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Is speed through water a better proxy for fishing activities than speed over ground? ArchiMer
Gloaguen, Pierre; Woillez, Mathieu; Mahevas, Stephanie; Vermard, Youen; Rivot, Etienne.
Understanding fishing vessel dynamics at a fine spatial scale is of great interest for defining appropriate spatial management plans. Different models have been developed to detect fishing activity from Vessel Monitoring System (VMS) data. While mathematical and statistical methods differ, all rely on the idea that vessel speed over ground provides information on fishing vessel activity. However, trawling with constant speed relative to the water mass may as well prove a winning strategy for both technical (to ensure sufficient trawl opening) and biological (to limit escapement of fish) reasons. Therefore, considering speed through water instead of speed over ground might provide insights into fishing activities. We developed a method combining surface...
Tipo: Text Palavras-chave: Vessel monitoring system surface currents hidden Markov models; MARS 3D; Obsmer.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00359/47030/46948.pdf
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An autoregressive model to describe fishing vessel movement and activity ArchiMer
Gloaguen, Pierre; Mahevas, Stephanie; Rivot, Etienne; Woillez, Mathieu; Guitton, Jerome; Vermard, Youen; Etienne, Marie-pierre.
The understanding of the dynamics of fishing vessels is of great interest to characterize the spatial distribution of the fishing effort and to define sustainable fishing strategies. It is also a prerequisite for anticipating changes in fishermen's activity in reaction to management rules, economic context, or evolution of exploited resources. Analyzing the trajectories of individual vessels offers promising perspectives to describe the activity during fishing trips. A hidden Markov model with two behavioral states (steaming and fishing) is developed to infer the sequence of non-observed fishing vessel behavior along the vessel trajectory based on Global Positioning System (GPS) records. Conditionally to the behavior, vessel velocity is modeled with an...
Tipo: Text Palavras-chave: Hidden Markov model; Vessels dynamics; RECOPESCA; Autoregressive process; Baum-Welch algorithm.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00179/29049/27485.pdf
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Modélisation mécaniste et stochastique des trajectoires pour l'halieutique ArchiMer
Gloaguen, Pierre.
Driven by ecological questions about determinism of individuals, movement ecology has known large developments in recent years. This enthusiasm was largely possible thanks to the emergence of GPS technologies for the last 20 years, and, therefore, the establishment of numerous databases of individual trajectories. These observations at fine spatial and temporal scales of individuals give the opportunity to identify specific behaviors of individuals and their perception of the environment in which they operate. To process this data, and identify the mechanisms of interest to ecologists, many recent movement models describing the movement mecanisms have been developed. In fisheries Science, with the development of GPS systems, the study of movement and...
Tipo: Text
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00310/42092/41391.pdf
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Mechanisms of change in human behaviour ArchiMer
Marchal, Paul; Bartelings, Heleen; Bastardie, François; Batsleer, Jurgen; Delaney, Alyne; Girardin, Raphael; Gloaguen, Pierre; Hamon, Katell; Hoefnagel, Ellen; Jouanneau, Charlène; Mahevas, Stephanie; Nielsen, Rasmus; Piwowarczyk, Joanna; Poos, Jan-jaap; Schulze, Torsten; Rivot, Etienne; Simons, Sarah; Tidd, Alex; Vermard, Youen; Woillez, Mathieu.
The scope of this report is to present the science developed within the VECTORS project to improve the understanding of the key processes driving the behaviour of human agents utilising a variety of EU maritime domains. While particular attention has been paid to the spatial interactions between fishing activities and other human uses (e.g., maritime traffic, offshore wind parks, aggregate extractions), the behaviour of non-fishing sectors of activity has also been considered. Various quantitative and semi-qualitative approaches have been pursued to gain better insight into behavioural drivers based on past data, and also forecast how human agents would react if access was constrained by either management (e.g. Marine Protected Areas – MPA), or the...
Tipo: Text
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00223/33377/31802.pdf
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Stochastic differential equation based on a multimodal potential to model movement data in ecology ArchiMer
Gloaguen, Pierre; Etienne, Marie-pierre; Le Corff, Sylvain.
The paper proposes a new model for individuals' movement in ecology. The movement process is defined as a solution to a stochastic differential equation whose drift is the gradient of a multimodal potential surface. This offers a new flexible approach among the popular potential-based movement models in ecology. To perform parameter inference, the widely used Euler method is compared with two other pseudolikelihood procedures and with a Monte Carlo expectation-maximization approach based on exact simulation of diffusions. Performances of all methods are assessed with simulated data and with a data set of fishing vessel trajectories. We show that the usual Euler method performs worse than the other procedures for all sampling schemes.
Tipo: Text Palavras-chave: Exact simulation; Global Positioning System data; Local linearization; Movement model; Pseudolikelihood methods; Stochastic differential equation.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00429/54068/55461.pdf
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Modelling Fishing Vessels Movement and Activity ArchiMer
Gloaguen, Pierre; Mahevas, Stephanie; Rivot, Etienne; Woillez, Mathieu; Guitton, Jérome; Vermard, Youen; Etienne, Marie-pierre.
Tipo: Text
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00371/48181/48296.pdf
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