Brunke, M., Schwörbel, J., & Wendling, K. (1995). Die Auswirkungen eines Flußtunnels auf die Fliessgewässerbiozoenose: Makrozoobenthon und Fischfauna (Vol. 24).
Zusammenfassung: Im Stadtgebiet von Idar-Oberstein wurde die Nahe auf einer Laenge von 1880 m durch Ueberbauung und massiven Ausbau der Sohle hermetisch vom Umland abgeschlossen. Zusaetzlich wurde der natuerliche Geschiebebetrieb durch ein Wehr oberhalb des Tunnels unterbrochen. Die Makroinvertebraten- und Fischfauna ist im Tunnel hinsichtlich der Artenzusammensetzung und der Individuendichte verarmt, eine photoautotrophe Besiedlung fehlt. Die Driftdichte ist im Tunnel verringert, die Driftrate erhoeht, der Sauerstofftagesgang stark veraendert. Einfluesse auf die nahen Bereiche ober- und unterhalb des Tunnels liessen sich in dieser Untersuchung nicht feststellen. Hinweise auf oekologische Aspekte bei der Konstruktion aehnlicher Anlagen werden gegeben.
Schlüsselwörter: Wasserbau, Ökologie, Gewässerverbau, Fisch
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Wang, Y. G., & Thomas, M. R. (1995). Accounting for individual variability in the von Bertalanffy growth model (Vol. 52).
Zusammenfassung: Estimation of von Bertalanffy growth parameters has received considerable attention in fisheries research. Since Sainsbury much of this research effort has centered on accounting for individual variability in the growth parameters. In this paper we demonstrate that, in analysis of tagging data, Sainsbury's method and its derivatives do not, in general, satisfactorily account for individual variability in growth, leading to inconsistent parameter estimates (the bias does not tend to zero as sample size increases to infinity). The bias arises because these methods do not use appropriate conditional expectations as a basis for estimation.
Schlüsselwörter: Fisch, Statistik, Methode, Vergleich, Wachstum, Bertalanffy, Faben
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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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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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Leshkevich, G. A. (1995). Great Lakes CoastWatch program update.
Zusammenfassung: As the CoastWatch regional node for the Great Lakes, the Great Lakes Environmental Research Laboratory (GLERL) is working to obtain and/or develop and deliver environmental data and products for near real-time monitoring of the Great Lakes to support environmental science and decision making. In support of this goal, GLERL is providing access to near real-time and retrospective satellite observations and in-situ data for the Great Lakes to Federal, state, and local agencies and academic institutions. There are currently nearly 40 regional CoastWatch users. The goals and objectives of the Great Lakes CoastWatch Program directly support agency statutory responsibilities in estuarine and marine science, living marine resource protection, and ecosystem monitoring and management. GLERL is currently receiving an enhanced digital image product suite of 26 images including satellite derived surface-temperature, visible and near-infrared reflectance, brightness temperatures, satellite and solar zenith angle data, and cloud masks from the NOAA-12 satellite. These products are downloaded from the NOAA Ocean Products Center (OPC) via INTERNET on a daily basis and archived at GLERL. Over 32,000 image products have been received and archived since becoming the Great Lakes CoastWatch Node in 1990. GOES-8 data is also currently being received.
Schlüsselwörter: North-America,-Great-Lakes; monitoring-; decision-making; satellite-technology; coastal-waters; ecosystems-; data-transmission; environmental-monitoring; satellite-sensing
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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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Hoenig, J. M., Morgan, M. J., & Brown, C. A. (1995). Analysing differences between two age determination methods by tests of symmetry (Vol. 52).
Zusammenfassung: A common problem in fisheries science is the comparison of two methods for obtaining ages of individual animals. The authors suggest that if the overall level of agreement is low between two ageing methods used on the same sample of fish, then one can use a test of symmetry to look for evidence of systematic disagreement. A chi super(2) test is used to determine if the number of fish assigned age i from method 1 and age j from method 2 differs significantly from the number of fish assigned age j from method 1 and age i from method 2. Such a test can also be used to determine the range of nominal ages over which two methods appear to give comparable results.
Schlüsselwörter: Altersbestimmung, Fischerei, Statistik, Methode
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(1995). Fischfauna der Bundeswasserstraßen in Berlin, Brandenburg, Sachsen-Anhalt. Koblenz: Bundesanstalt fuer Gewaesserkunde, Koblenz (Selbstverlag).
Schlüsselwörter: Arteninventar, Bestandsaufnahme, Kartierung, Fisch
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Baars, M. (1995). Fischereibiologische Untersuchung zur Problematik von Ausleitungskraftwerken an der Glonn (Landkreis Dachau, Obb.). München: Technische Universität.
Schlüsselwörter: Fisch, Kraftwerk
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Baer, O. (1995). Die Flußperlmuschel (Margaritifera margaritifera L.) (0thVol. 619). Die Neue Brehm-Büscherei. Magdeburg und Heidelberg.
Schlüsselwörter: Muschel, Margaritifera
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