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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Müller, R., Bia, M. M., & Meng, H. J. (1995). Die Felchenfischerei in einigen Seen der Zentralschweiz und des Mittellandes (Vol. 55).
Schlüsselwörter: Fisch, Schweiz, Felchen, Coregonus, Vorkommen, Maräne
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Müller, W. (1995). Die Sache mit dem Kormoran: Dauerbrenner im Artenschutz.
Schlüsselwörter: Fisch, Kormoran, Phalacrocorax carbo, Schaden, Fischerei
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Müller, W. (1995). Kormoran: auf Seen willkommen, an Flüssen weniger: Einigung zwischen Vogelschutz und Fischerei.
Schlüsselwörter: Fisch, Kormoran, Phalacrocorax carbo, Schaden, Fischerei
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Nagel, L. (1995). Biomanipulation in der Binnenfischerei (Vol. 1995).
Schlüsselwörter: Fisch, Fischerei, Biomanipulation
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Pekny, R. (1995). Über die Gefährdung autochthoner Krebsbestände, insbesondere durch ausländische Krebsarten (Vol. 1995).
Schlüsselwörter: Krebse, Gefährdung
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Peter, A. J. (1995). Lebensraumänderungen in Fließgewässern – eine fischbiologische Perspektive (Vol. 4).
Schlüsselwörter: Fisch, Wasserbau, Kraftwerk, Diversität, Biologie
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Petrick, G. (1995). Zur Fischfauna des Gülper Sees und der Unteren Havelniederung (Vol. 4).
Zusammenfassung: Die Fischfauna der als Feuchtgebiet internationaler Bedeutung ausgewiesenen Flussaue ist durch Verschlammung und Eutrophierung gefaehrdet. Insbesondere die im Kies laichenden Arten Rapfen und Zope verlieren Lebensraum. Blei und Guester sind die einzigen Arten mit positiver Bestandstendenz. Charakteristische Arten wie Schleie, Karausche und Hecht nehmen ab. Das Flussneunauge ist ausgestorben. Hilfsmassnahmen sind erforderlich, nach weiteren vorbereitenden Untersuchungen muessen sie zusammen mit Fischern umgesetzt werden.
Schlüsselwörter: Fisch, Vorkommen, Arteninventar, Kartierung
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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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