Serranilla is a protected island of the Seaflower Biosphere Reserve, far from dense human population. These characteristics could help sustain structurally complex coral reefs, often associated with higher biodiversity, abundance, and biomass of reef-associated organisms, including reef fish. However, the multiple threats present in Serranilla, including intense illegal fishing, can impact coral ecosystems generally and also specific key groups, such as the parrotfish, in particular. During the “Seaflower Research Expedition 2017”, we assessed how structural habitat complexity influences reef fish assemblages. In addition, we explored differences in parrotfish species (family: Scaridae) between Serranilla and San Andrés, the most populated island in the Archipelago. On Serranilla, we found that habitat structure, rugosity, and coral cover accounted for up to 66% of variation in reef fish diversity, abundance, and biomass, with values being higher on more complex reefs. Parrotfish species differed between the islands, with larger species supporting higher biomasses at Serranilla, by comparison with San Andrés; however, the abundance, biomass, and lengths of parrotfish species were low in both areas compared with those reported from other protected Caribbean reefs. Our study indicates that despite the evident relationship between structurally complex habitats and reef fish, other threats in Serranilla could be affecting parrotfish populations, such as illegal fishing, a widespread activity in the area.

Insular and coastal territories like those in the Seaflower Biosphere Reserve are exposed to strong winds, waves, storms, and hurricanes. In November 2020, Hurricanes Eta and Iota provided a costly reminder of the risks facing Seaflower’s people and ecosystems. Coral reefs and mangroves are natural shields, reducing wind and wave strength during normal and extreme conditions. These coastal protection ecosystem services (ES) are vital for human safety and well-being, and become more important given the heightened vulnerability of low-lying insular islands to climate change impacts. These ecosystems also provide biodiversity refuge ES for fishes and shellfish, key for food security and resilience to global challenges like hurricanes, sea level rise, and global warming. Despite their importance, these valuable ecosystems are threatened by anthropogenic pressures, jeopardizing the survival and well-being of islanders; their restoration and recovery require improved management and decision-making, and heightened societal awareness of our dependence on marine ecosystems and their potential as climate change adaptation solutions. We identify ES provided by coral reefs and mangroves, interdisciplinary management tools, and recommendations to motivate society and decision-makers to expand efforts for the protection, restoration, and use of these ecosystems as Nature-based Solutions for climate change adaptation and mitigation in Seaflower.

Climate Change (CC) is a global phenomenon with differentiated impacts. Its effects are felt in marine and terrestrial ecosystems and organisms, and in the most vulnerable economies and societies. CC is altering the ocean’s chemistry, initiating cascading socioenvironmental impacts. The fisheries sector is the most affected. In the Western Caribbean’s Archipelago of San Andrés, Providencia, and Santa Catalina, identified as having the highest climatic risk, these impacts are pronounced. This study comprehensively reviews existing knowledge on climate change effects on fishery resources and incorporates fishers’ perceptions through two rounds of surveys in 2019 and 2022. The findings reveal significant consequences for fishery resources, including alterations in biological properties and species distribution, loss of critical coastal fish breeding habitats, reduced fisheries productivity, and increased local and cross-border conflicts over fish resources. Especially, after the destructive impact of Hurricane Iota (2020), fishers shifted their hazard perception, elevating hurricanes as a significant threat alongside drought. These evolving perceptions emphasize the need for comprehensive policy strategies to address multiple hazards and their interactions, aligning with fishers’ priorities and enhancing the resilience of the fishing sector. This research underscores the urgency of ecosystem-based and co-management policies, alternatives for artisanal fishers, and heightened climate risk perception.

Microalgae constitute the basis of marine food webs. However, the massive growth of some species and the toxicity of others may represent a serious threat to human health, fisheries, mariculture, and tourism. Evidence shows that global warming, climate change, nutrients, and sewage discharge favor microalgal blooms, which are becoming more frequent, intense, and lasting. In the Caribbean Sea, ciguatera poisoning, one of the syndromes caused by toxic dinoflagellates, has increased its incidence in the past three decades. Despite the potential risks, there is no management plan for this and other harmful algal blooms (HABs) in San Andres island, Colombia. We analyze the presence of toxic dinoflagellates along with the incidence of ciguatera in the Seaflower Biosphere Reserve (SBR). Considering that effective climate change adaptation and mitigation decisions are based on relationships between science and society, involving a wide variety of analytical methods to evaluate associated risks and benefits, we propose to evaluate the potential effects of HABs, focusing on the economic value of their impacts on fishing and tourism. We propose an early warning system conceptual model, based on a monitoring program, as a strategy to contribute to the governance and the management effectiveness of the different institutions of the SBR.