Publications des scientifiques de l'IRD

Joo R., Bertrand Sophie, Chaigneau Alexis, Niquen M. (2011). Optimization of an artificial neural network for identifying fishing set positions from VMS data : an example from the Peruvian anchovy purse seine fishery. Ecological Modelling, 222 (4), p. 1048-1059. ISSN 0304-3800.

Titre du document
Optimization of an artificial neural network for identifying fishing set positions from VMS data : an example from the Peruvian anchovy purse seine fishery
Année de publication
2011
Type de document
Article référencé dans le Web of Science WOS:000287291000014
Auteurs
Joo R., Bertrand Sophie, Chaigneau Alexis, Niquen M.
Source
Ecological Modelling, 2011, 222 (4), p. 1048-1059 ISSN 0304-3800
The spatial behavior of numerous fishing fleets is nowadays well documented thanks to satellite Vessel Monitoring Systems (VMS). Vessel positions are recorded on a frequent and regular basis which opens promising perspectives for improving fishing effort estimation and management. However, no specific information is provided on whether the vessel is fishing or not. To answer that question, existing works on VMS data usually apply simple criteria (e.g. threshold on speed). Those simple criteria generally focus in detecting true positives (a true fishing set detected as a fishing set); conversely, estimation errors are given no attention. For our case study, the Peruvian anchovy fishery, those criteria overestimate the total number of fishing sets by 182%. To overcome this problem an artificial neural network (ANN) approach is presented here. In order to set both the optimal parameterization and use "rules" for this ANN, we perform an extensive sensitivity analysis on the optimization of (1) the internal structure and training algorithm of the ANN and (2) the "rules" used for choosing both the relative size and the composition of the databases (DBs) used for training and inferring with the ANN. The "optimized" ANN greatly improves the estimates of the number and location of fishing events. For our case study, ANN reduces the total estimation error on the number of fishing sets to 1% (in average) and obtains 76% of true positives. This spatially explicit information on effort, provided with error estimation, should greatly reduce misleading interpretations of catch per unit effort and thus significantly improve the adaptive management of fisheries. While fitted on Peruvian anchovy fishery data, this type of neural network approach has wider potential and could be implemented in any fishery relying on both VMS and at-sea observer data. In order to increase the accuracy of the ANN results, we also suggest some criteria for improving sampling design by at-sea observers and VMS data.
Plan de classement
Ressources halieutiques [040] ; Télédétection [126]
Localisation
Fonds IRD [F B010053066]
Identifiant IRD
fdi:010053066
Contact