Conference Proceeding

Behavioral experiments on post-larval fishes in the north-eastern Corsican coast (Mediterranean Sea)

Ms. Amélie ROSSI,

Demersal fish represent a very important part of coastal marine biodiversity. Their life cycle is generally defined in two major phases: a pelagic larval phase and a benthic adult phase. Once the adult stage is reached, individuals are generally sedentary and strongly dependent on the benthic compartment (food search, habitat ...). Thus, the pelagic larval phase plays a decisive role: it allows the dispersal of individuals and the colonization of new coastal habitats. It therefore plays a crucial role in the recruitment and dynamics of coastal populations. So, the pelagic larval phase is a true issue for research and studies in marine bio-ecology, not only in terms of fundamental knowledge but also for the management of fish resources. This work is directed on the behavioral study of post-larvae (the last stage of the pelagic larval phase) of species founded on the north-eastern Corsican coast (Mediterranean, France). The objective is to conduct both in situ and laboratory experiments, from individuals sampled in the field (using light traps). Experiments carried out in the field make it possible to analyze the orientation behavior of post-larvae in their natural environment using an observational system, the DISC (Drifting In Situ Chamber, Paris et al., 2013). This device is made to evaluate the orientation of individuals directly in the pelagic environment without human disturbance or reference frame, while apprehending various environmental parameters perceived by individuals (depth, current, temperature, etc.). Laboratory experiments are conducted to estimate the swimming capacities of post-larvae using a swimming chamber (Loligo® Systems). Thus, the critical swimming speed can be defined (called Ucrit), which is a measure to estimate a “routine swimming speed” in the natural environment. These two kinds of experiments provide fundamental knowledge for the Mediterranean marine environment. Indeed, they improve the existing database on the subject (new species and new coastal environment studied) and may be used to assist the management and protection of coastal environments along the Corsican coast, including by implementing data in computer models of larval dispersion by the currents.

Published: 18 July 2017