Protecting Galápagos' marine ecosystems: Biosecurity and network design against invasive species from tourist vessels.

The modern world is characterized by high connectivity, enhancing economic productivity, and global communication, but outpacing our ability to manage its consequences. This connectivity increases the risk of pathogen, pest, and invasive species transmission. In the Galápagos islands, Ecuador, tourist vessel networks operate with limited restrictions and connect high conservation value locations, boosting tourism and the economy. These vessels frequently travel between multiple islands, leading to moderate connectivity and high vessel promiscuity. To prevent the spread of invasive species via these vessels, we propose a biosecurity system that combines social network tools with risk management frameworks that balances environmental protection with economic values. Our research suggests that leveraging environmental mismatches between island pairs and creating small-world networks can provide a functional and cost-effective biosecurity solution. These findings have global relevance for managing the spread and impact of invasive species worldwide.