World-wide, the oceans are experiencing unprecedented rates of change associated with human activities. Overexploitation of species, degradation of habitats, biodiversity loss, a growing human population and changes in sea and land use are fundamentally altering the structure and function of marine ecosystems (Scheffer et al., 2001; Lubchenco et al., 2003; Jennings and Brander, 2010; Este et al., 2011; Díaz et al., 2019; Halpern et al., 2019). Effective and sustainable marine conservation and management strategies are urgently needed to halt the continued degradation of the world's oceanic and coastal environments (Devillers et al., 2015; Lubchenco and Grorud-Colvert, 2015; Ban et al., 2017; Roberts et al., 2017; Alvarez-Fenandez et al., 2020; Laffoley et al., 2020). International conventions and policies, most notably the Convention of Biological Diversity and the United Nations Sustainable Development Goal 14, called for at least 10% of the world's oceans to be protected by 2020 [Convention on Biological Diversity - Aichi biodiversity targets, 2010; United Nations Educational Scientific Cultural Organisation (UNESCO), 2017]. At present, an estimated 7.7% of the world's oceans are designated as Marine Protected Areas (MPAs) (The United Nations World Database of Protected Areas, 2021), with discussions to determine the type and extent of marine protection required post- 2020 currently underway (Campbell and Gray, 2019; Gownaris et al., 2019).

Across the globe there are aspirations of reversing biodiversity loss through the protection of 30% of the world oceans by 2030 and a vision of living in harmony with nature by 2050. (The United Kingdom Government, 2018; Convention of Biological Diversity, 2019; The International Union for Conservation Nature, 2021) The declaration of the United Nations Decade of the Ocean Science for Sustainable Development encompassing 2021-2030 [United Nations Educational Scientific Cultural Organisation (UNESCO), 2017] has been developed to provide a common framework to unify and enable countries to undertake the ocean science necessary to sustainably manage oceans on a global scale and to ensure that connections between science, policy and societal needs are at the heart of the process (The United Nations decade of ocean science for sustainable development, 2020). One of the proposed mechanisms for achieving such ocean management is the designation of large-scale highly protected MPAs (Dudley et al., 2010; Leverington et al., 2010; Edgar et al., 2014; Watson et al., 2014). Highly protected MPAs can be a powerful conservation tool if appropriately managed from the point of designation (Lubchenco and Grorud-Colvert, 2015; Gownaris et al., 2019; Schratzberger et al., 2019; Alvarez-Fenandez et al., 2020). To effectively designate and sustainably manage such large areas of ocean and sea that can encompass a myriad of habitats and species, it is crucial that we understand the structure, function and resilience of the ecosystems therein. Such decisions involve many sources of evidence and require consideration of a complex interplay of social, political, legal, cultural, economic, and environmental concerns (Schratzberger et al., 2019). The wide range of competing interests means that, to be effective, decision-makers need to be presented with this evidence in a timely and accessible manner so it can be used to inform the development of future management and policy strategies.

In 2016, the UK Government established its Blue Belt Programme¹, a broad initiative to develop and enhance marine management, protection and conservation across a number of its Overseas Territories. The Blue Belt Programme has focused on seven territories, including British Antarctic Territory, British Indian Ocean Territory, Pitcairn Islands, St Helena, Ascension Island and Tristan da Cunha, and South Georgia and the South Sandwich Islands.

This Programme has contributed to the delivery of the UK Government's commitment to provide protection of over four million km² of marine environment across the UK Overseas Territories (UKOTs). This has been achieved through the provision of ongoing support for existing strategies of marine protection within British Indian Ocean Territory, South Georgia and the South Sandwich Islands and within British Antarctic Territory and through assisting in the development of new marine management and protection strategies within Pitcairn, St Helena, Ascension Island and Tristan da Cunha Exclusive Economic Zones (EEZs).

High-level objectives of the Blue Belt Programme have been to:

The Blue Belt programme is delivered by the UKOTs in partnership with the Center for Environment, Fisheries and Aquaculture Science (Cefas) and the Marine Management Organization (MMO), in addition to collaborators and experts from around the world to generate additional knowledge to ensure that existing and newly developed marine protection strategies are well-designed, and that valuable marine areas and zones are effectively managed and monitored.

The geographic scope of this Frontiers in Marine Science Research Topic demonstrates the amount of work currently being undertaken in partnership with many UKOTs as they seek to protect and sustainably manage their marine estates. Included are studies encompassing UKOTs within the Blue Belt Programme (South Georgia and the South Sandwich Islands, Tristan da Cunha, St Helena, Ascension Island, Pitcairn Island and the British Indian Ocean Territory), as well as Monserrat. It brings together 22 papers that focus broadly on four key themes that demonstrate the importance of scientific data collection and how it has been utilized to deliver policy relevant evidence and advice for UKOT decision makers.

The articles contained in this issue represent the outcomes of policy-driven, applied research, developed to fill the most critical knowledge and evidence gaps in the marine decision-making process. The outcomes of this work have already had demonstrable impact upon major policy decisions within the UKOTs, including the designation of large MPAs, the safeguarding of fisheries resources, the protection of vulnerable ecosystems, and the sustainable use of the marine environment. The articles highlight many of the challenges that have been overcome while working in remote locations with varying levels of infrastructure and governance. They demonstrate the importance of communication and what can be achieved through partnership working between Government agencies, non-governmental organizations, academic partners, and local stakeholders.

We, the authors, are proud to have worked alongside our UKOT colleagues to deliver co-created science that has been crucial to evidence-based decisions made during our journey toward sustainable ocean governance. Many of the UKOTs are remote communities that depend heavily on their marine environments and have limited means for economic diversification. Their willingness to consider their economic goals alongside those of global marine protection cannot be underestimated and they should be wholeheartedly congratulated on their commitment to building a sustainable future for our oceans.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

DF was employed by the company MRAG Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.