A comparison of statistical models for short categorical or ordinal time series with applications in ecology

We study two statistical models for short-length categorical (or ordinal) time series. The first one is a regression model based on generalized linear model. The second one is a parametrized Markovian model, particularizing the discrete autoregressive model to the case of categorical data. These models are used to analyze two data-sets: annual larch cone production and weekly planktonic abundance.Comment: 18 page

Est-ce que le moment de la journée peut influencer les effets d'un programme d'activités physiques sur le contrôle postural de personnes âgées institutionnalisées ?

International audienc

Influence de la sensibilité cutanée plantaire sur les variations quotidiennes du contrôle postural et de la marche chez les personnes âgées institutionnalisées : analyse en cluster

International audienc

Influence de la chronobiologie sur les activités posturo-cinétiques chez les sujets atteints de la maladie d’Alzheimer

COMInternational audienc

Daily and seasonal estimates of the recruitment and biomass of glass eels runs (

The European eel (Anguilla anguilla) is drastically declining in all its distribution area and listed in the red list of the IUCN (International Union for Conservation of Nature). A rebuilding plan was adopted at European level in 2007, Regulation R(CE) 100/2007, to restore eel abundance to the level observed during the seventies. Its implementation started on the 1st of January 2009. This species is heavily threatened by numerous activities including fishing, and its management can only be effective through a systemic approach minimizing the whole range of human-induced impacts on the resource and its habitat. In the framework of the European interregional programme INTERREG IIIB-Atlantic Area– the INDICANG project aimed at elaborating abundance indicators of the European eel in the central part of its distribution area (http://www.ifremer/fr/indicang/). A methodological guide was elaborated by this project to define the indicators needed for this resource assessment. In this framework, Ifremer (Institut Français pour l'Exploitation de la Mer) and the UPPA University (Université de Pau et des Pays de l'Adour) have developed a method to estimate the daily and seasonal biomass of glass eels with the view to evaluate the fishery's impact on the estuarine eel recruitment to the Adour catchment. The estimation method uses observations from nightly scientific surveys to estimate glass eels' densities in the water column during various flood tides characterized by different hydrodynamic conditions. Information on these conditions allows the estimation of the glass eels biomass migrating during the night. From these estimates and reported catches made by the fishery during the same night, the exploitation rate applied by the fishery on the flow of glass eels progressing upstream during night flood tides is estimated. The relationship between the exploitation rate, fishery catches and hydrodynamic conditions allowed the estimation of the exploitation rate and nocturnal biomass fluctuations during the fishing season, from November 1st to March 31st of the following year. Finally, from the chronological series of biomass migrating at night, the total biomass migrating every day and the total recruitment into the estuary, during the main glass eel migration period, are estimated. Estimations made between 1998 and 2005 indicate that the overall rate of exploitation of the marine and continental fisheries, on average, is of 15.7%, ranging between 8 and 25% according to fishing seasons

Concentrations en éléments traces dans des pelotes de réjection et des excréments d’un oiseau de rivière spécialiste (cincle plongeur): une approche indirecte pour l’évaluation environnementale?

AFFInternational audienc

Estimating daily passive fish abundance in an open estuary from sparse data in spatio-temporal sampling: particular case of glass eel flows

28 pagesA methodology to estimate glass eel (Anguilla anguilla L.) abundance on a daily basis containing sparse data is proposed. Our analyses are based on scientific in situ campaigns data coming from a sampling protocol which leads to spatio-temporal blanks in the fish distribution along the estuary and the time period that must be taken into account in fish abundance estimate calculated using the sparse data. Estimates at each catch locations are calculated and then extended to the whole section of the river from a Bayesian extrapolation approach which leads to a spatially explicit method. The method proposed a resulting estimator assessing a non-linear model of current speed (a crucial element for the behaviour of this passive fish) and the sampling design jointly being able to estimate the abundance of glass eel migrating during a given day in the presence of sparse data. Confidence intervals are also proposed calculated using the sensitivity of the biomass estimates to the statistical methodology and the choice of spatial extrapolation

Daily and seasonal biomasses estimates of the recruitment and biomass of glass eels runs (Anguilla anguilla) and exploitation rates in an opened estuary in an opened estuary (Southwestern France)

ACLInternational audienceno abstrac

Update of striped red mullet abundance indices from professional fishing data (2016-2018)

The ROMELIGO project included a proposal of abundance indicators for mur-west stock using professional fishing data. The methodolgy is based on the selection of samples of representative vessels grouped in clusters with the same technical characteristics, taking into account their LPUE for specifed period and area. The analysis was conducted on an historical dataset from 2005 to 2015. To be able to update it, conditional decision trees were used to find rules to assign any new vessels to one of the predefined OTB or GNS clusters. Then, the trends of LPUE on the overall period were considered. For OTB, the number of uses shows little variation during the period. In recent years, the LPUEs calculated for the Bay of Biscay show low levels compared to the whole series. The end of the series seems to be marked by an upward recovery which will remain to be confirmed in the following years. For GNS and over the whole period, a downward trend is observed in three out of four cases for the number of fishing sequences and in two out of four cases for the average LPUE. Professionals identified one management measure likely to affect the OTB indicators. After analysis, it is estimated that it did not impact the trends of the series. No regulatory element was identified for GNS. Currently five fleets are selected for the Bay of Biscay (one for OTB and four for GNS). For the GNS indicators, the number of uses decreases in three out of four cases, that concerning the mesh class 50 - 59 mm in the 2nd quarter reaching a very low level (around 40 sequences in 2018). It is proposed to no longer use this last indicator because we consider that it is no longer representative. For the others, more in-depth work should be able to be carried out in the project ACOST. At the same time, the interest of considering the Danish seine gear could be posed because the length of the series is now sufficient