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Trenkel, Verena. |
In my work, which is summarised in this paper for obtaining accreditation to supervise research (the HDR), I addressed three areas: i) statistical methods of estimating the density of living resources, ii) mathematical models of population dynamics for estimating the abundance of marine populations and iii) methods for detecting temporal changes in the status of exploited populations. My work has focused on: i) Many studies of the observability of fish by trawling and by video and the development of stochastic models to better assess local fish densities. ii) Development of models without commercial catches, using Bayesian and frequentist approaches; the study of multi-specific relationships and the proposal for a threshold predator-prey model. iii)... |
Tipo: Text |
Palavras-chave: Statistics; Abundance estimation; Stock assessment; Statistiques; Estimation d'abondance; Evaluation des stocks. |
Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/rapport-1545.pdf |
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Roos, David; Pelletier, Dominique; Ciccione, Stéphane; Taquet, Marc; Hughes, George. |
Monitoring the abundance of green turtles (Chelonia mydas) is necessary to assess population trends and risks of collapse. This note presents a study aimed at comparing three techniques for the direct estimation of green turtle numbers in their foraging habitats (seagrass beds and reef flats). The experiment was carried out at Mayotte Island, Western Indian Ocean. The techniques involved were surveys by snorkel, and aerial surveys using a microlight aircraft and a paramotor. Each technique had shortcomings and advantages. While each technique provided estimations of turtle numbers only surveys by snorkel permitted identification of species and sex, whenever visibility and turtle behaviour permitted. Along the shorelines, and over foraging areas, the... |
Tipo: Text |
Palavras-chave: Foraging habitats; Snorkelling survey; Aerial survey; Abundance estimation; Chelonia mydas; Green turtle. |
Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-432.pdf |
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