Reger, K. H. (1987). Über die Flußperlmuschel.
Schlüsselwörter: muscheln, artenschutz
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Labelle, M. (1994). A likelihood method for estimating Pacific salmon escapement based on fence counts and mark-recapture data (Vol. 51).
Zusammenfassung: Pacific salmon (Oncorhynchus spp.) escapements in natural streams are often determined by conducting fence counts in conjunction with mark-recapture operations. Typical field conditions are characterized by protracted floods, undetected immigration, variation in sampling rates, mortality during the census periods, small sample sizes, and few successive recaptures. Closed population models tend to overestimate escapement under such conditions, and traditional open population models cannot always be relied on due to the lack of sufficient data. A likelihood-based estimation method was specifically designed for such conditions. A distinguishing feature of this model is that individual recapture histories are not required for parameter estimation. The model is also structured to incorporate ancillary data in the estimation process to improve the precision and accuracy of the estimates. The model is described in detail, and suggestions are made to facilitate its application.
Schlüsselwörter: capt-recapt, methode, ML, modell, statistik, simulation
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McGarvey, R. (1994). An age-structured open-access fishery model (Vol. 51).
Zusammenfassung: A dynamic model for open-access fisheries is presented. In addition to density dependence in recruitment and fishing effort changing in proportion to the level of profit fishermen earn which characterizes previous open-access models, it incorporates full age structure for the fish stock, lognormal environmental recruitment variability, and gear selectivity. The predator-prey cycling solution of the original Schaefer dynamic model, and subsequent open-access models, persists for these model extensions. Density dependence in recruitment induces greater global stability. Environmental recruitment variability, common in marine populations, is destabilizing in the neighborhood of the open-access equilibrium. Approximating model steady states of effort and catch by the corresponding averages from data time series underlies a new algorithm of parameter evaluation, applied here to an open-access model of the Georges Bank sea scallop (Placopecten magellanicus) fishery.
Schlüsselwörter: modell, statistik, population, dynamik, algorithmus
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?. Clusteralgorithmen: Hierarchische Verfahren.
Schlüsselwörter: statistik, methode, fortran, listing, algorithmen, cluster
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Conway, G. R., Glass, N. R., & Wilcox, J. C. (1970). Fitting Nonlinear Models to Biological Data by Marquardt´s Algorithm (Vol. 51).
Zusammenfassung: Equations describing biological phenomena frequently have parameters entering nonlinearly. A highly efficient method for detemining the values of parameters in such equations that will give the best least-squares fit to a set of data is Marquardt´s algorithm. A step-by-step derivation of the algorithm is given in terms that require only the knowledge of elementary calculus and matrix algebra. As an example, the method is used to fit the logistic equation to a set of data.
Schlüsselwörter: marquardt, statistik, methode, nichtlinear, algorithmus
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Kenchington, E. L., & Full, W. E. (1994). Fourier analysis of sea scallop (Placopecten magellanicus) shell in determining population structure (Vol. 51).
Zusammenfassung: Sea scallops (Placopecten magellanicus) were sampled from each of four scallop beds: the northeast peak of Georges Bank, Western Bank, St. Pierre Bank, and the Bay of Fundy near Digby, N.S. The outlines of scallop top shells were captured by video imagery using a semiautomated approach. Fourier shape descriptors were calculated and analyzed. Age and year-class effects were shown to be important factors influencing scallop shell shape. Allometric effects on Fourier harmonics also have a significant influence on shell shape in this species. Comparisons of Fourier harmonics between scallop beds separated by age and sampling year, and corrected for allometry, revealed significant differences in the majority of harmonic numbers.
Schlüsselwörter: population, fourier, statistik, methode, modell, wachstum, muscheln
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Marquardt, D. W. (1963). An algorithm for Least-Squares Estimation of Nonlinear Parameters (Vol. 11).
Zusammenfassung: The algorithm discribed shares with the gradient methods their ability to converge from an initial guess which may be outside the region of convergence of other methods. The algorithm shares with the Taylor series method the ability to close in on the converged values rapidly after the vicinity of the converged values has been reached. Thus, the method combines the best feutures of ith predecessors while avoiding their most serious limitations.
Schlüsselwörter: mathematik, marquardt, nichtlinear, methode, algorithmus
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Hradetzky, J. (1978). Ein effizientes Schätzverfahren für einige nichtlineare Regressionsmodelle.
Zusammenfassung: An intrinsically linear regression model can be expressed, by suitable transformation of the variables, in the standard linear form, so that the parameters can be estimated by the OLS-method. In this way the residual sum of squares for the transformed model, but not for the original, in minimized. In this paper a weighted least squares method for avoiding these disadvantages is discussed.
Schlüsselwörter: mathematik, regression, methode, schätzung
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Ricker, W. E. (1975). Vital Statistics from Marking: Single Season Experiments (0thVol. 191). Ottawa: Department of the Environment, Fischeries and Marin Service.
Schlüsselwörter: statistik, capt-recapt, methode, Grundlage
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Cadigan, N. G., & Shelton, P. A. (1993). SAS programs for fitting a seal population dynamics model.37.
Zusammenfassung: This technical report presents a description of two SAS programs (MAKED.SAS and SEAL.SAS) that fit a population dynamics model to seal (Phocidae) data. The programs have been constructed in such a manner that special knowledge of SAS is not required to run them. The population dynamics model is transformed to a standard nonlinear regression model and parameters are estimated using SAS's PROC NLIN. Output from the programs includes estimates of intrinsic mortality, pup numbers over time and total population numbers over time. The code for the programs is presented along with two examples.
Schlüsselwörter: SAS, population, saison, mortalität, modell
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