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Waterstraat, A. (1989). Eisfluss eines Gewässerausbaus auf eine Population des Bachneunauges Lampetra planeri (BLOCH, 1784) in einem Flachlandbach im Norden der DDR (Vol. 1).
Schlüsselwörter: Gewässerausbau, Population, Bachneunauge, Lampetra planeri, Flachlandbach, DDR
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Wanzenböck, J., Kovacek, H., & Herzig-Straschil, B. (1989). Zum Vorkommen der Gründlinge im Österreichischen Donauraum (Vol. 42).
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Wanzenböck, J., & Kovacek, H. (1989). Gründlinge im oberen Donauabschnitt: zwei weitere Arten? (Vol. 1).
Schlüsselwörter: Fisch, Donau, Bestimmung, Gobio, Gründling
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Wang, Y. G., & Thomas, M. R. (1995). Accounting for individual variability in the von Bertalanffy growth model (Vol. 52).
Zusammenfassung: Estimation of von Bertalanffy growth parameters has received considerable attention in fisheries research. Since Sainsbury much of this research effort has centered on accounting for individual variability in the growth parameters. In this paper we demonstrate that, in analysis of tagging data, Sainsbury's method and its derivatives do not, in general, satisfactorily account for individual variability in growth, leading to inconsistent parameter estimates (the bias does not tend to zero as sample size increases to infinity). The bias arises because these methods do not use appropriate conditional expectations as a basis for estimation.
Schlüsselwörter: Fisch, Statistik, Methode, Vergleich, Wachstum, Bertalanffy, Faben
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Walters, C., & Ludwig, D. (1994). Calculation of Bayes posterior probability distributions for key population parameters (Vol. 51).
Zusammenfassung: The Bayes posterior probability distribution is a powerful way to represent uncertainty in fisheries stock assessments, and can be calculated for key population and policy parameters of practically any population dynamics model. But the calculation is unwieldy when probabilities are to be assigned to a large grid of parameter combinations. The computational burden can be reduced substantially by analytically integrating over at least two “nuisance parameters” that occur in most assessment models: the observation error variance and the catchability coefficient. This simplification allows the analyst and manager to focus more easily on population parameters (stock size, slope of recruitment curve) that are of direct policy interest.
Schlüsselwörter: Fisch, Fischerei, Statistik, Population, Mathematik, CPUE, VPA, Modell
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Walters, C. (1995). Estimation of historical stock sizes and recruitment anomalies from relative abundance time series (Vol. 52).
Zusammenfassung: Often only simple relative abundance time series and basic growth and (or) survival estimates are available for assessing impacts of fishing and environmental factors. Assessment then involves fitting production models to the series, while forcing the model with observed catch or effort series. A key uncertainty in this approach is how to deal with recruitment variations due to factors other than stock size. A dynamic programming algorithm can be used to compute maximum likelihood estimates of the recruitment anomaly sequence, given prior knowledge of growth parameters, the natural survival rate, and proportion of the variation in the relative abundance index that is due to abundance measurement errors.
Schlüsselwörter: stock-assessment; approximation-; anomalies-; recruitment-; abundance-; growth-; survival-; algorithms-; fishery-management; marine-fisheries
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Walter, U. (1993). Wachstum und Nahrungsökologie von Schleie (Tinca tinca L.) und Hecht (Esox lucius) im Osterholzweiher (Süd-Wüerttemberg. Tübingen: Universität.
Schlüsselwörter: Fisch, Schleie, Tinca tinca, Hecht, Esox lucius, Wachstum, Nahrung
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Walter, E. (1910). Der Flußaal. Neudamm: Verlag J. Neumann.
Schlüsselwörter: Fisch, Aal, Anguilla anguilla, Gesamtwerk
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Walter, B. (1986). Untersuchung der aquatilen Fauna des Stockweihers bei Wolfegg im Vergleich mit zwei weiteren unterschiedlich genutzten Weihern. Hohenheim: Universität.
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Waldmann, J. (1961). Untersuchungen an Heringslarven und Zooplankton des Greifswalder Boddens in den Jahren 1958 und 1959 (Vol. 10 NF).
Schlüsselwörter: Nahrung, Alter, Wachstum, Wanderung
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