An appraisal of systematic conservation planning for Pacific Ocean Tropical Islands coastal environments

The MANA (MANagement of Atolls, 2017-2022) project for pearl oyster aquaculture management in the Central Pacific Ocean using modelling approaches: Overview of first results

This editorial presents results of the MANA (MANagement of Atolls) project compiled in the form of a Marine Pollution Bulletin collection of 14 articles. MANA is a project funded by the French Agence National pour la Recherche that specifically addresses the development of knowledge and management tools for pearl farming atolls, with a focus on the spat collecting activity in French Polynesia. The 14 papers cover the range of thematic tasks described in the initial project, including atoll geomorphology and bathymetry, climate forcing, atoll lagoon and rim hydrodynamics, typology of atolls, evaluation of remote sensing data for monitoring atoll lagoons, and development of numerical models and spatially-explicit tools that altogether have contributed to the applied objectives. In addition, this editorial draws an update on the pearl farming industry in French Polynesia with the latest statistics, and discusses the next targeted priorities for research programs focusing on pearl farming atolls.

Spatial Solutions and Their Impacts When Reshuffling Coastal Management Priorities in Small Islands with Limited Diversification Opportunities

In small islands, the potential for new coastal activities and management options are often spatially limited. To reduce dependence on external factors and increase the resilience of populations to global changes and fluctuations in international markets, a recommended pathway is to diversify activities. We used a systematic prioritization tool with single and multiobjective zoning to explore the feasibility of scenarios at various levels of spatial diversification in the Gambier lagoon (French Polynesia), where black pearl culture is economically and spatially dominant. Local managers are committed to economic, livelihood, and environmental sustainability and agree that prioritizing both artisanal fisheries, which provide local food security, and ecosystem conservation should also be considered. Diversification options included the optimized reallocation of farming concessions and the identification of different types of conservation areas while taking into account traditional management areas. The scenarios were set to minimize surface areas and loss of access to existing fishing grounds. The solutions were compared between the scenarios with different cost metrics, allowing further discussions with stakeholders and managers. The Gambier case study shows that exploring diversification options in small islands using systematic prioritization tools can provide local managers with tailor-made plans adapted to island development questions.

A systematic prioritization approach for identifying suitable pearl oyster restocking zones following a mass mortality event in Takaroa Atoll, French Polynesia

Oyster farming for black pearl production is central in French Polynesia. It is the second source of national income and provides substantial job opportunities, notably in remote atolls. However, this sector has been undermined by successive crises, such as mass-mortalities of wild and farmed oyster stocks that have impacted entire lagoons. An option to revive the activity consists of reintroducing oysters in strategic benthic locations selected to maximize reproduction and dispersal of larvae throughout the lagoon, hence promoting recolonization and spat collection for farming. For Takaroa, a Tuamotu atoll recently impacted by mortalities, a systematic prioritization approach identified these restocking sites, using environmental and socio-economic criteria such as: location of suitable habitats for oyster settlement, larval connectivity estimated from hydrodynamic circulation model, farming waste accumulation, and opportunity cost to fishers and farmers who lose access to restocking areas. This approach provides managers with a portfolio of restocking options.

The tropical Pacific Oceanscape: Current issues, solutions and future possibilities

Marine ecosystems across the world's largest ocean - the Pacific Ocean - are being increasingly affected by stressors such as pollution, overfishing, ocean acidification, coastal development and warming events coupled with rising sea levels and increasing frequency of extreme weather. These anthropogenic-driven stressors, which operate cumulatively at varying spatial and temporal scales, are leading to ongoing and pervasive degradation of many marine ecosystems in the Pacific Island region. The effects of global warming and ocean acidification threaten much of the region and impact on the socio-cultural, environmental, economic and human health components of many Pacific Island nations. Simultaneously, resilience to climate change is being reduced as systems are overburdened by other stressors, such as marine and land-based pollution and unsustainable fishing. Consequently, it is important to understand the vulnerability of this region to future environmental scenarios and determine to what extent management actions can help protect, and rebuild ecosystem resilience and maintain ecosystem service provision. This Special Issue of papers explores many of these pressures through case studies across the Pacific Island region, and the impacts of individual and cumulative pressures on the condition, resilience and survival of ecosystems and the communities that depend on them. The papers represent original work from across the tropical Pacific oceanscape, an area that includes 22 Pacific Island countries and territories plus Hawaii and the Philippines. The 39 papers within provide insights on anthropogenic pressures and habitat responses at local, national, and regional scales. The themes range from coastal water quality and human health, assessment of status and trends for marine habitats (e.g. seagrass and coral reefs), and the interaction of local pressures (pollution, overfishing) with increasing temperatures and climate variability. Studies within the Special Issue highlight how local actions, monitoring, tourism values, management, policy and incentives can encourage adaptation to anthropogenic impacts. Conclusions identify possible solutions to support sustainable and harmonious environment and social systems in the unique Pacific Island oceanscape.