The initial colonization of Norway occurred by a coastal route that relied on complex maritime transportation and subsistence technologies. Evidence suggests a strong reliance on marine resources throughout the Holocene and testifies to the significant time depth of maritime adaptive strategies in the area. Recent human ecodynamic research, however, questions the timing and evolutionary pathway responsible for bringing about fully maritime adaptive strategies in Arctic Norway. Consequently, this paper highlights the issue of how to conceptualize adaptive shifts within an already established maritime economy. By combining palaeodemographic modelling with archaeological and environmental records, significant synchronous changes are demonstrated across parameters including population size and packing at coastal sites, increasing investment in maritime subsistence strategies and a particular productivity increase in the marine environment. Contrary to established predictions, the increasing reliance on marine resources does not appear to be a response to decreased terrestrial productivity necessitating intensification through reduced diet breath. The adaptive shift in Arctic Norway rather appears to have taken advantage of favorable ecological conditions that facilitated human population growth. This adaptive success was mediated through higher-cost/higher-yield procurement strategies that included mass-harvesting and –processing, proliferated through technological innovations such as deep-sea fishing and ground slate technology. The results therefore challenge the concept of “intensification” as a negative risk-reduction strategy and goes some way in explicating the hallmark demographic and adaptive properties of high-latitude, maritime hunter-gatherers in the ethnographic record.