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Hiramatsu, K., Akamine, T., & Kitada, S. (1995). Effectiveness of partial likelyhood of estimating fish mortality rates from tag recoveries and the stock composition in the mixed population based on genetic data.
Zusammenfassung: Because of the simplicity of calculation and the availability of evaluating the precision of the estimates, a partial likelihood approach has been used for estimating fish mortality rates from tag recoveries and the stock composition in the mixed population based on genetic data. We compare the partial likelihood estimator with the full likelihood estimator, and find that under some conditions, both estimators are the same. The above applications meet the conditions and hence the estimates using the partial likelihood are the same as the ones using the full likelihood. In this case, the partial likelihood approach is quite useful.
Schlüsselwörter: stock-assessment; tagging-; genomes-; fishing-mortality; mixing-ratio; mathematical-analysis
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Horbowy, J. (1994). Generalized linear models -- ammodern tool for statistical analysis.
Zusammenfassung: Generalized linear models are presented. It is shown how the assumptions of classical linear regression and analysis of variance may be relaxed using the GLM method. An example of a simple analysis of data using the GLIM computer package is also presented.
Schlüsselwörter: fishery-statistics; statistical-analysis; mathematical-models
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Mertz, G., & Myers, R. A. (1995). Estimating the predictability of recruitment (Vol. 93).
Zusammenfassung: A simple analytical technique is developed for estimating the predictability of recruitment, that is, correlations between recruitment and stage-specific mortalities or abundances. The method requires the input of estimates of the variability of stage-specific mortalities, which may be calculated from mean stage-specific mortalities by applying a published regression. It is shown that modification of this regression to compensate for sampling error in field measurements of abundance significantly reduces the estimated standard deviation of log-recruitment, which is an important factor in the predictability calculations. It is concluded that the prospects for predicting recruitment from egg or larval surveys or from environmental variables are quite poor for fish stocks showing the typical distribution of mortality across stages.
Schlüsselwörter: recruitment-; mortality-; developmental-stages; fishery-biology; fishery-management; environmental-factors; stock-assessment; Pisces-; population-dynamics; models-
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Pauly, D., Prein, M., & Hopkins, K. D. (1993). Multiple regression analysis of aquaculture experiments based on the “extended gulland-and-holt plot”: Model derivation, data requirements and recommended procedures.
Zusammenfassung: A method for the multivariate analysis of fish growth in aquaculture is presented. It is derived from a linearized version of the von Bertalanffy growth function (VBGF), which, in its original form, is a bivariate regression termed the Gulland-and-Holt plot. Here, a version in form of a multiple regression equation is presented. The “extended Gulland-and-Holt plot” permits to identify and quantify the key variables controlling fish growth and permits the inclusion of these environmental and treatment variables to explain variance in growth of fish. Von Bertalanffy growth parameters K and L sub( arrow left ) are obtained, which contain the combined environmental effects on fish growth and reflect the range of culture conditions. By computing the index of growth performance ( Phi '), the obtained regression models can be used for growth prediction and decisionmaking in fish farm management and production under a wide range of environmental and management conditions. Recommendations for the design of experiments, preparation of data for analysis and actual analysis procedures are given.
Schlüsselwörter: fish-culture; freshwater-aquaculture; Oreochromis-; multivariate-analysis
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Porch, C. E. (1995). Trajectory-based approaches to estimating velocity and diffusion from tagging data (Vol. 93).
Zusammenfassung: Several new models are developed to estimate the velocity and diffusion of a population from tagging data. The new estimators apply the inverse principle to the individual trajectories of recovered tags rather than to their local abundance. These models require fewer assumptions and less information than do published abundance-based methods. Techniques are presented for a variety of circumstances, and both discrete and continuous parameterizations of the velocity field are included. The sensitivity of the estimators to violations of the assumptions was examined numerically by using stochastic simulations. The results suggest that the estimators are fairly robust but may fail under certain conditions. Extensions to accommodate these situations are discussed.
Schlüsselwörter: dispersion-; migrations-; tagging-; Pisces-; swimming-; models-; dispersal-; migration-
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Quartly, G. D. (1995). Altimeter repeat-track analysis -- a comparison of various algorithms for producing the mean profile (Vol. 12).
Zusammenfassung: Sea surface height may be measured by a satellite-borne altimeter and its along-track slope used to infer geostrophic currents. A major difficulty is that, in general, the local geoid and satellite orbit are not known to the accuracy desired. Thus, comparison is often made between repeat flights of an altimeter along fixed ground tracks in order to infer the changes in the currents. In practice, it is convenient to calculate a mean height profile from many repeat passes and use this as a reference, so that individual altimetric profiles yield variations about this mean. It is thus important to derive a high-quality reliable estimate of the altimetric mean in order to minimize the errors in the inferred flows for the individual repeats. This work examines various methods for deriving the mean profile.
Schlüsselwörter: dynamical-oceanography; remote-sensing; satellite-altimetry; sea-level-measurement; geoid-; geostrophic-transport; statistical-analysis; errors-
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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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Arnason, A. N., & Mills, K. H. (1987). Detection of handling mortality and its effects on Jolly-Seber estimates for mark-recapture experiments (Vol. 44).
Zusammenfassung: Handling mortality occurs in mark-recapture experiments if animals handled and released in a given sample have a higher mortality rate than animals that were alive but not sampled. This violates the assumption of equal survival required for forming the Jolly-Seber estimates of population abundance, survival, and recruitment. The authors show that handling mortality can produce very large biases in these estimates, and we develop a test to detect it. They investigate the power of this test and find that quite large biases can be produced at handling mortality rates that are too low to be detected. They also recommend methods to prevent handling mortality from occurring in fish sampling experiments and methods to reduce bias in the estimates. The test and the bias corrections are applied to mark-recapture data for a lake whitefish (Coregonus clupeaformis ) population and to data from simulated mark-recapture experiment.
Schlüsselwörter: Fischerei, Statistik, Mathematik, Modell, Mortalität, Jolly-Seber
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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: fischerei, Population, Mathematik, Modell, Statistik, CPUE
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Gaschütz, G., Pauly, D., & David, N. (1980). A versatile BASIC program for fitting weight and seasonally oscillating length growth data.
Schlüsselwörter: Statistik, wachstum, methode, formeln, theorie, basic, listing
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