The interdisciplinary study investigated marine citizenship responsibilities and rights using pure mixed methods and an inductive research design. The aim was to investigate a wide rage of influences upon marine citizenship including participant characteristics, attitudes and values; relationships with the ocean as a place; and involvement and views about marine decision-making. Participants were active marine citizens, in order to understand retrospectively what their pathways to marine citizenship entailed. The study included an online survey and face-to-face interviews. Interviewees were survey participants purposefully selected to represent a diversity of the variables, and the interviews were conducted alongside or subsequent to a marine citizenship activity of the interview participant's choosing, to further qualify their personal experience of marine citizenship. The data were used to produce a PhD thesis which expanded the definition of marine citizenship to include a right to participate in marine decision-making, and identified a theoretical concept of marine identity as having a key role in motivating deeper marine citizenship.The negative anthropogenic impacts upon the world ocean are accelerating. Marine citizenship has been proposed as a policy channel to work at an individual level of responsibility to improve marine environmental health and contribute to the achievement of a sustainable future. This interdisciplinary research reflects the principles of post-normal science, through its epistemologically pragmatic and pluralist approach to broadening our understanding of marine citizenship. Drawing on environmental psychology, human geography, environmental law, green political theory, and sociology, this research considers marine citizenship according to four key research questions: i) What is marine citizenship and who participates it? ii) How are institutional policy frameworks of marine citizenship understood, interpreted and experienced by participants? iii) How do motivational and value-based factors influence marine citizenship choices? And iv) How do place-related factors influence the practice of marine citizenship? Mixed methods were used to bring together a range of data and maximise their thesis contribution. The research design consisted of an online survey of active marine citizens reached via three case studies: two community marine groups and one national citizen science project. This was followed by ethnographic observation of marine citizenship in practice and open-ended interview of purposively selected participants, to maximise insight into diversity of marine citizens and gain in-depth qualitative data. The results provide a number of novel insights into the conception and motivation of marine citizenship. In my research, prevailing interpretations of marine citizenship as a set of pro-environmental behaviours are extended by situating the concept within citizenship theory. Here I give additional focus to the understanding of citizenship as the right to construct and transform society, and how public participation in marine decision-making is perceived as being under-served by legislation and procedure. My data show that marine citizenship is influenced by a complex of interacting variables and that there is no one kind of person who becomes a marine citizen. Yet environmental identity, stimulation 5 and conformity basic human values, climate change concern, place attachment and, in particular, place dependency are important factors for ‘thicker’ marine citizenship. The research uncovered a human affinity with the ocean through unique marine place attachment, or thalassophilia. These findings challenge normative approaches to pro-environmental behaviour, which frequently focus on environmental education, information, and awareness raising. Creating opportunities for marine experiences promotes attachment to the ocean and in turn ‘thicker’ marine citizenship. The results collectively point to a marine identity, formed through ocean connectedness and enabled by favourable socio-economic and policy conditions. When associated with good ocean health, marine identity can underpin and be reinforced by marine citizenship. Marine citizenship coincides with broader environmental and civic citizenship; therefore marine experience opportunities may contribute to wider acceptance of policy and public participation in the paradigmatic change now facing humans, as we attempt to mitigate and adapt to climate change in the coming years.

Data was collected between 2017 and 2018. Participants were active marine citizens in the UK who were identified via three case studies (two local/regional marine groups and a national marine citizen science project). The study included an online survey with both quantitatative and qualitative responses from 280 participants drawn from the three case studies via self-selection. The survey quantitative data includes basic demographics, geographical location, basic human values scores (using Schwartz Portrait Values Questionnaire items), and likert scale responses to items relating to environmental identity, place attachment, place identity and place dependency. The survey qualitative data collected relates to marine and general citizenship activities participated in, participant views on the nature and utility of marine citizenship, and participant experiences of marine decision-making processes. Ten interviews were conducted with survey participants who were selected purposefully to represent a diversity of the variables included in the survey. The interviews were conducted alongside or subsequent to a marine citizenship activity of the interview participant's choosing, to further qualify their personal experience of marine citizenship.