The following image reflects my research interests as revealed by my publications titles and abstracts

Wordle JO

As you can see, I have been mostly interested in larvae, of fish, on coral reefs and how their orientation influences their dispersal and the connectivity of these ecosystems. Indeed, for coastal fishes, as for many other coastal organisms, the pelagic larval phase is often the main opportunity for dispersal. As such, it influences directly the connections between populations, hence forming meta-populations. MetapopAs recently as 15 years ago, fish larvae were mostly considered as plankton, i.e. passive particles moved around by currents. Dispersal was therefore supposed to cover vast distances and populations to be large, open, homogenous entities. There is now accumulating evidence for restricted dispersal, heterogeneity within small spatial scales, and, in parallel, strong behavioural abilities in larval fish. The current consensus is, therefore, that fish larvae are not passive and that their behaviour can be responsible for the restricted scale of dispersal.

I tackled these questions during with several different approaches: the development of a mathematical model of larval dispersal, the collection of data during a sampling campaign around an isolated atoll, and the experimental study, in situ, of the orientation of coral reef fish larvae with a novel device.

Now, I am also interested in the analysis of long-term time series collected in the Observatory of Villefranche which record both physico-chemical descriptors of the water masses and the abundance of plankton. One challenge of particular interest is the understanding and prediction of jellyfish outbreaks.


On a smaller scale, I am also helping with the statistical analysis within several different projects such as the automatic classification of seismic waves or the productivity of phytoplanktonic cultures in various conditions.


Laboratoire d'Océanographie de Villefranche

Station Zoologique, B.P. 28, Chemin du Lazaret, 06234 Villefranche-sur-Mer Cedex

irisson (at)
+33 (0)4 93 76 38 04

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