Fish evolutionary biology

Hi! I’m Thomas,

I’m a broadly trained fish biologist interested in many aspects of fish life, from reproduction and development, anatomy and morphology, genetics, and evolution. I am most interested, however, in fish living or adapting to extreme or changing environmental conditions. I am currently a Research Associate in John Postlethwait laboratory at the University of Oregon. I obtained an Engineering degree in fisheries and aquaculture sciences and received my PhD in France on a fellowship co-funded by INRAE and IFREMER, which are the French equivalents of the USDA and NOAA, respectively.

Fish account for more than half of vertebrate species and are found in almost every aquatic environment on the planet, from the surface to hadal depths, from pole to pole, from marine to freshwater. But the true extent of fish diversity and the ways by which it evolved in such a dramatic array of body shapes, physiologies, and habitats, still remains poorly understood. Aquatic ecosystems today face extreme risks. Global warming and human activities are altering them at a magnitude never seen before. Many abiotic factors, such as temperature and pollution, as well as biotic factors, such as viruses and parasites, represent major threats to living organisms, including fish. These perturbations can tip a species or an ecosystem from a healthy state to collapse. We, however, have a limited understanding of fish sensitivity and resilience to ecological disturbance. We are therefore unable to predict how global warming and human activities will affect fish and how to mitigate our impacts to preserve the existing biodiversity and the services it provides.

My research aims to understand the mechanisms by which fish evolve and adapt to hostile or changing environments. Understanding the genetic and phenotypic evolutionary processes of adaptation to extreme conditions will help us discern the mechanisms of the resilience of life, and its limits. In a broader context, my work aims at revealing the capacity of today’s life to withstand predicted environmental changes and provide the scientific evidence necessary to motivate ecosystem management and conservation policies.

An important part of my work focuses on Antarctic fishes and aims at understanding the genetic regulations and evolutionary forces that shaped adaptation to the frigid Antarctic waters to address the potential of Antarctic life to withstand predicted climate change. Antarctic fishes represent a fantastic model to study evolution and adaptation to extreme conditions. Antarctic notothenioids are the most plentiful group of fish that survived, diversified, and continue to thrive in the constantly near-freezing waters of Antarctica – an environment that is tightly linked with their survival. Among them we can also find the truly unique white-blooded icefishes, the only vertebrates living without hemoglobin. But climate change is unfolding at the poles at a pace faster than anywhere else on Earth and reports of major perturbations in seasonal sea ice, ice shelves, and primary productivity are now daily news. A cascade of responses from molecular to community levels are expected. Despite these alarming warnings, we lack a comprehensive understanding of the resilience and adaptive potential of life in the Southern Ocean and we do not know if the evolutionarily exceptional and highly endemic Antarctic fish fauna will be able to withstand the forecasted changes to their environment. Research at this last frontier is urgent. Antarctic fishes are not only important because of their heritage value, but also because they are at the forefront of a global change, informing us on the future threats and challenges other aquatic environments on the planet may soon be facing.