Recruitment and metamorphosis of reef fish post-larvae facing coastal anthropization in the Caribbean

Larval recruitment is an ecological process that corresponds to the return of post-larvae to the reef, after having undergone a pelagic phase. Once installed on the reef, they will undergo numerous physiological and morphological changes, corresponding to their metamorphosis, which is a primordial stage for their survival at this initial stage of their life.

The aim of this thesis project is to study the metamorphosis of post-larvae during recruitment, and more particularly in relation to their nutrition, on six study sites that are contrasted in terms of anthropogenic impacts.

During the first part of the thesis, a spatio-temporal study of the recruitment of post-larvae will be carried out in order to identify recruitment peaks during the year. We will also try to determine their larval life span (sclerochronology)

The second part of the thesis will focus on the study of the metamorphosis of post-larvae in relation to their nutrition through: morphology (jaw and digestive system), isotopic niches, microbiology (intestinal microbial communities) and the study of hormones (thyroid hormones and glucocorticoids).

Finally, the last part of the thesis will concern an in situ "transplantation" experiment allowing to follow the nutritional metamorphosis during radical changes in environmental conditions.

The expected results of this thesis, funded by the LabEx CORAIL, are to relate the influence of anthropogenic pressures on the life traits of young recruits, which are essential for the renewal of the stocks of adult populations.