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  • 1
    Type of Medium: Book
    Series Statement: ICES council meeting papers 1996(7)
    Language: Undetermined
    Note: Zugl.: ICES council meeting papers : C
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  • 2
    Keywords: Hochschulschrift
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (96 Seiten = 11 MB) , Graphen, Karte
    Edition: 2020
    Language: German
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  • 3
    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
    Type of Medium: Online Resource
    Pages: graph. Darst
    ISSN: 0165-7836
    Language: English
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  • 4
    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
    Description / Table of Contents: 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.
    Type of Medium: Electronic Resource
    ISSN: 0078-3234
    Language: English
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  • 5
    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
    Description / Table of Contents: 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.
    Type of Medium: Online Resource
    Pages: graph. Darst.
    ISSN: 0924-7963
    Language: English
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  • 6
    In: Deep-sea research / 2, 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
    Description / Table of Contents: 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.
    Type of Medium: Online Resource
    Pages: graph. Darst
    ISSN: 1879-0100
    Language: English
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  • 7
    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
    Description / Table of Contents: 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.
    Type of Medium: Online Resource
    Pages: graph. Darst.
    ISSN: 1365-2419
    Language: English
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Ocean dynamics 39 (1986), S. 35-40 
    ISSN: 1616-7228
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary An investigation is described which examines the influence of long-term storage on the salinity of bottled seawater samples in common soft glass bottles. Two experiments were carried out over independent time periods, the first one covering 7 months and the second one 16 months. The results show that long-term storage increases mean salinity and variance. During the first 6 months a rate of change of about 0.0012 in 30 days is observed. After that time the rate of change decreases to about 0.0004 per 30 days. The observed curve is interpreted as desorption of glass components into the seawater sample. Evaporation and the influence of efficient biological activities can be excluded confidently. For the salinity sample bottles used in the physical laboratories in Kiel the results make long-term stored salinity samples inappropriate for accurate in-situ calibration of modern CTD devices. The details of the chemical reactions were not investigated.
    Type of Medium: Electronic Resource
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  • 9
    Publication Date: 2023-01-31
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
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  • 10
    Publication Date: 2023-01-31
    Description: Variations in oxygen conditions below the permanent halocline influences the Baltic ecosystem through a number of mechanisms. Principle among these are fluctuations in the availability of benthic habitat suitable for Baltic cod (the top predator in the Baltic ecosystem). Variations in the volume of deep oxygenated water influences dircetly the potential feeding habitat and volume of water suitable for spawning. Recent research has identified the importance of inflows of saline, oxygen rich North Sea water into the Baltic sea on the recruitment success of Baltic cod. These inflows increase the volume of water with suitable oxygen and salinity conditions for the development and survival of cod eggs (termed spawning volume). Increases in the "spawning volume" have occurred with out the occurrence of a major inflow from the North Sea (e.g. 1958-59; 1966-67). Other candidate processes suggested to potentially increase the "spawning volume" include variations in timing and volume of terrestrial runoff, advection of water from the Arkona Basin, convective overturning of the water column due to surface cooling as well as wind mixing down to the halocline. In order to examine the latter three mechanisms, we have performed model simulations utilizing the Baltic Sea Model (Lehmann, 1995). Three-dimensional fields of temperature and salinity were obtained from field studies in July 1995 and interpolated onto the model grid, atmospheric forcing data was obtained from EUROPA-Model. The BaItic Sea model was then run from the period from July 24 to December 31, 1995. To test the effects of increased wind energy and surface cooling on oxygen conditions below the permanent halocline variations in the oxygen conditions were examined utilizing the following experiment conditions; a) a reduction of SST by 5 oe over the entire simulation period thereby increasing vertical convection. b) an increase of surface wind energy over the modeled period by 15%. c) two high energy winter storms The results of these simulations and the possible implications of the effects of these processes on the reproductive environment of Baltic cod will be discussed.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
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