Master 2 Internship
Research topic
Impact of anthropogenic stressors on the metamorphosis of the common two-banded sea bream Diplodus vulgaris
Laboratory
UMR 7232 CNRS-SU, Biologie Intégrative des Organismes Marins (BIOM), EcoEvoDevo Team
Address
Observatoire Océanologie de Banyuls-sur-Mer, 1 avenue Pierre Fabre, Banyuls-sur-Mer, France
Dates
January to July 2027
Stipend
Yes: ~ 600€ / month (French students)
Supervisor(s)
Summary
Most marine fishes have a bipartite life cycle, with a pelagic and dispersing larval phase followed by more sedentary juvenile and adult phases within coastal habitats. Research from our group showed that, in coral-reef fishes, the transition from the larval to the juvenile phase, called larval recruitment, coincides with a metamorphosis controlled by thyroid hormones (TH). Recent work from our team suggests that this is also the case for temperate reef fishes like the common two-banded sea bream Diplodus vulgaris.
Under the control of TH and metamorphic genes from the TH pathway, larval fishes undergo rapid and major morphological, physiological, and behavioural changes during metamorphosis. These changes are critical for fish survival in the juvenile populations within coastal habitats. Our previous research on coral-reef fishes showed that TH endocrine disruption induced by anthropogenic stressors such as increased temperatures and pollutants can lead to altered metamorphic changes, ultimately impairing juvenile fish survival and threatening the replenishment of fish populations. It is therefore possible to examine the ‘quality’ of larval and juvenile fish in nursery habitats by looking at their TH levels, levels of expression of metamorphic genes, and metamorphic traits such as size, shape, body condition, pigmentation patterns, and specific behaviours. By coupling these biomarkers with environmental parameters measured in nursery habitats (such as levels of certain pollution like heavy metals, pesticide, temperature, turbidity, and nutrient levels), it is thus possible to distinguish nurseries that are healthy habitats for metamorphosing fishes from nurseries that are ecological traps.
In this context, the intern will participate to the JUVAPORT project, which aims at investigating D. vulgaris physiological status in 4 contrasted zones of the Port-Vendres harbour characterized by various levels of metal pollution and occurrence of anthropogenic stressors, and examine how they correlate with potentially different metamorphic traits in recruiting D. vulgaris. In parallel, the intern will design laboratory experiments in which larval fish sampled from a non-contaminated area will be exposed to various levels of anthropogenic stressors (based on the results obtained in Port-Vendres). The intern will set up normalized bioassay to investigate the effects of these pollutants, as well as thermal stress (depending on time and efficiency) on a variety of metamorphic traits including TH levels, levels of expression of metamorphic genes, pigmentation patterns, behavioural performances. This internship is part of the FRAMES ANR project which examines the diversity and vulnerability of marine fish larval recruitment and metamorphosis strategies, and the JUVAPORT project.
The intern will (i) gain knowledge in fish ecophysiology, neuroendocrinology, behavioural ecology, fish sampling, and fish husbandry; (ii) develop bioinformatic, biomolecular, and laboratory techniques for measuring gene expressions and pigmentation changes; (iii) practice bioinformatic techniques for analysing and visualizing data; and (iv) acquire communication skills to present and share scientific results.
Related publications
- Roux N., Miura S., Dussene M., Tara Y., Lee S.-H., de Bernard S., Reynaud M., Salis P., Barua A., Boulathouf A., Balaguer P., Gauthier K., Lecchini D., Gibert Y., Besseau L., Laudet V. 2023. The multi-level regulation of clownfish metamorphosis by thyroid hormones. Cell Reports.
- Gairin, E., Dussenne, M., Mercader, M., Berthe, C., Reynaud, M., Metian, M., Mills, S.C., Lenfant, P., Besseau, L., Bertucci, F. Lecchini, D. 2022. Harbours as unique environmental sites of multiple anthropogenic stresses on fish hormonal systems. Molecular & Cellular Endocrinology.
- Besson M., Feeney W.E., Moniz I., François L., Brooker R.M., Holzer G., Metian M., Roux N., Laudet V., Lecchini D. 2020. Anthropogenic stressors impact fish sensory development and survival via thyroid disruption. Nature Communications.
- Holzer G., Besson M., Lambert A., François L., Barth P., Gillet B., Hughes S., Piganeau G., Leulier F., Viriot L., Lecchini D., Laudet V. 2017. Fish larval recruitment to reefs is a thyroid hormone-mediated metamorphosis sensitive to the pesticide chlorpyrifos. eLife.
How to apply?
Contact supervisor(s) with a CV, a Cover Letter, and references if relevant. Position opened until filled.
