@article{fdi:010049652,
  title = {{A} pioneer validation of a state-space model of vessel trajectories ({VMS}) with observers' data},
  author = {{W}alker, {E}mily and {B}ez, {N}icolas},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the context of the expansion of animal tracking and bio-logging, state-space models have been developed with the objective to characterise animals' trajectories and to understand the factors controlling their behaviour. {I}n the fisheries community, the electronic tagging of vessels commonly designated by {V}essel {M}onitoring {S}ystems ({VMS}) is developing and provides a new insight for the understanding, the analysis and the modelling of the trajectories of vessels and their prospecting behaviour. {VMS} data are thus a clue for the proper definition of fishing effort which remains a fundamental parameter of tuna stock assessments. {I}n this context, we used the {VMS} (recording of hourly positions) of the {F}rench tropical tuna purse-seiners operating in the {I}ndian {O}cean to characterise three types of movement (states) on the {VMS} trajectories (stillness, tracking, and cruising). {B}ased on empirical evidences, and on the regular frequency of {VMS} acquisition, this was achieved by the development of a {B}ayesian {H}idden {M}arkov model for the speeds and turning angles derived from the hourly steps of the trajectories. {I}n a second phase, states were related to activities disentangling stillness into fishing or stop at sea. {F}inally the quality of the model performances was rigorously quantified thanks to observers' data. {C}onfronting model prediction and true activities allowed estimating that 10% of the hourly steps were misclassified. {T}he assumptions and model' choices are discussed, highlighting the fact that {VMS} data and observers' data having different time resolutions, the effective use of validating data was troublesome. {H}owever, without validation, these analyses remain speculative. {T}he validation part of this work represents an important step for the operational use of state-space models in ecology in the broad sense (predators' tracking data, e.g. birds or mammals trajectories).},
  keywords = {{S}tate-space model ; {T}rajectory ; {V}essel {M}onitoring {S}ystems ({VMS}) ; {M}arkov ; {B}ayes ; {V}alidation ; {T}ropical tuna purse-seiners ; {O}bservers' data},
  booktitle = {},
  journal = {{E}cological {M}odelling},
  volume = {221},
  numero = {17},
  pages = {2008--2017},
  ISSN = {0304-3800},
  year = {2010},
  DOI = {10.1016/j.ecolmodel.2010.05.007},
  URL = {https://www.documentation.ird.fr/hor/fdi:010049652},
}