Local ecological knowledge and perception of the causes, impacts and effects of Sargassum massive influxes: a binational approach

Coastal communities of the Caribbean Sea and Gulf of Mexico have been affected by atypical influxes of pelagic macroalgae (Sargassum genus) since 2011, entailing ecological, economic and social impacts in need of characterization. We compiled and documented local ecological knowledge (LEK) and perceptions across diverse stakeholder groups from coastal communities in Mexico (Quintana Roo) (n=50 participants) and the United States (Florida) (n=36 participants) through on-site and online interviews and workshops undertaken from January to March of 2022, to understand how the knowledge of this phenomenon varies among communities and to characterize ecological and well-being impacts. Participants in Quintana Roo associated these influxes with both global phenomena (e.g., climate change) and local scale processes (e.g., currents/wind patterns) while Florida participants associated these events more with the latter. The communities in both regions perceived that the economy and the environment were the most impacted well-being categories. While influxes effects were mostly negative (80%) according to Quintana Roo participants (e.g., affected fisheries), Florida participants considered many positive effects of Sargassum (40%) on several well-being and ecological components (e.g., nursery habitat for marine species). In general, the perception of Sargassum as a problem was less pronounced in Florida, and these differences in perception are related to the magnitude of these influxes' effect on the daily life of these communities. Overall, macroalgae management is still mainly focused on beach cleanup. Documenting LEK is important to delineate scientific research priorities and to provide decision makers with resources to develop efficient public policies and coastal management decisions.

Automated summary

Coastal communities in the Caribbean Sea and Gulf of Mexico have been experiencing unusual influxes of pelagic macroalgae since 2011. A study was conducted to understand the knowledge and perceptions of this phenomenon among communities in Quintana Roo, Mexico and Florida, United States. Participants associated the influxes with both global phenomena and local-scale processes, and perceived impacts on the economy and environment. While the effects were mostly negative according to Quintana Roo participants, Florida participants considered several positive effects on well-being and ecology. The study highlights the importance of documenting local ecological knowledge for research priorities and decision making.