Understanding for better protection: an innovative joint FNRS-FRQ research project on the St. Lawrence beluga whale

The beluga whale (Delphinapterus leucas) of the St. Lawrence Estuary (SLE) in Quebec, Canada, lives in a marine ecosystem heavily impacted by human activities and has shown no signs of recovery for several decades. Also known as the white whale or white dolphin, the beluga has a life expectancy of around 70 years. Infectious diseases and an increase in post-partum mortality in females have been observed, but the exact causes remain undetermined. However, exposure to contaminants is thought to be one of the causes of the increase in early mortality observed in recent years.

One of the main limitations to assessing the health of individuals in this population in relation to contaminant exposure is the lack of a method for determining the age of live beluga whales in the ESL.

Until now, the most reliable method for determining their age was to count the growth streaks on the inside of their teeth. The expertise of Namur-based researchers at Professor Frédéric Silvestre's Laboratoire de Physiologie Évolutive et Adaptative (LEAP) will enable the development of a new "epigenetic clock" and its use to estimate the age of living belugas, ultimately improving conservation strategies to help this threatened population recover.

The project is entitled: "Une horloge épigénétique pour estimer l'âge des belugas du Saint-Laurent et son impact sur l'accumulation de contaminants, le stress et la santé de cette population menacée"

Epigenetics is the study of changes in gene activity, not involving modification of the DNA sequence, that can be transmitted during cell divisions. One of the elements that "regulate" gene expression is methylation: a chemical group that attaches itself to certain places on the DNA strand to promote or limit gene expression. In recent decades, it has been discovered that methylation changes in a predictable way during aging, according to a pattern known as the "epigenetic clock". Once this clock has been established for a given population of individuals, it is therefore possible to deduce an individual's age by looking for the presence or absence of methylation on DNA. All it takes is a few cells, such as skin cells.

A team of top scientists from both regions is involved.

• Pr Frédéric Silvestre and Dr Alice Dennis - UNamur, Belgium
• Dr Krishna Das - ULiège, Belgium
• Dr Jonathan Verreault - Université du Québec à Montréal, Canada
• Dr Stéphane Lair - Université de Montréal, Canada
• Dr Magali Houde - Environment and Climate Change Canada
• Dr Véronique Lesage - Fisheries and Oceans Canada
• Dr Robert Michaud - Group for Research and Education on Marine Mammals (GREMM), Quebec, Canada

The research team will validate this new method and investigate the link with contaminant accumulation, physiological stress and overall health in this threatened population, comparing the ESL population with a healthier population of belugas from the Canadian Arctic.

In summary, this research aims to better understand how biological age, as measured by the epigenetic clock, influences the vulnerability of belugas to environmental stressors and their health.

This project will address fundamental research questions never before explored in beluga whales,

A new PhD student will join the Namur team, under the supervision of Frédéric Silvestre and will work in collaboration with researcher Justine Bélik on the basis of the EpiClock she developed for the mangrove rivulus.

Along with a project on mangrove rivulus in Florida and Belize, and one on fish and invertebrate populations in the Ecuadorian mountains, this is the third scientific project to use Namur researchers' expertise in ecological epigenetics in wild animals to help preserve biodiversity.

Collaborative research F.R.S.-FNRS - FRQ (Fédération Wallonie-Bruxelles - Québec)

The F.R.S.-FNRS has launched PINT-Bilat-P calls for bilateral research projects with the Fonds de Recherche du Québec. These calls are part of a drive to develop strategic partnerships. The aim of this bilateral research program is to create a leverage effect for scientific excellence and to encourage researchers from the Wallonia-Brussels Federation and Quebec to develop innovative joint research projects.

• Long-term effects of pollution in our rivers, oceans and lakes
• Understanding epigenetics to conserve biodiversity