Institut Méditerranéen d’Océanologie
Accueil du site > Agenda > Nos séminaires > Rappel / Séminaire MIO : Antonio Di Franco, post- doctorant de l’Université (...)

Rappel / Séminaire MIO : Antonio Di Franco, post- doctorant de l’Université de Nice-Sophia Antipolis - Using multiple approaches to investigate patterns of dispersal and connectivity in two coastal fish : implications for marine protected areas design

Version imprimable de cet article

Le vendredi 19 janvier à 11h en salle Egée

Intervenant :

Antonio Di Franco is a post-doc researcher at the University of Nice-Sophia Antipolis (France). He was involved in national and international projects on Marine Protected Areas (MPAs) with particular emphasis on fish dispersal at multiple life stages (and its implication for the design of network of MPAs), reserve effect assessment and the key-features determining successful management of fisheries in a socio-ecological context. He has authored 34 ISI papers published in international journals.

Abstract :

Estimates of dispersal and connectivity patterns are vital to properly manage fish stocks and design marine protected areas (MPAs) and effective networks of MPAs. However, assessing dispersal and connectivity patterns is an intricate task because of the difficulty to track individuals throughout entire life cycle. Multiple approaches are available to assess dispersal and connectivity of fishes, among which biophysical models, population genetics, tagging and assessment of the spatio-temporal distribution of larvae and juveniles (i.e. settlers). However, each of these different approaches measure different things, often over different timescales, and has some drawbacks. Therefore, combining multiple approaches can be the best option to assess dispersal and connectivity patterns as each method compensates the limits and constraints of the others.

Here we investigated dispersal patterns at larval and post-settlement stages (i.e. between settlement and recruitment to the adult fraction of the population) in two congeneric fish : the white seabream Diplodus sargus and the two banded seabream Diplodus vulgaris. The study was carried out in SW Adriatic Sea (Italy, Mediterranean Sea) along about 180 km of coastline, enclosing both a marine protected area (Torre Guaceto MPA) and fished areas.

Using underwater visual census, reproductive output assessment, analyses of otolith microstructure and microchemistry, Lagrangian modeling and genetics, we highlight that Torre Guaceto MPA is an effective source of propagules (i.e. eggs and larvae) that can disperse at 100s of km, and that post-settlement dispersal (occurring from 0 to >100 km) may then re-arrange distribution patterns. This finally results in highly connected local populations lacking genetic structure.

Under hydrographic conditions (i.e. sea-currents) similar to the ones characterizing the study area, a network of MPAs sized as TGMPA (i.e. about 8 km) and placed at distance of 100-200 kilometers could be effective for both conservation and fishery goals of the two investigated species in the south-western Adriatic area.