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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Francis, R. I. C. C. (1990). Back-calculation of fish length: A critical review (Vol. 36).
Zusammenfassung: A review is made of the literature on the back-calculation of fish body length from marks on scales or other hard parts (otoliths, vertebrae, fin rays, etc.). Though the technique is widely used it does not appear to be well understood. Regression methods are commonly used, apparently in ignorance of the more realistic proportional methods. It is not generally recognized that there are two equally plausible back-calculation hypotheses which can lead to significantly different back-calculated lengths. The Fraser-Lee equation, the most commonly used back-calculated formula, follows neither of these hypotheses but is based on a misuse of linear regression. It is recommended that back-calculation be restricted to procedures following one of the proportional hypotheses; that the difference between lengths calculated using the two hypotheses is a useful measure of the minimum uncertainty in back-calculation lengths; and that more attention be paid to validating back-calculation hypotheses by comparing observed and back-calculated lengths for individual fish. The pattern of heteroscedasticity in body length-scale radius plots is noted as a useful diagnostic in evaluating back-calculation hypothesis.
Schlüsselwörter: Fisch, Statistik, Regression, Längen..., Review, Wachstum
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Criddle, K. R. (1991). Modelling dynamic fish populations. Seattle, WA (USA): National Marine Fisheries Serv.
Zusammenfassung: A recently introduced multivariate state-space time-series modeling algorithm, system-theoretic time-series, can be used to create a particularly robust state-space representation. Combining the model approximation methodology with time-series modeling of the residuals in accurate models of short-run dynamics. The approximate structural modeling methodology is illustrated with single species models of yellowfin sole (Limanda aspera ) biomass, and multispecies models of Pacific halibut (Hippoglossus stenolepis ), yellowfin sole, and red king crab (Paralithodes camtschatica ) biomasses in the eastern Bering Sea. A final application of the approximate structural/system-theoretic time-series model includes walleye pollock (Theragra chalcogramma ), Pacific halibut, Pacific cod (Gadus macrocephalus ), yellowfin sole, and red king crab. (Prepared in cooperation with Alaska Univ., Fairbanks.)
Schlüsselwörter: fishery-biology; commercial-species; Limanda-aspera; Hippoglossus-stenolepis; Paralithodes-camtschatica; Theragra-chalcogramma; Gadus-macrocephalus; mathematical-models; biomass-; INE,-USA,-Alaska
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Trent, L., Palko, B. J., & Trimble, A. (1987). Improved Method of Measuring Length of Large Samples of Fish (Vol. 49).
Zusammenfassung: A new method to record fish lengths is described. Its advantages include quick recording of large numbers of fish by one person, accurate measurements by inexperienced personnel, easy transmission of data, low expense, usability under harsh field conditions, and easy transportability.
Schlüsselwörter: Methode, fischerei
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Stamatopoulos, C., & Caddy, J. F. (1989). Estimation of von Bertalanffy growth parameters: A versatile linear regression approach (Vol. 45).
Zusammenfassung: A new linear regression method is presented for fitting the von Bertalanffy growth function to data on size at age, which is also applicable to tag and recapture data. From tests on simulated data the method shows lower error and bias and more flexibility of action than other commonly used methods.
Schlüsselwörter: Fischerei, statistik, modell, wachstum
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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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Levin, J. Z. (1988). A rational parametric approach to latitude, longitude, and altitude (Vol. 35).
Zusammenfassung: A method for parametrically representing the surface of the earth is described. Latitude and longitude are replaced by parametric pseudolatitude and pseudolongitude. Conversions between Cartesian coordinates in three-space and the parametric form are described. A compact and precise algorithm for cartesian-to parametric form has been developed by way of tested computer procedures.
Schlüsselwörter: mapping-; map-projections; coordinate-systems; cartography-; latitude-; longitude-; height-
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Cole, R., Ward, F., Ward, T., Deitner, R., & Fiore, J. (1987). Model for optimization of socio-economic fishery values on the Rio Grande in New Mexico. New Mexico Water Resources Research Inst., Las Cruces (USA).
Zusammenfassung: A mathematical model which simulates sport-fish production yield and economic value in the Rio Grande basin of New Mexico is described. The model links hydrologic, biologic, and economic components into a mathematical representation of fisheries habitat, fishery dynamics, economic benefits, and income generated by sport-fishing in New Mexico. The model has a research version programmed in FORTRAN. The model users can modify water volume flowing through the basin by month, water stored in each reservoir, water discharged through connecting water material concentrations (suspended solids, total phosphorus, total nitrogen) in the water, site access, and site quality. (Prepared in cooperation with New Mexico State Univ., Las Cruces. Dept. of Fishery and Wildlife Sciences. Sponsored by Geological Survey, Reston, VA (USA). Water Resources Div.)
Schlüsselwörter: economic-models; sport-fishing; fishery-economics; USA,-New-Mexico,-Grande-R.-basin
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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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Dahlberg, M. L. (1978). Computer program for analysis of the homogeneity and goodness of fit of frequency distributions, FORTRAN 4 (Vol. 76).
Zusammenfassung: A computer program was developed which forms frequency distributions from length measurements and then calculates a chi-square statistic which is used to test the homogeneity of the frequencies for the purpose of pooling. Output includes listing of arithmetic mean, variance, standard deviation, standard error of the mean, total sample size, and chi-square statistic of goodness of fit for individual groups and for the pooled frequency distribution. Histograms of all frequency distributions are produced as full-page printer charts, scaled if necessary to 50 units by up to 100 class intervals. The pooled frequencies and class midpoints are punched on cards to facilitate additional analyses. The program was developed on an IBM 360/65 OS System and required 56,811 bytes of storage.
Schlüsselwörter: computer-programmes; population-structure
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