Our purpose in the present work is to make a methodological contribution to enrich the SYAL concept from two points of view. Firstly, as a critical reconsideration of the theory of territorial development, and more specifically SYAL development, taking into account the fact that the local institutional framework is the result of the complex - even conflictive - interaction of economic rationales based on diverse cultural logics. Secondly, as an analysis of the strategies promoted by this type of development, identifying the endogenous components which strengthen and reinforce in local actors the ability to reflectively structure and re-structure system relationships at the territorial level. The empirical-ethnographic support for these reflections is drawn from two zones of Chile's southern coastline. The first, in the southern Aysen Region, illustrates the dilemmas and responses of local-traditional economies based on small-scale fishing in the face of the sustained growth of the captive salmon production mega-industry along a large part of the coastline. The second, in the neighbouring Los Lagos Region, reports on the strategies of traditional small-scale mussel-growers in the Reloncaví Estuary, in the context of the invasion of their economic space by multinational companies and the technification of their traditional systems.