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  • 2020-2024  (7)
  • 2005-2009  (84)
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  • 1
    In: Journal of marine systems, New York, NY [u.a.] : Elsevier, 1990, 74(2008), 1/2, Seite 329-342, 0924-7963
    In: volume:74
    In: year:2008
    In: number:1/2
    In: pages:329-342
    Beschreibung / Inhaltsverzeichnis: We employed a coupled biologicalphysical, individual-based model (IBM) to estimate spatial and temporal changes in larval fish habitat suitability (the potential for areas to support survival and high rates of growth) of the German Bight, southern North Sea. In this Lagrangian approach, larvae were released into a size-structured prey field that was constructed from in situ measurements of the abundance and prosome lengths of stages of three copepods (Acartia spp., Temora longicornis, Pseudocalanus elongatus) collected on a station grid repeatedly sampled from February to October 2004. The choice of prey species and the model parameterisations for larval fish foraging and growth were based on field data collected for sprat (Sprattus sprattus) and other clupeid larvae. A series of 10-day simulations were conducted using 20 release locations to quantify spatialtemporal differences in projected larval sprat growth rates (mm d- 1) for mid-April, mid-May and mid-June 2004. Based upon an optimal foraging approach, modeled sprat growth rates agreed well with those measured in situ using larval fish ototliths. On the German GLOBEC station grid, our model predicted areas that were mostly unsuitable habitats (areas of low growth potential), e.g. north of the Frisian Islands, and others that were consistently suitable habitats (areas that had high growth potential), e.g. in the inner German Bight. In some instances, modelled larvae responded rapidly (~ 5 days) to changing environmental characteristics experienced along their drift trajectory, a result that appears reasonable given the dynamic nature of frontal regions such as our study area in the southern North Sea.
    Materialart: Online-Ressource
    Seiten: graph. Darst.
    ISSN: 0924-7963
    Sprache: Englisch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    In: Fisheries oceanography, Oxford [u.a.] : Wiley-Blackwell, 1997, 16(2007), 3, Seite 207-215, 1365-2419
    In: volume:16
    In: year:2007
    In: number:3
    In: pages:207-215
    Beschreibung / Inhaltsverzeichnis: Otolith increment width and larval fish data (length and weight) were used to develop an individual-based model (IBM) to describe daily resolved growth rates of North Sea herring (Clupea harengus) larvae (Autumn Spawners) caught during International Herring Larvae Surveys in the ICES area IVa from 1990 to 1998. The model combines sagittal otolith readings (core and individual increment measurements), larval standard length and weight data, and solves an over-determined set of linear system equations for all parameters using the method of least square residuals. The model consists of a matrix, which describes the increment width formation of 119 larvae, a vector containing their length/weight measurements, and a vector describing residuals. The solution vector yields age-dependent maximum somatic growth rates of herring larvae up to an age of 41 days with sizes ranging from 10 to 25 mm. The observed environmental temperature in which larvae dwelled was relatively uniform. Therefore, measured increment width was individually used to determine daily growth from any single larva in relation to their potential maximum growth under optimal feeding conditions. The results are discussed with respect to the spatial and temporal variability of larval occurrence. Finally, an analysis of error estimation of the larval growth characteristics is presented.
    Materialart: Online-Ressource
    Seiten: graph. Darst.
    ISSN: 1365-2419
    Sprache: Englisch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: Deep-sea research. Part 2, Topical studies in oceanography, Amsterdam [u.a.] : Elsevier Science, 1993, 56(2009), 21/22, Seite 1968-1983, 1879-0100
    In: volume:56
    In: year:2009
    In: number:21/22
    In: pages:1968-1983
    Beschreibung / Inhaltsverzeichnis: Analysis of the temporal and spatial variability of biological processes and identification of the main variables that drive the dynamic regime of marine ecosystems is complex. Correlation between physical variables and long-term changes in ecosystems has routinely been identified, but the specific mechanisms involved remain often unclear. Reasons for this could be various: the ecosystem can be very sensitive to the seasonal timing of the anomalous physical forcing; the ecosystem can be contemporaneously influenced by many physical variables and the ecosystem can generate intrinsic variability on climate time scales. Marine ecosystems are influenced by a variety of physical factors, e.g., light, temperature, transport, turbulence. Temperature has a fundamental forcing function in biology, with direct influences on rate processes of organisms and on the distribution of mobile species that have preferred temperature ranges. Light and transport also affect the physiology and distribution of marine organisms. Small-scale turbulence determines encounter between larval fish and their prey and additionally influences the probability of successful pursuit and ingestion. The impact of physical forcing variations on biological processes is studied through long-term observations, process studies, laboratory experiments, retrospective analysis of existing data sets and modelling. This manuscript reviews the diversity of physical influences on biological processes, marine organisms and ecosystems and their variety of responses to physical forcing with special emphasis on the dynamics of zooplankton and fish stocks.
    Materialart: Online-Ressource
    Seiten: graph. Darst
    ISSN: 1879-0100
    Sprache: Englisch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Fisheries research, Amsterdam [u.a.] : Elsevier Science, 1981, 91(2008), 1, Seite 1-14, 0165-7836
    In: volume:91
    In: year:2008
    In: number:1
    In: pages:1-14
    Materialart: Online-Ressource
    Seiten: graph. Darst
    ISSN: 0165-7836
    Sprache: Englisch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    In: Oceanologia, Sopot : [Verlag nicht ermittelbar], 1971, 50(2008), 2, Seite 205-220, 0078-3234
    In: volume:50
    In: year:2008
    In: number:2
    In: pages:205-220
    Beschreibung / Inhaltsverzeichnis: Existing coupled biophysical models for Baltic larval cod drift, growth and survival use idealised constructed mean prey fields of nauplius distributions. These simulations revealed the best feeding conditions for Baltic cod larvae longer than 6 mm. For shorter, first feeding larvae (between 4.5 and 6 mm) pronounced differences in growth and survival were observed, which depend on food availability and to a lesser degree on ambient temperature. We performed runs with an Individual-based Model (IBM) for Baltic cod larvae in order to demonstrate how natural variability in prey abundance influences the survival success of first feeding larvae. In the Baltic, this larval stage lives mainly between 20 and 40 m depth and feeds exclusively on the nauplii of different calanoid copepods (Acartia spp., Pseudocalanus acuspes, Temora longicornis and Centropages hamatus). Prey data obtained from vertically stratified samples in the Bornholm Basin (Baltic Sea) in 2001 and 2002 indicate a strong variability at spatial and temporal scales. We calculated larval survival and growth in relation to natural variation of prey fields, i.e. species-specific nauplius abundance. The results of the model runs yielded larval survival rates from 60 to 100% if the mean size of nauplii species was taken and lower survival if prey consisted of early nauplius stages only.
    Materialart: Online-Ressource
    ISSN: 0078-3234
    Sprache: Englisch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Publikationsdatum: 2019-09-23
    Beschreibung: Knowledge of the spatial and temporal distribution of juvenile cod is essential to closing the life cycle in population dynamic models, and it is a prerequisite for the design of Marine Protected Areas (MPAs) aiming at the protection of juveniles. In this study, we use a hydrodynamic model to examine the spatial distribution of eastern Baltic cod larvae and early juveniles. The transport patterns of the larvae spawned at the three major spawning grounds in the central Baltic Sea were investigated by drift model simulations for the period 1979–2004. We analysed potential habitats for their suitability for juvenile settlement, i.e. the change from pelagic to demersal life. The results revealed a clear dependence of the probability for successful settling on wind-induced drift of larval cod, which is controlled by the local atmospheric conditions over the Baltic Sea. Furthermore, we found evidence that the final destinations of juvenile cod drift routes are affected by decadal climate variability. Application of the methodology to MPA design is discussed, e.g. identifying the overlap of areas with a high probability of successful juvenile cod settlement and regions of high fishing effort in small-meshed fisheries targeting sprat and herring.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    facet.materialart.
    Unbekannt
    Instytut Oceanologii Polska Akademia Nauk, Sopot
    In:  Oceanologia, 50 (2). pp. 205-220.
    Publikationsdatum: 2017-02-03
    Beschreibung: Existing coupled biophysical models for Baltic larval cod drift, growth and survival use idealised constructed mean prey fields of nauplius distributions. These simulations revealed the best feeding conditions for Baltic cod larvae longer than 6 mm. For shorter, first feeding larvae (between 4.5 and 6 mm) pronounced differences in growth and survival were observed, which depend on food availability and to a lesser degree on ambient temperature. We performed runs with an Individual-based Model (IBM) for Baltic cod larvae in order to demonstrate how natural variability in prey abundance influences the survival success of first feeding larvae. In the Baltic, this larval stage lives mainly between 20 and 40 m depth and feeds exclusively on the nauplii of different calanoid copepods (Acartia spp., Pseudocalanus acuspes, Temora longicornis and Centropages hamatus). Prey data obtained from vertically stratified samples in the Bornholm Basin (Baltic Sea) in 2001 and 2002 indicate a strong variability at spatial and temporal scales. We calculated larval survival and growth in relation to natural variation of prey fields, i.e. species-specific nauplius abundance. The results of the model runs yielded larval survival rates from 60 to 100% if the mean size of nauplii species was taken and lower survival if prey consisted of early nauplius stages only.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    In:  [Talk] In: ECONORTH-Symposium, 14.03, Tromsö, Norway .
    Publikationsdatum: 2012-02-23
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Publikationsdatum: 2016-02-26
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    facet.materialart.
    Unbekannt
    In:  [Invited talk] In: Workshop on Recruitment Failure of the Baltic Coastal Fish Stocks, 05.09, Öregrund, Sweden .
    Publikationsdatum: 2012-02-23
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Standort Signatur Einschränkungen Verfügbarkeit
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