While the ocean space has long been ignored by social sciences, the past 15 years have witnessed an increased interest in the marine environment by scholars in Human Geography. The academic literature on the blue economy, almost non‐existent a few years ago, is now burgeoning. The academic debate has offered some critical assessment of blue economy initiatives, but more needs to be done to address the true place of environmental protection within a blue economy, and to put people at the centre of concerns and analyses. Of particular concern, is the ambiguity of the blue economy concept and the confusion over its social and environmental sustainability, which can ultimately result in harmful practices. An important question is then how should social scientists in general and geographers, specifically, engage with these debates, and in particular how should the potential human and social costs of the blue economy be investigated and addressed while assuring justice and fairness? The papers presented here share the vision that environmental sustainability, justice and equality should be at the heart of the blue economy; not just conceptually, but practically too. The papers pursue efforts to identify blue economy risks and the mechanisms through which they occur; assess the place of inclusion and participation in a sustainable blue economy; define what blue economy policies should include to drive just and sustainable practices; and identify where the dominant understandings of the blue economy and its priorities are coming from. In other words, they put considerations of justice and broader cultural structures at the centre of their concerns and analysis. They also highlight the need to bypass geographical boundaries and gain insights from other disciplines and methodologies to grasp such an encompassing concept, and foster not just a blue economy with social justice, but a blue economy for social justice.

The purpose of this paper is to identify of the gentrification frontier. The gentrification frontier represents a divide between gentrified and ungentrified areas of the city. Based on a case study of Portland, Maine, field research is combined with an analysis of census-derived variables to delineate the gentrification frontier in three time periods 1980-1990, 1990-2000, and 1980-2000. This paper suggests that the existence of an amenity, a revitalized urban waterfront can act as a catalyst for gentrification of the adjacent urban space, thereby creating a gentrification frontier associated with reinvestment in the waterfront. The results of the analysis show that because of low levels of gentrification before 1990 it is only possible to identify the gentrification frontier in the period from 1990-2000. As expected, the gentrification frontier is fragmented and discontinuous. It is located adjacent to an almost continuous area of gentrification that extends along Portland's waterfront.

To enact a just and sustainable blue economy, one must consider all the actors involved in its shaping. This paper argues that a quintuple helix approach to stakeholder engagement – involving government, academia, the business community, and civil society – and an inclusive transdisciplinary action research (TAR) methodology are promising avenues with which to do so. Embracing critical pragmatism as a foundational framework, key ideas from three strands of research are consolidated: (1) the recent work on the geographical dimension of socio‐technical sustainability transitions; (2) the literature on just sustainabilities and just transition; and (3) action research and transdisciplinary approaches to problem solving. This allows for the reimagination of a common future for the blue economy that is developed through a different kind of democratic process driven and informed by co‐learning, and shared experiences. By adopting a transdisciplinary action research approach, actors from different disciplines and spheres of experience can gain a better mutual understanding and find commonality through the open door of collaboration. The theoretical argument presented in this paper is illustrated by a vignette of an ongoing TAR project at Southern Connecticut State University, which outlines the challenges and opportunities inherent to implementing a TAR approach.