| Einträge |
| Autor |
Hradetzky, J. |
| Titel |
Ein effizientes Schätzverfahren für einige nichtlineare Regressionsmodelle |
Typ |
Zeitschrift, Artikel |
| Jahr |
1978 |
Publikation |
Mittlg. Forstl. Vers. u. Forschungsanstalt B.W. |
Kurztitel der Zeitschrift |
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| Band |
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Ausgabe |
91 |
Seiten |
155-161 |
| Schlüsselwörter |
mathematik, regression, methode, schätzung |
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. |
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nein |
| Rufnummer |
474 |
Signatur |
2275 |
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| Autor |
Gascuel, D. |
| Titel |
[A simple adjustment method of age-length keys: Application to yellowfin tuna (Thunnus albacares) catches in the East Atlantic.] |
Typ |
Zeitschrift, Artikel |
| Jahr |
1994 |
Publikation |
Can. J. Fish. Aquat. Sci |
Kurztitel der Zeitschrift |
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| Band |
51 |
Ausgabe |
3 |
Seiten |
723-733 |
| Schlüsselwörter |
fishery-management; stock-assessment; mathematical-models; growth-curves; biological-age; length-; Thunnus-albacares; AE,-East-Atlantic; tuna-fisheries |
| Zusammenfassung |
An adjustment method for age-length keys is presented that incorporates yearly variability in cohort abundances. The method is based on two models (one for growth and the other for standard deviations of length versus age) and involves an iterative algorithm. The algorithm rapidly converges to stable results that yield, under some conditions, maximum likelihood estimates. It is also used to estimate parameters of the length standard deviation model. The method is applied to yellowfin tuna (Thunnus albacares) catches in the eastern Atlantic from 1975 to 1989. |
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Leer |
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480 |
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| Autor |
Ebel, G. |
| Titel |
Beobachtungen im Helmegebiet zur Reproduktion der Barbe |
Typ |
Zeitschrift, Artikel |
| Jahr |
1996 |
Publikation |
Naturschutz im Land Sachsen-Anhalt |
Kurztitel der Zeitschrift |
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| Band |
33 |
Ausgabe |
1 |
Seiten |
21-28 |
| Schlüsselwörter |
Artenschutz, Habitat, Wasserbau, Fisch, Barbe, Barbus barbus, Fortpflanzung |
| Zusammenfassung |
Am Mittel- und Unterlauf der Helme (Sachsen-Anhalt) wurden im Frühjahr 1994 und 1995 drei Laichplätze der Barbe (Barbus barbus L.) aufgefunden, von denen einer durch Sohlräumungsarbeiten im Juli 1995 vernichtet wurde. An den andern beiden Laichplätzen wurden im August 1995 Jungfische nachgewiesen. Gefährdet ist die Barbe vor allem durch wasserbauliche Unterhaltungsmaßnahmen (Böschungsbefestigungen, Beseitigung von Ufergehölzen, Sohlberäumungsmaßnahmen). Der Verfasser beschreibt Reproduktionsverhalten und Habitatansprüche der Barbe und stellt notwendige Schutzmaßnahmen zusammen. |
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381 |
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| Autor |
Akamine, T. |
| Titel |
Estimation of parameter for Richards model |
Typ |
Zeitschrift, Artikel |
| Jahr |
1988 |
Publikation |
Bull. Japan Sea Reg. Fish. Res. Lab. Nissuiken Hokoku |
Kurztitel der Zeitschrift |
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| Band |
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Ausgabe |
38 |
Seiten |
187-200 |
| Schlüsselwörter |
Wachstum, theorie, methode, statistik, listing, basic, modell |
| Zusammenfassung |
Akamine's (1986) BASIC program by Marquardt's method was rewritten for Richards model and its expanded model by the periodic function. For 0.9 similar to 1.1 the “LOG” function is corrected by Taylor series. Data estimated to be negative are cut off. AIC judges the effect of adding n to the parameters. Richards model is not so important in practice but it is important theoretically. |
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206 |
Signatur |
2094 |
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France, R.; Holmes, J.; Lynch, A. |
| Titel |
Use of size-frequency data to estimate the age composition of crayfish populations |
Typ |
Zeitschrift, Artikel |
| Jahr |
1991 |
Publikation |
CAN. J. FISH. AQUAT. SCI. |
Kurztitel der Zeitschrift |
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| Band |
48 |
Ausgabe |
12 |
Seiten |
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| Schlüsselwörter |
Krebs, lÄngenfrequenz, methode, statistik, population |
| Zusammenfassung |
Age-classes in crayfish populations can be determined from size-frequency data provided 4 tents are adhered to only crayfish collected from areas of rock substrate are used; trapping are excluded; species do not have longevities exceeding about 4 yr; and most importantly, sample sizes are greater than about 200. Studies that have failed to follow these guidelines have met with limited success in dissecting mixed frequency distributions. Further, 3 validation procedures must be undertaken: temporal replication within molting events to measure the precision of both data collection and size-frequency analysis; corroboration with known-age crayfish from either field recaptures or laboratory molt increments; and concordance with independent analysis of the mean size at onset of sexual maturity. When these checks support the size-frequency results, population age composition and analyses of rates of growth or mortality can be considered reliable. |
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| Rufnummer |
301 |
Signatur |
2169 |
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Juell, J. E.; Westerberg, H. |
| Titel |
An ultrasonic telemetric system for automatic positioning of individual fish used to track Atlantic salmon (Salmo salar L.) in a sea cage |
Typ |
Zeitschrift, Artikel |
| Jahr |
1993 |
Publikation |
Aquacult. Eng |
Kurztitel der Zeitschrift |
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12 |
Ausgabe |
1 |
Seiten |
1-18 |
| Schlüsselwörter |
telemetrie, fische, methode, technik |
| Zusammenfassung |
A telemetric system for automatic positioning of individual fish in the vertical or horizontal plane is described. The position of a transmitter in a fish is computed from the difference in arrival time of the ultrasonic signal to a fixed array of hydrophones. Sources of error in positioning are discussed. In a preliminary study, the resolution of the system in time and space was adequate to monitor the behaviour of adult salmon in a sea cage. At moderate stocking density the salmon was swimming continually in counter-clockwise circles and diel rhythms in swimming speed, depth and path-radius were observed. With only 30 fish in the cage this stereotype behaviour broke down. Few or no visits into the feeding area during some feedings indicated a variable feeding motivation. |
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nein |
| Rufnummer |
478 |
Signatur |
2279 |
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Mertz, G.; Myers, R. A. |
| Titel |
Estimating the predictability of recruitment |
Typ |
Zeitschrift, Artikel |
| Jahr |
1995 |
Publikation |
Fish. Bull |
Kurztitel der Zeitschrift |
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| Band |
93 |
Ausgabe |
4 |
Seiten |
657-665 |
| Schlüsselwörter |
recruitment-; mortality-; developmental-stages; fishery-biology; fishery-management; environmental-factors; stock-assessment; Pisces-; population-dynamics; models- |
| 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. |
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Zu bestellen |
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1090 |
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Francis, R. I. C. C. |
| Titel |
Back-calculation of fish length: A critical review |
Typ |
Zeitschrift, Artikel |
| Jahr |
1990 |
Publikation |
J. Fish Biol |
Kurztitel der Zeitschrift |
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36 |
Ausgabe |
6 |
Seiten |
883-902 |
| Schlüsselwörter |
Fisch, Statistik, Regression, Längen..., Review, Wachstum |
| 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. |
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Fish. Res. Cent., Box 297, Wellington, New Zealand |
Geprüft |
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530 |
Signatur |
2329 |
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Espanhol, Rute; Almeida, Pedro R.; Alves, M. Judite |
| Titel |
Evolutionary history of lamprey paired species Lampetra fluviatilis (L.) and Lampetra planeri (Bloch) as inferred from mitochondrial DNA variation |
Typ |
Journal Article |
| Jahr |
2007 |
Publikation |
Molecular Ecology |
Kurztitel der Zeitschrift |
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16 |
Ausgabe |
9 |
Seiten |
1909 - 1924 |
| Schlüsselwörter |
Neunauge, Bachneunauge, Lampetra planeri, Flussneunauge, Lampetra fluviatilis, DNA, Phylogeographie |
| Zusammenfassung |
A remarkable trend in the evolution of lampreys is the occurrence in most genera of 'paired species', in which the parasitic anadromous lampreys are believed to have given rise to nonparasitic freshwater resident populations. The present work examines the phylogeography of the European paired species Lampetra fluviatilis and Lampetra planeri, in an attempt to elucidate species pair evolutionary history. We studied sequence variation in cytochrome b and ATPase 6, 8 mitochondrial genes in 63 individuals from 21 localities of the paired species throughout their distribution range. Results from the phylogenetic and nested clade analyses were largely consistent, suggesting the existence of three major evolutionary lineages: lineage I and possibly lineage II are widespread throughout Europe, while the most ancestral lineage III is apparently restricted to the Iberian Peninsula. The high genetic diversity observed in the Iberian Peninsula is probably the result of refugial persistence and subsequent accumulation of variation over several ice ages, whereas the low levels of genetic diversity observed in central and northern Europe should reflect a rapid postglacial colonization. Results suggest that L. planeri originated within at least two distinct evolutionary lineages, rejecting the single origin hypothesis. The observed lack of taxa monophyly within lineage I may be the result of ongoing gene flow if the two taxa are alternate life-history forms of a single species. However, structure within lineage I is also consistent with the hypothesis of divergence of taxa after postglacial dispersion (around 2000 generations ago) with incomplete lineage sorting. Further testing of the alternative hypotheses is warranted. |
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en |
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nein |
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907 |
Signatur |
2877 |
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| Autor |
Criddle, K. R. |
| Titel |
Modelling dynamic fish populations |
Typ |
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1991 |
Publikation |
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Ausgabe |
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Seiten |
82 |
| Schlüsselwörter |
fishery-biology; commercial-species; Limanda-aspera; Hippoglossus-stenolepis; Paralithodes-camtschatica; Theragra-chalcogramma; Gadus-macrocephalus; mathematical-models; biomass-; INE,-USA,-Alaska |
| 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.) |
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National Marine Fisheries Serv. |
Erscheinungsort |
Seattle, WA (USA) |
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317 |
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