I am interested by population dynamics and the numerous factors which are shaping them in a context of global change. As part of my PhD conducted under the supervision of Vincent Devictor and co-supervised by Vasilis Dakos, I try to identify combinations of early warning signals announcing abrupt shifts in population abundance. I apply various methods to search for such signals within empirical time series from worldwide fisheries. The goal is also to be able to link the trajectories followed by different fish populations to the conditions and pressures to which they are (or had been) exposed. Those approaches aim at the implementation of dynamical tools assessing the level of vulnerability of fisheries in order to inform stakeholders about the degree of emergency required in the enforcement of effective measures to prevent rapid and long-lasting collapses of fisheries.