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Nemec, A. F. L., & Brinkhurst, R. O. (1988). Using the Bootstrap to Assess Statistical Significance in the Cluster Analysis of Species Abundance Data (Vol. 45).
Schlüsselwörter: Fischerei, statistik, cluster, methode, modell
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Weisberg, S. (1993). Using Hard-part Increment Data to Estimate Age and Environmental Effects. Can. J. Fish. Aquat. Sci., 50, 1229?1237.
Schlüsselwörter: Fisch, Alter, Methode, Altersbestimmung, Statistik, Mathematik, Schuppe, Knochenstruktur
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Caputi, N. (1988). Factors affecting the time series bias in stock-recruitment relationships and the interaction between time series and measurement error bias (Vol. 45).
Zusammenfassung: The stock-recruitment relationship (SRR) and the recruitment to spawning stock relationship (RSR) of the tiger prawn (Penaeus esculentus ) in Exmouth Gulf, Western Australia, were used to examine the time series bias and measurement error bias by Monte Carlo simulations. Simulating the effect of measurement error as well as the random variation about the SRR and RSR helps to determine the possible combinations of measurement error and random variation which may result in the observed variation about the SRR and RSR. The simulations also indicate that there is an interaction between measurement error and random variation about the SRR/RSR on the bias of the parameters of the SRR.
Schlüsselwörter: Fischerei, statistik, zeitreihe, methode, modell, theorie
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France, R., Holmes, J., & Lynch, A. (1991). Use of size-frequency data to estimate the age composition of crayfish populations (Vol. 48).
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.
Schlüsselwörter: Krebs, lÄngenfrequenz, methode, statistik, population
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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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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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Chen, Y., Jackson, D. A., & Harvey, H. H. (1992). A comparison of von Bertalanffy and polynomial functions in modelling fish growth data (Vol. 49).
Zusammenfassung: We compared the von Bertalanffy growth function (VBGF) and five polynormial functions (PF) in modelling fish growth for 16 populations comprising six species of freshwater fishes. Ranked results of the variance explained by each growth function indicated that VBGF described growth data better than three- and four-parameter polynomial functions. Log-transforming length and age greatly improved the goodness-of-fit of the three-parameter polynomial function. Statistical comparison of growth between populations or sexes was done using a general linear model for polynomial functions. The VBGF proved to be the best growth model for all 16 populations.
Schlüsselwörter: Fischerei, wachstum, methode, theorie, modell, statistik
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Eckmann, R., Gaedke, U., & Wetzlar, H. J. (1988). Effects of Climatic and Density-Dependent Factors on Year-Class Strength of Coregonus lavaretus in Lake Constance (Vol. 45).
Zusammenfassung: The influences of density-dependent and density-independent factors on year-class strength (YCS) of Corogonus lavaretus in Lake Constance were studied by multiple linear regression analyses for the period from 1962 to 1982. Meteorological conditions that lead to early thermal stratification of the lake in April are of prime importance for YCS and account for 41% of the total YCS variance. Zooplankton concentration during spring has no significant influence on YCS. The extensive stocking program on the lake (50-200 million larvae stocked per year) significantly supports YCS, but this relationship becomes apparent only after the influence of meteorological conditions are removed from the data.
Schlüsselwörter: Fischerei, zeitreihe, modell, statistik
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