Les chalutages experimentaux: Utilisation de la temperature et de la profondeur comme variables auxiliaires.
Very often stratification of bottom-trawl surveys is done by using a stratified random sampling scheme. If a survey is directed towards a group of species, the sampling scheme has to be a compromise between these different interests. So the sampling scheme is not totally efficient for each of the sp...
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| Format: | Article in Journal/Newspaper |
| Language: | French |
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ISTPM
1984
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| Online Access: | https://archimer.ifremer.fr/doc/1984/publication-1803.pdf https://archimer.ifremer.fr/doc/00000/1803/ |
| Summary: | Very often stratification of bottom-trawl surveys is done by using a stratified random sampling scheme. If a survey is directed towards a group of species, the sampling scheme has to be a compromise between these different interests. So the sampling scheme is not totally efficient for each of the species. The use of auxiliary variables, as depth or temperature, looks as if such supplementary informations could neither improve the efficiency of the estimators nor the subsequent analysis (analysis of covariance). Dans le but d'optimiser la précision des estimations d'indices d'abondance provenant des campagnes de chalutages expérimentaux on utilise très couramment une stratégie d'échantillonnage stratifié. Lorsque ces campagnes visent plusieurs espèces la stratification est le plus souvent le résultat d'un compromis, et donc n'est optimale pour aucune des espèces cibles. L'utilisation de variables auxiliaires, telles la profondeur ou la température, ne semble pas pouvoir déboucher sur une amélioration des estimateurs ou des analyses subséquentes (analyse de covariance). |
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