Summary of Abstract Submission

Abstract Submission No. IO50-09-0003PresentationOral

ECOSYSTEM RESEARCH IN THE INDIAN OCEAN IN A FISHERIES PERSPECTIVE: BETTER INTEGRATION FOR BETTER MANAGEMENT

Francis Marsac*1

1 Institut de Recherche pour le Developpement (IRD), France

ABSTRACT :

Developing research that could inform and guide the riparian countries of the Indian Ocean towards a better use of marine resources to secure food supply was one of the objectives of the IIOE. Ecosystem research, quite complex to implement, took off gradually in the years following the IIOE. The considerable corpus of knowledge obtained from observing systems (ships, moorings, drifters and satellite) during the past 25 years and a better understanding of the climate variability at various scales, have permitted the implementation of integrated approaches in fisheries management, where physical and biological environment, fish behavior, fleet development and harvesting strategies interact closely. We present the case of the Indian Ocean tuna fisheries, which started to expand at the time IIOE was launched. Tuna fisheries are now well developed. Using empirical and modeling approaches, we show that physical and biological processes occurring at both basin- (notably ENSO and Dipole events) and meso-scales are major drivers of yield and fishing effort spatial distribution of tuna fisheries. Our results account for individual tuna behavior (as revealed by tagging), ontogenic cycle (spawning versus trophic migrations), diet composition, food web structure and interactions in the pelagic ecosystems along with climate forcing and environmental conditions. Eventually, we underline the main challenges to take up in order to improve ecosystem-based fisheries management in the Indian Ocean.