Evaluating the effectiveness of Marine Conservation Strategies: challenges for sustainable ocean management

In recent decades, the conservation of marine ecosystems has garnered global attention due to the substantial evidence of ocean degradation and biodiversity loss. Despite significant advances in marine science, a comprehensive understanding and adequate protection of marine environments still need to be improved. Marine ecosystems face cumulative anthropogenic pressures, both locally and globally, including overfishing, pollution, and climate change, which diminish biodiversity and degrade ecosystem services essential for food security, carbon storage, and climate regulation. As a response, Marine Protected Areas (MPAs) have emerged as a primary conservation tool under frameworks such as the Convention on Biological Diversity (CBD) and the recent High Seas Treaty. However, the effectiveness of Marine Conservation Strategies (MCSs) is debated due to several factors. These include remote locations, unclear zoning, and poor delimitation (14%), lack of regulations or contradictory regulations (8%), lack of stakeholder involvement (7%), global warming or warming waters (7%), and weak governance or coordination (6%). These issues are the main drivers of inefficacy, often leading to these strategies being labeled as "paper parks" which are protected areas in name only.

This study provides a systematic literature review (n=225, among 1772 articles) of the effectiveness of Marine Conservation Strategies (MCSs) in addressing the challenges posed by these drivers of ecosystem and biodiversity loss, considering that we currently have different spatial management tools to conserve marine ecosystems. We examine the diverse conservation strategies, comparing their strengths, limitations, and interactions within marine spatial planning frameworks. By synthesizing existing literature and identifying research gaps, this review aims to support the development of adaptive and dynamic conservation tools that align with the Kunming-Montreal Global Biodiversity Framework and the Biodiversity Beyond National Jurisdiction (BBNJ) agreement. Our findings underscore the necessity for multifaceted, resilient conservation strategies, considering the temporal and spatial scales with repercussions in the functional scale, that can adapt to the evolving natural dynamism of marine ecosystems, ensuring long-term sustainability and resilience.