Validation et exploitation de nouvelles techniques d’imagerie numérique pour la caractérisation des profils comportementaux chez les poissons. Etude de l’influence de facteurs abiotiques et biotiques chez Symphodus ocellatus (Forsskål, 1775) et Chromis chromis Linné, 1758, Labridé et Pomacentridé méditerranéens

In many fields dedicated to behavioural research, digital imaging techniques
(D.I.T.) now allow the conceptualisation of tools and systems from which the descriptive
precision, the capabilities to detect, to analyse and to quantify behavioural parameters
open original and very promising prospects. By the computing power offered by these
new techniques, behavioural scientists have the possibility to quantify a large number of
variables, which generally cannot be measured by usual methods of direct observation.
The research works presented in this thesis, using new ethometric techniques
based on D.I.T., concerned several questions relating to the study of effects of
environmental factors on behavioural patterns in fish. By this way, we adjusted,
experienced and operated complementary D.I.T. through field and lab researches.
After a extensive general introduction devoted to D.I.T. developments and to its
contributions in the study of animal behaviour, we present our works in two major parts.
These two parts concern:
1.- Field studies conducted with the use of Digital Elevation Modelling (DEM)
techniques and using classical methods of SCUBA diving direct observation of
fish behaviour;
2.- Lab works using classical methods of direct observation and the techniques of
computerised vision systems via the ETHOVISION® Color-Pro computerised
video tracking system.
The first part exposes research devoted to:
Chapter 1 – the Use of DEM of natural aquatic habitats to characterised space and time
utilisation modes during reproduction in the Mediterranean wrasse Symphodus ocellatus
(Forsskål, 1775).
The second part exposes research devoted to:
Chapter 2 – the Study of effects of water temperatures and photoperiod (abiotic
variables) on the display of reproductive behavioural patterns in the ocellated wrasse
(Symphodus ocellatus) acclimated in large tank (5 M³ mesocosm) replicating a
Mediterranean biotope;
Chapter 3 – the Adjustment and the validation of the ETHOVISION® Color-Pro
computerised video tracking system to the characterisation of behavioural patterns in
aquarium swimming freely fishes. Study of effects of water temperature (abiotic
variable) and congeners density (biotic variable) on spontaneous swimming behaviour in
the Mediterranean damselfish Chromis chromis Linné, 1758.
A general discussion mainly centred on new potential applications of digital
imaging techniques to the fields of behavioural and environmental sciences, concludes
this PhD dissertation.