Set-up of ⟪a quality assurance⟫ as part of sampling of an allis shad (Alosa alosa) population.

If the protocols of data acquisition are not formalized enough, in ecology or in population dynamics, we run the risk that, with time and different operators, there will be a non-measurable drift. The consequences may be serious when it comes to interpretations. To limit these risks, we have tried to standardize all stages of sampling data acquisition on functioning of the Alosa alosa population in the Gironde-Garonne-Dordogne drainage basin. After a detailed analysis of the acquisition stage, we have split it into 3 main parts the sampling procedure, the operative mode of sampling in the field and the operative mode of cleaning and mounting scales in the laboratory. Each part is shown chronologically; each task is explained and the exact path of information is specified throughout the transcriber chain (fish, scales, and data). Supplementary difficulties are essentially due to the time necessary to write the protocol in due form. On the other hand, at the moment of the carrying out the study, security and standardization save time for the data reliability.