 2010.
    Keywords: Fisheries ; sustainable fisheries ; comment
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 1-8
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  • 4
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    In:  joachim.groeger@vti.bund.de | http://aquaticcommons.org/id/eprint/3134 | 1240 | 2012-11-10 14:00:26 | 3134 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-25
    Description: Die Einführung gebietsfremder Arten ohne Berücksichtigung ihrer Auswirkungen auf das Nahrungsgefüge ist zurzeit deshalb ein sowohl politisches als auch wissenschaftliches Diskussionsthema, weil sie in der Vergangenheit unerwünschte Auswirkungen hatte. In Seegemeinschaften und isolierten Flusssystemen können eingeführte Arten sogar gravierende Veränderungen verursachen (Townsend 1991). Da diese negativen Auswirkungen zum Teil erst viel zu spät entdeckt worden sind und das Ausmaß allgemein unterschätzt worden ist, muss vor dem Hintergrundeiner verantwortungsvollen Nutzung betroffener Ökosysteme - beruhend auf den Grundsätzen von Nachhaltigkeit und Umweltvorsorge – die Einführung gebietsfremder Arten neu bewertet werden.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.
    Keywords: Environment ; invasive alien species ; ecosystem alterations ; North Sea ; Baltic Sea
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 3-8
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  • 5
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    In:  joachim.groeger@vti.bund.de | http://aquaticcommons.org/id/eprint/3252 | 1240 | 2012-11-10 14:37:24 | 3252 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-26
    Description: Age reading by use of otoliths is one of the basic butalso most essential elements in practical fish populationdynamics. Unfortunately, many factors can influence thereadings of a single reader. Erronous readings, however,have a consequential effect on the evaluation andprediction of the development of the fish stock underconsideration. In order to master this problem and toreduce out the effect of those factors, it seems neccessaryto standardize the whole process of age readingbetween collaborating readers. From a statistical pointof view calibration techniques can be used to identifythose factors and to correct the readings with respect tothem. The current article presents an overview over thebasic idea behind this, over how to balance out the existingdeviations and how to correct the age readings.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010.
    Keywords: Education ; Fisheries ; modelling ; otoliths ; methods
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 84-90
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  • 6
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    In:  joachim.groeger@vti.bund.de | http://aquaticcommons.org/id/eprint/3304 | 1240 | 2012-11-10 17:37:48 | 3304 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-27
    Description: Since years the International Herring Larvae Survey Program (IHLS) is an important and internationally established survey program in the North Sea. The IHLS serves the calibration of stock abundance estimates based on information from the commercial fishery and the method of Integrated Catch Analysis (ICA) which is a specific derivate of the Virtual Population Analysis (VPA). Meanwhile the IHLS database has been transferred from Aberdeen to Kiel and it has been agreed that the Institut für Meereskunde Kiel should continue to maintain this database and provide the abundance indices to be utilized by the ICES Herring Assessment Working Group as one of the means for assessing the state of the herring stock in the North Sea. For establishing the calculation procedure at Kiel, it was necessary to optimize both, the survey designand the index calculation. This article gives an overviewover the survey’s history, it’s geography, the samplingdesign, the information content of the IHLS data base and the various methods of calculating the different indices necessary for the calibration.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010.
    Keywords: Fisheries ; stock assessment ; recruitment ; reproduction ; Planktonsampler ; herring ; larvae ; Baltic Sea
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 29-33
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  • 7
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    In:  joachim.groeger@vti.bund.de | http://aquaticcommons.org/id/eprint/2950 | 1240 | 2011-09-29 18:10:00 | 2950 | Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei
    Publication Date: 2021-06-30
    Description: Though the stocks of North Sea herring seemed to have recovered from small numbers since the mid-1990s we do recently observe a new decline in the spawning stock biomass. This is mainly caused by four consecutive years of small reproduction. Whilst the adults produce enough eggs and larvae only few survive until mature stages. The reasons for the bad recruitment are not clear. In this paper we investigate the influence of climate conditions, in particular the North Atlantic Oscillation (NAO) that obviously triggers the interaction between the size of the spawning stock and the abundance of larvae. We show that approximately 60 % of the recruitment variance can be explained by specific constellations of spawning stock size and climatic conditions. Beside physical factors we also discuss several working hypotheses shedding light on the influence of biological variables on the fluctuation of herring offspring.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung - Information on Fishery Research in 2010.
    Keywords: Fisheries ; Clupea harengus ; recruitment ; herring stock
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 13-21
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  • 8
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    In:  joachim.groeger@vti.bund.de | http://aquaticcommons.org/id/eprint/4209 | 1240 | 2012-11-10 18:42:23 | 4209 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-30
    Description: In order to carry out the Multi-annual Guidance Programmes (MGP) the national fishing fleets of the EU were divided into mostly homogenous fleet segments. The current paper describes the single segments of thc German fishing fleet and summarizes their characteristics such as vessel capacity (tonnage in GRT), machine performance (power in kW) and vessel size (total length in m). Another table lists the averaged landings separated per stock and segment for the period from 1990 to 1994.
    Description: Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010
    Keywords: Fisheries ; stock management ; fisheries management ; regulations ; sustainable fisheries
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 155-158
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