Individuals borned in captivity may have a lower fitness than wild individuals (Araki et al. 2008; Williamsson et al. 2010). In aquaculture structures, fish have food ad libitum, do not encounter predation risk and are maintained in controlled environmental conditions. Those structures may induce differences with wild counterparts such as a loss in behavioural expression useful in the wild (Berejikian et al. 1996; Benhaim et al., 2012). Young stage survival is a critical moment in population dynamics and survival is linked to capacity to find and to capture preys (Adriaenssens & Johnsson 2011), to swimming and exploratory capacities (Braithwaite & Salvanes 2005) and to capacity to detect danger (Brown & Grant, 2003; Holmes & McCormick 2010). We propose a set of behavioural experiments to measure those capacities in young of year (YOY) European sturgeon, a species in critical danger of extinction. The last population comes from the Gironde (last natural reproduction in 1994), and it is sustained since 2007 by stocking thanks to a captive stock.