Community structure and trophic interactions in a coastal management and exploitation area for benthic resources in central Chile

Abstract

Management and Exploitation Areas for Benthic Resources (MEABR) is the most common type of coastal marine protected area in Chile, being used for managing inshore benthic resources since 1991. The structure of the biological community in MEARBs are poorly studied and it is though that a better understanding of this framework is key to sustainability. Here we present a food web model to characterize the benthic community and key functional groups in the MEABR of San Vicente Bay (36°44′S–73°09′W), using the Ecopath with Ecosim software (EwE). The Chilean albalone Concholepas concholepas is the main fishing resource in many MEABRs, including the MEABR of San Vicente Bay. The structuring role of main predators is assessed and compared using mixed trophic impacts (MTI) analysis and through calculate an interaction strength (IS) index.The results show that the main flows of consumption in the benthic community of the MEABR of San Vicente Bay occur in lower trophic levels (TL ≤ 2), while flows in higher trophic levels (TL ≤ 3) are related mainly to C. concholepas. The MTI and IS analysis show that C. concholepas and crabs are the groups whose changes in biomass caused the greatest change in total system biomass in MEABR of San Vicente Bay and can be characterized as playing important ecological roles in that places. Exploitation resulted in direct and indirect trophic impacts that have the potential of affecting the sustainability of this and other MEABRs. Future research should also aim at advancing knowledge on basic ecological parameters of exploited benthic communities beyond target species.