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| Taormina, Bastien; Marzloff, Martin; Desroy, Nicolas; Caisey, Xavier; Dugornay, Olivier; Metral Thiesse, Emmanuelle; Tancray, Aurelien; Carlier, Antoine. |
| Underwater imagery is increasingly used as an effective and repeatable method to monitor benthic ecosystems. Nevertheless, extracting ecologically relevant information from a large amount of raw images remains a time-consuming and somewhat laborious challenge. Thus, underwater imagery processing needs to strike a compromise between time-efficient image annotation and accuracy in quantifying benthic community composition. Designing and implementing robust image sampling and image annotation protocols are therefore critical to rationally address these trade-offs between ecological accuracy and processing time. The aim of this study was to develop and to optimize a reliable image scoring strategy based on the point count method using imagery data acquired on... |
| Tipo: Text |
Palavras-chave: Benthic monitoring; Fouling community; Sampling design; Taxonomic resolution; Underwater imagery. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71160/69550.pdf |
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| Beliaeff, Benoit; Burgeot, Thierry. |
| Activity of 7-ethoxyresorufin-O-deethylase (EROD) in fish is certainly the best-studied biomarker of exposure applied in the field to evaluate biological effects of contamination in the marine environment. Since 1991, a feasibility study for a monitoring network using this biomarker of exposure has been conducted along French coasts. Using data obtained during several cruises, this study aims to determine the number of fish required to detect a given difference between 2 mean EROD activities, i.e. to achieve an a priori fixed statistical power (l-beta) given significance level (alpha), variance estimations and projected ratio of unequal sample sizes (k). Mean EROD activity and standard error were estimated at each of 82 sampling stations. The... |
| Tipo: Text |
Palavras-chave: Biomonitoring; Estimation; EROD activity; Statistical power; Sample size; Sampling design. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00337/44787/44483.pdf |
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| Vigneau, Joel; Mahevas, Stephanie. |
| Measuring fish on a market or on board a vessel is the most common action taken by biologists all around the world to gather data for stock assessment. The samples coming from this kind of survey are of vector type and are not straightforward to analyse and compare. This paper proposes a generic tool that enables to investigate in any multinomial like sampling scheme. The use of this tool will be discussed based on examples from two different sampling designs. One is a sampling of commercial market categories and the other is a métier based sampling. The research of outliers, misallocated samples or potential bias, the stratification and the analysis of within and between strata variance will be discussed with the objective of constructing the best... |
| Tipo: Text |
Palavras-chave: Stratification; Sampling design; Length structure; Market sampling. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-2698.pdf |
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| Vigneau, Joel; Mahevas, Stephanie. |
| Measuring fish on board fishing vessels or at fish markets to collect data for stock assessment purposes is one of the most straightforward actions carried out by fisheries scientists worldwide. However, such samples are not straightforward to handle and analyse because of their vector-type structure. A generic tool that allows investigation in any multinomial-like sampling scheme is provided, as long as the scheme is built on a ratio estimator, which is the case for most length sampling in the fisheries sector. The use of this tool is discussed using data obtained from two different sampling designs, one consisting of commercial market samples by category and the other on fishing activity or metier. The identification of outliers, misallocated samples, or... |
| Tipo: Text |
Palavras-chave: Stratification; Sampling design; Market sampling; Length structure. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2731.pdf |
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| McRoberts, Ronald Edward; Tomppo, Erkki Olavi; Vibrans, Alexander Christian; Freitas, Joberto Veloso de. |
| Forests contribute substantially to maintaining the global greenhouse gas balance, primarily because among the five economic sectors identified by the United Nations Framework Convention on Climate Change, only the forestry sector has the potential to remove greenhouse gas emissions from the atmosphere. In this context, development of national forest carbon accounting systems, particularly in countries with tropical forests, has emerged as an international priority. Because these systems are often developed as components of or in parallel with national forest inventories, a brief review of statistical issues related to the development of forest ground sampling designs is provided. This overview addresses not only the primary issues of plot configurations... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sampling design; Plot configuration; Remote sensing; Uncertainty Desenho amostral; Formato de parcelas; Sensoriamento remoto; Incerteza; Estudos de caso. |
| Ano: 2013 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/430 |
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