In a small-scale coastal fishing system, the carrying capacity issue may appear in several forms, disguised as an economic slump, an increase in competition or an escalation of disputes arising at sea or on land which are carried over into fishing. The first task of carrying capacity analysis is to distinguish actual population-induced welfare reduction from ordinary economizing behavior under conditions of temporary resource scarcity. Both situations make it necessary to alter the strategy of production. A way to evaluate the carrying capacity of a fixed-territorial fishery indirectly by focusing on fishermen''s perceptual change of resource and territorial availability is outlined. Information on this topic is readily accessible through analysis of the daily decision-making procedure used to select fishing spots. The 2nd goal of studying carrying capacity is to examine fishermen''s own conceptions of the sources of fishing pressure, its tolerable limits and its consequences. Carrying capacity represents an ideal threshold, but the fishermen in Brazil definitely seemed to operate and organize production in terms of what might be called an ethnoecological model of resource use. Even under their own traditional methods, they regarded both overfishing and cutthroat competition as a situation which may well develop given the proper incentives. The incentive most to be avoided is any outside factor which will disrupt the flow of authority over fishing territories and their customary means of recruitment of manpower to fishing. Controls on the opportunity structure of fishing are consciously and deliberately exercised by traditional captains who own chunks of lunar-tide fishing space. The biological concept of carrying capacity may be retained to help visualize the limits to fishery expansion. In the case of canoe fishing in Bahia, traditional fishermen themselves did much toward stabilizing their production system. The critical point here is the time depth of their adaptation. Through an extended period of trial and error, it was possible for fishermen to interpret expansion limits and set the intensity of fishing accordingly. In planning their economic strategies as if there were always a potential overfishing situation, they had established temporary territorial claims which insured that only a gradual expansion of fishing operations took place. Thus, the opportunity structure of traditional fishing, and by extension the population as a whole, was able to grow at a resource harvest rate which was compatible with continuing resource availability within a fixed location. Trouble only came to canoe fishing when the previously adaptive ratio of production units to available water space was disrupted by the unregulated entry of a competitive group of nylon fishing entrepreneurs.